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An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae
expand article infoBlaine A. Mathison, Sarah G. H. Sapp§
‡ Institute for Clinical and Experimental Pathology, Salt Lake City, United States of America
§ Centers for Disease Control and Prevention, Atlanta, United States of America
Open Access

Abstract

The classification of “parasites” in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.

Keywords

Acanthocephalans, arthropods, cestodes, leeches, nematodes, parasitology, protozoa, trematodes

Introduction

The online Oxford English dictionary defines a parasite as: ‘an organism that lives in or on an organism of another species (its host) and benefits by deriving nutrients at the other’s expense’ (LEXICO 2020). From a strictly biological perspective, this definition can cover a wide variety of organisms, including, but not limited to, bacteria, viruses, fungi, helminths (worms), protozoans, cnidarians, tardigrades, rotifers, mollusks, and arthropods. However, in the historical concept of the medical community, the term ‘parasite’ refers to animals and other eukaryotic organisms with animal-like affinities, and is usually limited to the protozoans, helminths, and arthropods.

Historically, human parasites have been classified within the broad Linnaean kingdom of ‘Animals’ and divided into taxa with formal categorical names (phylum, class, order, family, etc.). While traditional Linnaean taxa are still commonly used for helminths and arthropods, it is becoming more common to use clade-based systems devoid of formal designations, especially with the taxa collectively called protozoans. Much of this work comes from a better understanding of the evolutionary relationships of organisms based on both morphological and molecular analyses (Adl and Mathison 2019).

Currently, eukaryotes are classified into two domains, Amorphea and Diaphoretickes, as well as additional large clades that do not fit into either of those domains. Within domains are large clades commonly referred to as supergroups. Eukaryotic parasitic organisms fall into five supergroups within these domains: SAR, Archaeplastida, Excavates, Amoebozoa, and Opisthokonta (Adl et al. 2019; Adl and Mathison 2019). For the purpose of this work, the focus is on the traditional human parasitic protozoans (Amoebozoa, SAR, Excavates) and helminths, annelids, and arthropods (all in Opisthokonta). Two groups of organisms that were historically considered protozoans, but are now considered fungi and are not included here, are Pneumocystis jirovecii Frenkel, 1999 (syn. P. carinii f. sp. hominis) and the microsporidia. The genus Prototheca is another opportunistically parasitic eukaryote, but is currently aligned with the algae in the clade Archaeplastida and is also not covered here (Lass-Flörl and Mayr 2007). For detailed descriptions on the higher classifications of eukaryotes, the readers are referred to the work by Adl and colleagues (Adl et al. 2019).

The Amoebozoa include many of the human parasites historically referred to as amebae, including the intestinal amebae Entamoeba, Endolimax, and Iodamoeba, and several of the ‘free-living’ amebae such as Balamuthia and Acanthamoeba (Adl and Mathison 2019). These organisms feed by phagocytosis and move by pseudopods. They lack cilia and most have an environmentally hardy stage (cyst) for dispersal and infection of a new host (Adl et al. 2019; Adl and Mathison 2019). The free-living amebae are not adapted for true parasitism and are only opportunistic parasites when conditions allow for colonization of the human host. Clinically, Acanthamoeba species are usually characterized by their genotypes rather than traditional Linnaean binominal nomenclature (Booton et al. 2005).

The SAR (which commonly refers to Stramenopiles-Alveolates-Rhizaria) includes parasitic coccidians (e.g., Toxoplasma, Cyclospora, Cystoisospora), gregarines (Cryptosporidium), piroplasmids (Babesia), haemosporidians (Plasmodium), ciliophores (Balantioides, formerly Balantidium), and the stremenopile Blastocystis (Adl and Mathison 2019).

Within the SAR, the coccidians, gregarines, piroplasmids, and hemosporidians are obligate parasites and part of the clade Apicomplexa that are characterized by a structure called an apical complex that is used for penetration of the host cell. Motility is usually by gliding or body flexion and feeding is by pinocystosis (ingestion by budding of small vesicles from the cell membrane). Apicomplexans may have one or two hosts and reproduce by sexual reproduction, the end result of which is an oocyst that when mature contains sporozoites that are the infectious stage for a new host (Adl et al. 2019; Adl and Mathison 2019). The Haemospororida (e.g., Plasmodium) and Piroplasmorida (e.g., Babesia) are vectored by sanguinivorous arthropods. Humans are intermediate hosts for Plasmodium, which are vectored by mosquitoes that serve as the definitive hosts. Babesia are zoonotic in humans and in nature typically cycle between a tick vector (definitive host) and a mammalian intermediate host (Adl and Mathison 2019).

The only human parasitic ‘ciliate’ is Balantioides (formerly Balantidium, syn. Neobalantidium). Movement is by numerous cilia and feeding is by phagocytosis. It forms an environmentally-hardy cyst that is the infectious stage for a new host (Adl et al. 2019; Adl and Mathison 2019).

Blastocystis is an enigmatic organism that has historically been variably classified among coccidians, fungi, and algae. The life cycle is still not completely understood, but it has been proposed that it reproduces by binary fission of vacuolar forms within the host and infects a new host via environmentally hardy cysts. Both vacuolar forms and cysts can be detected in stool specimens, and the variability in morphology of the former has created numerous descriptive terms. It has also been suggested it has a third form, an amoeboid form, that is responsible for pathogenesis in the host, but this hypothesis is not yet broadly accepted (Tan 2008). As the molecular epidemiology is becoming better understood, it is becoming less common to recognize Blastocystis by traditional Linnaean binominal nomenclature and more common to base identification on their genetic subtypes (Stensvold et al. 2007; Tan 2008).

The Excavates includes the traditional ‘flagellates’, such as Giardia, Trypanosoma, Dientamoeba, Chilomastix, Leishmania, and Trichomonas, as well as amoeboflagellates, such as Naegleria (Adl and Mathison 2019). All excavates move by cilia (historically referred to as flagella, which are not analogous to the bacterial flagellum) at some point in their life cycles. Most feed by pinocytosis (although the ameboid form of Naegleria and its relatives feed by phagocytosis). The life cycle patterns vary greatly among the excavates. Intestinal flagellates typically multiply by binary fission in the lumen of the intestine of their hosts and have an environmentally hardy cyst stage that is infectious for a new host. The trichomonads lack a cyst stage, and Dientamoeba is unusual in that it lacks external cilia and moves by pseudopods and feeds by phagocytosis, much like the Amoebozoa. The ‘hematoflagellates’ (Leishmania, Trypanosoma, Crithidia, Endotrypanum) have two host life cycles and are transmitted to the human host via an arthropod vector. Amoeboflagellates, such as Naegleria, Paravahlkampfia, Tetramitus, Vahlkampfia, Allovahlkampfia are not true parasites and only infect the human host when opportunities allow for infection and colonization (Adl et al. 2019; Adl and Mathison 2019).

The Opisthokonta includes the arthropods, leeches, and helminths, all within the clade Metazoa (Adl and Mathison 2019). The term ‘helminth’ is not a taxonomic unit in any classification scheme, but instead a basket term for parasitic worms of humans, which is divided into four broad categories: cestodes (tapeworms), trematodes (flukes), nematodes (roundworms), and acanthocephalans (thorny-headed worms) (Adl and Mathison 2019). Leeches (Annelida), while not historically considered helminths are blood-feeding animals that will opportunistically feed on humans. Within the Metazoa are the Spiralia (acanthocephalans, annelids, cestodes, trematodes) and Ecdysozoa (arthropods and nematodes).

The cestodes are obligate parasites that usually reside in the small intestine of their definitive host. Most have multiple-host life cycles, and the definitive host becomes infected after ingestion of a larval stage encysted in the tissues of an intermediate host. Adults are long, ribbon-like organisms that have three main body regions: scolex (for attachment to the intestinal mucosa of the definitive host), neck (the base of the strobila), and the strobila (the main body, which is made of up individual segments called proglottids). Historically, cestodes that parasitize humans were divided into two categories: Pseudophyllidea (Dibothriocephalus, Adenocephalus, Diphyllobothrium), and Cyclophyllidea (Taenia, Dipylidium, Hymenolepis, several others). However, Pseudophyllidea has been abandoned in favor of two broad groups, Bothriocephalidea and Diphyllobothriidea, the latter of which contains human parasites (Kuchta et al. 2008). From the perspective of species that parasitize humans, Diphyllobothriidea are characterized by adult worms that attach to the intestine of the definitive host by means of bothria (grooves in the scolex). Eggs have an operculum and are unembryonated when shed in feces, and the infectious stage for the definitive host is the plerocercoid larva (e.g., sparganum). The Cyclophyllidea however attach to the intestine of their definitive hosts by means of four suckers and (often) a rostellum, that may be armed with hooklets or not. Eggs lack an operculum, are shed embryonated, and contain a hooked oncosphere that is immediately infectious for an intermediate host. The infectious larva is highly variable and terminology is often taxon-dependent (cysticercus, hydatid cyst, tetrathyridium, etc.) (Chervy 2002; Adl and Mathison 2019).

The trematodes that infect humans are all within Digenea and are also obligate parasites with multi-host life cycles. All parasitic species of humans have a snail as a first intermediate host, and many digeneans have second intermediate hosts or paratenic hosts that may comprise a variety of animals; in some species, infective stages are encysted in the environment, including on the surface of plants. Adults are usually hermaphroditic, apart from the schistosomes which are dioecious but live in copula. Adults have two muscular suckers, an oral sucker for attachment and feeding and a ventral sucker (acetabulum) for attachment. Infection of the human host is either by direct penetration of the cercaria larval stage (Schistosoma) or ingestion of the metacercaria larval stage in an intermediate animal host or on contaminated plants (Adl and Mathison 2019).

The acanthocephalans are zoonotic parasites in humans. While superficially similar to nematodes, they are more closely related to the rotifers, or possibly nested within Rotifera, proper (Garcia-Varela et al. 2000). Adults are large, pseudocoelomate animals that attach to the intestinal mucosa of the definitive host be means of a heavily armed proboscis. Human infection usually occurs from the ingestion of an infected intermediate or paratenic host (Mathison et al. 2016). The leeches (Annelida: Hirudinea) include blood-feeding members that will opportunistically feed on humans. Most are aquatic and attacks on humans usually come from swimming, fishing, and wading in fresh water.

The nematodes are a large and diverse group of organisms, most of which are free-living, although some major parasitic lineages are of great public health importance. Despite their diversity in nature, few species parasitize humans with any regularity. Two major clades of human parasites are Dorylaimia and Chromadoria, which vary greatly in their biology, route of transmission, and morphology. Most nematodes have six developmental stages: egg, four larval stages (L1-L4), and adult (L5); some larviparous species do not lay eggs. For most parasitic nematodes of humans, the infectious stage is the L3 larva, this fact is often called the ‘Rule of the Infective Third State’. Notable exceptions are members of the Trichinellida, for which the infectious stage is the L1 larva, and Eustrongylides for which the infectious stage is believed to be the precocious L4 (Anderson 2000). Most intestinal nematodes infect the human host after ingestion of fully embryonated eggs in food, water, or fomites contaminated with feces, or after ingestion of an infected intermediate or paratenic host. L3 larvae of some species, such as Strongyloides and the hookworms, can penetrate intact human skin during walking on contaminated soil. Filarial nematodes (Spirudida: Filarioidea) are vectored by sanguinivorous arthropods (Ash and Orihel 2007; Adl and Mathison 2019; Carroll et al. 2019).

The arthropods are the largest group of Metazoa, but relatively few species are adapted to parasitism on humans. Two main clades are the Chelicerata and Mandibulata, which can be broadly separated by the structure of their mouthparts. The Chelicerata includes the mites and ticks. The Mandibulata includes Pancrustacea, which contains the clades Crustacea (crustaceans) and Hexapoda (insects). The only parasitic crustaceans of humans are zoonotic pentastomids (tongueworms). The pancrustacean clade Hexapoda includes parasitic insects such as lice, fleas, beg bugs, triatomine (kissing) bugs, and myiasis-causing flies. Arthropods are characterized by a jointed exoskeleton containing chitin. Development is variable and can be gradual (hemimetabolous) or complete (holometabolous). Holometabolous insects have morphologically and biologically markedly different life cycles stages including larvae, pupae, and adults (Mathison and Pritt 2014; Mathison and Pritt 2015; Adl and Mathison 2019).

Here we provide an updated checklist of the parasitic protozoans, helminths, annelids, and arthropods of humans, nearly 20 years since the last such endeavor (Ashford and Crewe 2003), while providing an updated higher taxonomy based on advances in eukaryotic taxonomy (Adl et al. 2019). Taxonomy and systematics are largely ignored in the education of medical and public health professionals. There are frequent updates to taxonomic changes in Medical Parasitology (Simner 2017; Adl and Mathison 2019; Mathison and Pritt 2019; Mathison and Pritt 2020; Mathison et al. 2021), but taxonomy remains a challenging discipline in the medical and public health realms. We also provide annotations on the geographic distribution, host range, route of infection, and anatomic site of infection for human eukaryotic parasites.

Materials and methods

The bulk of this manuscript is an annotated checklist of protozoan, helminthic, annelid, and arthropod parasites reported from the human host, based on extensive literature searches through April 2021. A systematic literature search of the PubMed database (U.S. National Library of Medicine National Institutes of Health; https://www.ncbi.nlm.nih.gov/pubmed), Google Scholar (https://scholar.google.com/) and Google (https://www.google.com) was also performed using the keyword search phrases using various taxa in combination with human infection and case reports. We aimed to include all protozoan and helminthic parasites known to be reported from humans. The leeches and arthropods, however, provided a special challenge, as an exhaustive list of every sanguinivorous species that may feed on a human host would be large and beyond the scope of the audience. For the arthropods, the focus is on ectoparasites that spend prolonged time on the human host (lice, sarcoptid and demodecid mites, hard ticks, myiasis-causing flies, Tunga fleas) and visceral parasites (pentastomids). For leeches and arthropods that are short-term blood feeders or biters, such as non-Tunga fleas, soft ticks, zoonotic biting mites, bed bugs, and triatomine bugs, the focus is on those species that are commonly associated with humans and/or vector medically-important pathogens. Sanguinivorous flies (mosquitoes, black flies, deer flies, etc.) are not included, nor are those flies and other insects (e.g., cockroaches) that may passively transmit pathogens. Arthropods that are considered medically important due to envenomation, stings, or urticarial and allergic reactions are also not included.

Suprageneric taxa are listed in a hierarchal system lacking formal designations, following Adl et al. (Adl et al. 2019). Each suprageneric taxon in indicated by a series of icons (●) rather than using traditional Linnaean categories such as order, family, etc. Each taxon has one more icon than the preceding taxon in which it belongs. The number of clades presented varies based on the diversity within a given clade in relation to human parasites.

For organisms traditionally classified as protozoans (Amoebozoa, Excavates, and SAR), clades above the traditional ‘family’ level follow Adl and colleagues (Adl et al. 2019). The family-group taxa (typically ending in -idae) are presented based on the current classifications of the given organisms. For the helminths and arthropods, the organisms considered ‘true’ animals (Opisthokonta), the classification follows Adl and colleagues (Adl et al. 2019) to the level Holozoa, after which clades follow the current classifications for the given organisms. Genera within a family-group taxon, and species within each genus, are presented alphabetically.

Species, and genera for which isolates from human cases have not been characterized at the species level, have at least four bullet-points of information: 1) Geographic distribution, 2) Natural hosts, 3) Route of infection, and 4) Site in/on human host. In addition, many of the arthropods and leeches also have an additional bullet-point, 5) Vectored pathogens.

Geographic distribution. This is the known geographic distribution of a given species or genus. For widespread organisms, the distribution is presented generally (e.g., Worldwide, North America, Circumtropical). For organisms that are more geographically restricted, the information is presented at the country level.

Natural hosts. These are the hosts that are part of the parasite’s natural life cycle. For multi-host parasites, the hosts are presented in developmental order, starting with the first intermediate host and finishing with the definitive host. Hosts for species or genera with broad host ranges are presented generally (e.g., mammals, carnivores, birds), while hosts for parasites that are more host specific are presented at a more granular level (e.g., mosquitoes in the genus Anopheles).

Route of infection. This is route through which the human host becomes infected or colonized.

Site in/on human host. This is where the parasite resides in the human host, and includes both the typical site as well as common sites of ectopic infection.

Vectored pathogens. This bullet-point is for all the arthropods, except for the pentastomids and most of the myiasis-causing fly larvae, and leeches. It provides information on infectious agents (bacteria, viruses, parasites) that are pathogenic for the human host that are transmitted by the given arthropod. It includes agents that are believed to be vectored by a given arthropod in a natural setting and does not include agents that have simply been detected in an arthropod using molecular surveillance or in experimental models.

For all taxonomic levels, select synonyms are presented, especially for names that show up frequently in the literature regarding human cases.

Lastly, a list of excluded species is presented. These are species that have been reported as human parasites but are either not believed to be true parasites in the human host, represent data based on misidentifications, or are invalid names. The excluded species are presented alphabetically.

Checklist of eukaryotic human parasites

Amoebozoa Lühe, 1913, amend Cavalier-Smith, 1998

Tubulinea Smirnov et al., 2005

●● Echinamoebida Cavalier-Smith in Cavalier-Smith et al. 2004

Genus Vermamoeba Smirnov et al., 2011

Vermamoeba vermiformis (Page, 1967)

Geographic distribution. Worldwide (Scheid 2019).

Natural host. None; occurs in natural freshwater environments, surface water, soil, and biofilms. Humans are incidental hosts (Scheid 2019; Scheid et al. 2019; Siddiqui et al. 2021).

Route of infection. Presumably environmental exposure into eyes, mucus membranes, and wounds (Abedkhojasteh et al. 2013; Scheid 2019; Scheid et al. 2019).

Site in human host. Skin and soft tissues, eye (Scheid et al. 2019).

Notes. Previous records of Harmannella from human clinical specimens probably refer to this species.

●● Elardia Kang et al., 2017

●●● Euamoebida Lepşi, 1960 sensu Smirnov et al., 2011

●●●● Hartmannellidae Volkonsky, 1931

Genus Hartmannella Alexeiff, 1912

Geographic distribution. Worldwide.

Natural host. None (environmental); humans are incidental hosts (Bradbury 2014).

Route of infection. Unknown; presumed environmental exposure and contamination (Bradbury 2014).

Site in human host. Intestinal tract (Bradbury 2014).

Notes. Most extraintestinal reports of human infection with Hartmanella apply to H. vermiformis Page, which is now in the genus Vermamoeba.

● Evosea Kang et al., 2017

●● Archamoeba Cavalier-Smith, 1993 sensu Cavalier-Smith et al., 2004

●●● Entamoebida Cavalier-Smith, 1993

●●●● Entamoebidae Chatton, 1925

Genus Endolimax Kuenen & Swellengrebel, 1913

Endolimax nana (Wenyon et O’Connor, 1917)

Geographic distribution. Worldwide (Poulsen and Stensvold 2016).

Natural host. Humans (Poulsen and Stensvold 2016).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites(Poulsen and Stensvold 2016).

Site in human host. Large intestine, cecum, colon (Poulsen and Stensvold 2016).

Genus Entamoeba Casagrandi & Barbagallo, 1895

Entamoeba bangladeshi Royer et al., 2012

Geographic distribution. Southeast Asia, sub-Saharan Africa (Hooshyar et al. 2015; Ngobeni et al. 2017).

Natural host. Humans (Hooshyar et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Ali 2015).

Site in human host. Large intestine, cecum, colon (Ali 2015).

Entamoeba coli (Grassi, 1879)

Entamoeba hominis Casagrandi & Barbagallo, 1897

Entamoeba loeschi Lesage, 1908

Councilmania lafleuri Kofoid & Swezy, 1921

Geographic distribution. Worldwide (Hooshyar et al. 2015).

Natural hosts. Humans, monkeys (Hooshyar et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Ali 2015).

Site in human host. Large intestine, cecum, colon (Ali 2015).

Entamoeba chattoni Swellengrebel, 1914

Geographic distribution. Africa (Verweij et al. 2001; Hooshyar et al. 2015).

Natural hosts. Non-human primates. Zoonotic in humans (Sargeaunt et al. 1992; Hooshyar et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Sargeaunt et al. 1992).

Site in human host. Large intestine, cecum, colon (Sargeaunt et al. 1992).

Entamoeba dispar Brumpt, 1925

Geographic distribution. Worldwide (Ali 2015; Hooshyar et al. 2015).

Natural hosts. Humans, chimpanzee, baboons, macaques (Ali 2015; Hooshyar et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Ali 2015).

Site in human host. Large intestine, cecum, colon (Ali 2015).

Entamoeba gingivali s (Gros, 1849)

Amoeba buccalis Steinberg, 1862

Amoeba dentalis Grassi, 1879

Amoeba kartulis Doflein, 1901

Entamoeba maxillaris Kartulis, 1906

Entamoeba canibuccalis Smith, 1938

Endamoeba confusa Craig, 1916

Entamoeba equibuccalis Simitch, 1938

Entamoeba suigingivalis Tumka, 1959

Geographic distribution. Worldwide (Hooshyar et al. 2015).

Natural hosts. Humans, horses, pigs, cats, monkeys (Hooshyar et al. 2015).

Route of infection. Person-to-person contact (Bonner et al. 2018; Bradbury et al. 2019b).

Site in human host. Oral cavity; ectopic colonization of urogenital tract (Cembranelli et al. 2013; Bonner et al. 2018; Bradbury et al. 2019b; Dubar et al. 2020).

Entamoeba hartmanni Von Prowazek, 1912

Entamoeba histolytica, small race

Entamoeba minuta Woodcock & Penfold, 1916

Entamoeba tenuis Kuenen & Swellengrebel, 1917

Entamoeba minutissima Brug, 1917

Geographic distribution. Worldwide (Hooshyar et al. 2015).

Natural host. Humans (Hooshyar et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Ali 2015).

Site in human host. Large intestine, cecum, colon (Ali 2015).

Entamoeba histolytica Schaudinn, 1903

Amoeba coli Lösch, 1875

Amoeba dysenteriae Councilman & Lafleur, 1891

Entamoeba africana Hartmann & Von Prowazek, 1907

Entamoeba schaudinii Lesage, 1908

Entamoeba minuta Elmassian, 1909

Entamoeba nipponica Koidzumi, 1909

Entamoeba brasiliensis Aragao, 1912

Entamoeba venaticum Darling, 1915

Entamoeba caudata Carini & Reichenow, 1949

Geographic distribution. Worldwide; endemic areas of clinical amebiasis include Central and South America, Africa, Southeast Asia (Ali 2015; Shirley et al. 2018).

Natural host. Humans (Hooshyar et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites; oral-anal sex (Shirley et al. 2018).

Site in human host. Large intestine, cecum, colon; ectopic colonization of liver, skin, lungs, brain (Ali 2015; Mathison and Pritt 2018; Shirley et al. 2018).

Entamoeba moshkovskii (Tshalaia, 1941)

Entamoeba histolytica, Laredo strain

Entamoeba histolytica, Huff strain

Geographic distribution. Presumed worldwide; high areas of endemicity include Australia, India, Bangladesh, Tanzania, Pakistan, Iran (Ali 2015; Kyany’a et al. 2019).

Natural host. Humans (Hooshyar et al. 2015; Lopez et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Ali 2015).

Site in human host. Large intestine, cecum, colon (Ali 2015).

Entamoeba nuttalli (Castellani, 1908)

Loeschia duboscqi Mathis, 1913

Amoeba ateles Eichhorn & Gallagher, 1916

Loeschia cynomolgi Brug, 1923

Geographic distribution. Native to Southeast Asia, probably worldwide in zoos and from the animal trade (Tanaka et al. 2019).

Natural hosts. Non-human primates. Zoonotic in humans (Hooshyar et al. 2015; Levecke et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites.

Site in human host. Large intestine, cecum, colon (Levecke et al. 2015)

Entamoeba polecki (Von Prowazek, 1912)

Entamoeba debliecki Nieschulz, 1923

Geographic distribution. Worldwide; spots of high endemicity include Venezuela, Iran, Southeast Asia, Papua New Guinea (Verweij et al. 2001; Stensvold et al. 2018).

Natural hosts. Pigs, monkeys. Zoonotic in humans (Hooshyar et al. 2015).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Ali 2015).

Site in human host. Large intestine, cecum, colon (Ali 2015).

Genus Iodamoeba Dobell, 1919

Iodamoeba buetschlii (Von Prowazek, 1912)

Geographic distribution. Worldwide (Ash and Orihel 2007).

Natural host. Human (Ash and Orihel 2007).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Ash and Orihel 2007).

Site in human host. Large intestine, cecum, colon (Ash and Orihel 2007).

Discosea Cavalier-Smith et al., 2004

●● Flabellinia Smirnov et al., 2005

●●● Thecamoebida Schaeffer, 1926, emend. Smirnov et al., 2011

●●●● Thecamoebidae Schaeffer, 1926, emend. Smirnov et al., 2011

Genus Sappinia Dangeard, 1896

Sappinia pedata Dangeard, 1896

Geographic distribution. Presumed worldwide (Visvesvara 2013).

Natural host. None (environmental); humans are incidental hosts

Route of infection. Presumably by the entry of cysts or trophozoites through mucous membranes (e.g., nasal passages) or broken skin (Qvarnstrom et al. 2009; Visvesvara 2013).

Site in human host. Central nervous system (CNS) (Qvarnstrom et al. 2009; Visvesvara 2013).

●● Centramoebia Cavalier-Smith et al., 2016

●●● Acanthopodida Page, 1976

●●●● Acanthamoebidae Sawyer & Griffin, 1975

Genus Acanthamoeba Volonsky, 1931

Notes. Clinically, Acanthamoeba species are usually characterized by their genotypes rather than traditional Linnaean binominal nomenclature (Booton et al. 2005).

Acanthamoeba Genotype T1

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) or broken skin (Booton et al. 2005; Khan 2006).

Site in human host. CNS (Booton et al. 2005; Khan 2006).

Acanthamoeba Genotype T2

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Booton et al. 2005; Khan 2006).

Site in human host. Eye (Khan 2006).

Acanthamoeba Genotype T3

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Booton et al. 2005; Khan 2006).

Site in human host. Eye (Booton et al. 2005; Khan 2006).

Acanthamoeba Genotype T4

Geographic distribution. Worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) or broken skin (Booton et al. 2005; Khan 2006).

Site in human host. Eye, skin, lung, brain, sinus cavity, disseminated infection (Booton et al. 2005; Khan 2006).

Acanthamoeba Genotype T5

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Ledee et al. 2009).

Site in human host. Eye (Ledee et al. 2009).

Acanthamoeba Genotype T6

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Booton et al. 2005; Khan 2006).

Site in human host. Eye (Booton et al. 2005; Khan 2006).

Acanthamoeba Genotype T8

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Orosz et al. 2018).

Site in human host. Eye (Orosz et al. 2018).

Acanthamoeba Genotype T10

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) or broken skin (Booton et al. 2005; Khan 2006; Nuprasert et al. 2010).

Site in human host. CNS, eye (Booton et al. 2005; Khan 2006; Nuprasert et al. 2010).

Acanthamoeba Genotype T11

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Booton et al. 2005; Khan 2006).

Site in human host. Eye (Booton et al. 2005; Khan 2006).

Acanthamoeba Genotype T12

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) or broken skin (Booton et al. 2005; Khan 2006).

Site in human host. CNS (Booton et al. 2005; Khan 2006).

Acanthamoeba Genotype T13

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Grün et al. 2014)

Site in human host. Eye (Grün et al. 2014).

Acanthamoeba Genotype T15

Geographic distribution. Presumed worldwide (Booton et al. 2005).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) (Di Cave et al. 2009).

Site in human host. Eye (Di Cave et al. 2009).

●●●● Balamuthiidae Cavalier-Smith et al., 2004

Genus Balamuthia Visvesvara et al., 1993

Balamuthia mandrillaris Visvesvara et al., 1993

Geographic distribution. Worldwide (Visvesvara 2013; Cope et al. 2019).

Natural host. None (environmental); humans are incidental hosts.

Route of infection. Entry of environmental trophozoites or cysts through mucous membranes (e.g., eye, nasal passages) or broken skin (Visvesvara 2013; Cope et al. 2019).

Site in human host. Disseminated infection with predilection for CNS (Visvesvara 2013; Cope et al. 2019).

SAR (Stremanopiles-Alveolata-Rhizaria) Burki et al., 2008, emend. Adl et al., 2012

Stramenopiles Patterson 1989, emend. Adl et al., 2005

●● Bigyra Cavalier-Smith, 1998, emend. Cavalier-Smith et al., 2006

●●● Opalozoa Cavalier-Smith, 1991, emend. Cavalier-Smith et al., 2006

●●●● Opalinata Wenyon, 1926, emend. Cavalier-Smith, 1997

Genus Blastocystis Alexeieff, 1911

Notes. As the molecular epidemiology is becoming better understood, it is becoming less common to recognize Blastocystis by traditional Linnaean binominal nomenclature but rather by their genetic subtypes (Stensvold et al. 2007; Tan 2008).

Blastocystis subtype 1

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Various mammals. Zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 2

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Non-human primates, pigs. Zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 3

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 4

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Rodents. Zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 5

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Pigs, cattle. Zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 6

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Birds. Zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 7

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Birds. Zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 8

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Monkeys, birds. Zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 9

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Unknown; presumed zoonotic in humans (Stensvold et al. 2007; Tan 2008).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Blastocystis subtype 12

Geographic distribution. Worldwide (Stensvold et al. 2007; Tan 2008).

Natural hosts. Goats, cattle. Zoonotic in humans (Stensvold et al. 2007; Tan 2008; Udonsom et al. 2018; Jiménez et al. 2019).

Route of infection. Ingestion of cyst-forms and/or vacuolar-forms in contaminated food, water, fomites (Tan 2008).

Site in human host. Large intestine (Tan 2008).

Alveolata Cavalier-Smith, 1991

●● Colpodellida Cavalier-Smith, 1993, amend. Adel et al. 2005, 2019

●●● Colpodellidae Simpson & Patterson, 1996

Genus Colpodella Cienkowski, 1865

Geographic distribution. Worldwide (Getty et al. 2021).

Natural hosts. None; free-living predators of other protozoans. Humans are incidental hosts (Getty et al. 2021).

Route of infection. Unknown, proposed transmission via the bite of ticks in the genus Ixodes (Yuan et al. 2012; Jiang et al. 2018).

Site in human host. Blood (Yuan et al. 2012; Jiang et al. 2018).

Notes. In nature, Colpodella species are free-living predators of other protozoans. Copodella-like organisms have been diagnosed twice in patients from China, one from blood (Yuan et al. 2012) and once from CSF (Jiang et al. 2018); only the former also demonstrated morphologic evidence of a potential parasite. In both cases, the identifications were made by sequencing analyses. The species-level identification was not made in either case, and the organisms in at least one of the cases (Yuan et al. 2012) might represent an as-of-yet undescribed genus. Further work is needed to confirm the ability of Colpodella and related organisms to cause parasitic infections in humans.

●● Apicomplexa Levine, 1970, emend. Adl et al. 2005

●●● Aconoidasida Mehlhorn et al., 1980

Hematazoa Vivier, 1982

●●●● Haemospororida Danilewsky, 1885

●●●●● Plasmodiidae Mesnil, 1903

Genus Plasmodium Marchiafava & Celli, 1885

Plasmodium brasilianum Gonder et von Berenberg-Gossler, 1908

Geographic distribution. Brazil, Venezuela, Colombia , Panama, Peru (Coatney et al. 1971).

Natural hosts. Intermediate hosts are New World monkeys. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as an intermediate host (Coatney et al. 1971; Lalremruata et al. 2015).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection), blood (Coatney et al. 1971).

Notes. It has been suggested that P. brasilianum is conspecific with P. malariae and that P. malariae adapted to non-human primates in Latin America after being introduced from Africa (Guimaraes et al. 2012).

Plasmodium coatneyi Eyles et al., 1962

Geographic distribution. Peninsular Malaysia, Philippines (Coatney et al. 1971).

Natural hosts. Intermediate host is the crab-eating macaque (Macaca fascicularis). Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as an intermediate host (Coatney et al. 1971; Yap et al. 2021).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection), blood (Coatney et al. 1971).

Plasmodium cynomolgi Mayer, 1907

Geographic distribution. Southeast Asia (Coatney et al. 1971).

Natural hosts. Intermediate hosts are macaques. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as an intermediate host (Coatney et al. 1971; Hartmeyer et al. 2019; Yap et al. 2021).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection, chronic sequestration), blood (Coatney et al. 1971).

Plasmodium falciparum (Welch, 1897)

Oscillaria malariae Laveran, 1881

Haemamoeba praecox Feletti & Grassi, 1890

Haemamoeba immaculata Grassi, 1891

Haemamoeba laverani Labbe, 1894

Haemosporidium sedecimanae Lewkowicz, 1897

Haemosporidium vigesimotertianae Lewkowicz, 1897

Geographic distribution. Circumtropical; sub-Saharan Africa, Asia, Latin America, Caribbean (Snow et al. 2005; Weiss et al. 2019).

Natural hosts. Intermediate hosts are humans. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles (Coatney et al. 1971).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection), blood, CNS (cerebral malaria) (Coatney et al. 1971; Idro et al. 2010).

Plasmodium inui Helberstaedter & Von Prowazek, 1907

Geographic distribution. Southeast Asia (Coatney et al. 1971).

Natural hosts. Intermediate hosts are Old World monkeys. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as an intermediate host (Coatney et al. 1971; Yap et al. 2021).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection), blood (Coatney et al. 1971; Liew et al. 2021).

Plasmodium knowlesi Sinton & Mulligan, 1932

Geographic distribution. Southeast Asia (Coatney et al. 1971).

Natural hosts. Intermediate hosts are macaques. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as an intermediate host (Coatney et al. 1971; Singh and Daneshvar 2013; Yap et al. 2021).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection), blood (Coatney et al. 1971).

Plasmodium malariae (Grassi & Feletti, 1890)

Plasmodium quartanae Celli & Sanfelice, 1891

Haematosporidium tertianae Labbe, 1894

Geographic distribution. Sub-Saharan Africa, Southeast Asia, Indonesia, Pacific Islands, Amazonian South America (Coatney et al. 1971; Collins and Jeffery 2007).

Natural hosts. Intermediate hosts are humans; non-human primates in Latin America are reservoir hosts. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles (Coatney et al. 1971; Collins and Jeffery 2007).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971; Collins and Jeffery 2007).

Site in human host. Liver (initial infection), blood (Coatney et al. 1971; Collins and Jeffery 2007).

Plasmodium ovale curtisi Sutherland et al., 2010

Geographic distribution. Western sub-Saharan Africa, Southeast Asia (Coatney et al. 1971).

Natural hosts. Intermediate hosts are humans. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles (Coatney et al. 1971; Collins and Jeffery 2005; Oguike et al. 2011).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971; Collins and Jeffery 2005).

Site in human host. Liver (initial infection, chronic sequestration), blood (Coatney et al. 1971; Collins and Jeffery 2005).

Notes. With the separation of P. ovale into the subspecies P. ovale curtisi and P. o. wallikeri, the epidemiology of the two species in not well understood. Both subspecies are sympatric at the country level in several African countries, but their individual distributions in Southeast Asia are not well defined (Oguike et al. 2011).

Plasmodium ovale wallikeri Sutherland et al., 2010

Geographic distribution. Western sub-Saharan Africa, Southeast Asia (Coatney et al. 1971).

Natural hosts. Intermediate hosts are humans. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles (Coatney et al. 1971; Collins and Jeffery 2005; Oguike et al. 2011).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971; Collins and Jeffery 2005).

Site in human host. Liver (initial infection, chronic sequestration), blood (Coatney et al. 1971; Collins and Jeffery 2005).

Notes. With the separation of P. ovale into the subspecies P. ovale curtisi and P. o. wallikeri, the epidemiology of the two species in not well understood. Both subspecies are sympatric at the country level in several African countries, but their individual distributions in Southeast Asia are not well defined (Oguike et al. 2011).

Plasmodium schwetzi Brumpt, 1938

Geographic distribution. Tropical Africa (Coatney et al. 1971).

Natural hosts. Intermediate hosts are gorillas and chimpanzees. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as intermediate hosts (Contacos et al. 1970; Coatney et al. 1971).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection, presumed chronic sequestration), blood (Coatney et al. 1971).

Plasmodium simiovale Dissanaike, Nelson & Garnham, 1965

Geographic distribution. Sri Lanka, Malaysia (Coatney et al. 1971).

Natural hosts. Intermediate hosts is the toque macaque (Macaca sinica). Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as intermediate hosts (Coatney et al. 1971; Yap et al. 2021).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection, chronic sequestration), blood (Coatney et al. 1971; Yap et al. 2021).

Plasmodium simium Fonseca, 1951

Geographic distribution. Brazil (Coatney et al. 1971).

Natural hosts. Intermediate hosts are howler monkeys and capuchins. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles. Zoonotic in humans as intermediate hosts (Coatney et al. 1971; Brasil et al. 2017).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection, chronic sequestration), blood (Coatney et al. 1971; Brasil et al. 2017).

Notes. It has been suggested P. simium is conspecific with P. vivax, and that P. vivax adapted to non-human primates in Latin America after being introduced by humans (Daron et al. 2020).

Plasmodium vivax (Grassi & Feletii, 1890)

Haemamoeba malariae Feletti & Grassi, 1890, in part

Haemosporidium tertianae Lewkowicz, 1897

Plasmodium camarense Ziemann, 1915

Geographic distribution. Africa (east, Horn of Africa, and Madagascar), Central and South America, Central Asia, Indian Subcontinent, Southeast Asia, Korean Peninsula (Coatney et al. 1971; Howes et al. 2016).

Natural hosts. Intermediate hosts are humans; non-human primates can serve as reservoir hosts. Arthropod vector and definitive hosts are mosquitoes in the genus Anopheles (Coatney et al. 1971).

Route of infection. Introduction of sporozoites via the bite of infected Anopheles mosquito (Coatney et al. 1971).

Site in human host. Liver (initial infection, chronic sequestration), blood, CNS (Coatney et al. 1971; Sarkar and Bhattacharya 2008; Mukhtar et al. 2019).

●●●● Piroplasmorida Wenyon, 1926

●●●●● Babesiidae Poche, 1913

Genus Babesia Starcovivi, 1893

Babesia divergens M’Fadyean & Stockman, 1911

Geographic distribution. Europe (Ord and Lobo 2015)

Natural hosts. Intermediate hosts are primarily cattle. Arthropod vector and definitive hosts are ticks in the genus Ixodes, primarily I. ricinus. Zoonotic in humans as intermediate hosts (Ord and Lobo 2015; Kukina et al. 2018, 2019).

Route of infection. Introduction of sporozoites via the bite of the Ixodes tick vector; person-to-person transmission via blood and solid organ transplants (Ord and Lobo 2015; Kukina et al. 2018, 2019).

Site in human host. Blood (Ord and Lobo 2015; Kukina et al. 2018, 2019).

Babesia duncani Conrad et al., 2006

Babesia strain WA1

Babesia strain WA2

Babesia strain CA5

Babesia strain CA6

Geographic distribution. Western and northern North America (Conrad et al. 2006; Ord and Lobo 2015).

Natural hosts. Intermediate hosts are suspected as being mule deer (Odocoileus hemionus). Arthropod vector and definitive host is believed to be the tick Dermacentor albipictus. Zoonotic in humans (Swei et al. 2019).

Route of infection. Introduction of sporozoites via the bite of the presumptive tick vector; possibly also via blood transfusion and solid organ transplants (Conrad et al. 2006).

Site in human host. Blood.

Babesia microti (França, 1910)

Geographic distribution. Northeastern North America, Australia (Senanayake et al. 2012; Ord and Lobo 2015; Westblade et al. 2017).

Natural hosts. Intermediate hosts are rodents, primarily white-footed mice (Peromyscus leucopus), and deer, primarily white-tailed deer (Odocoileus virginianus). Arthropod vector and definitive hosts are ticks in the genus Ixodes, primarily I. scapularis. Zoonotic in humans as intermediate hosts (Westblade et al. 2017).

Route of infection. Introduction of sporozoites via the bite of infected tick, blood transfusion, and solid organ transplants (Ord and Lobo 2015; Westblade et al. 2017).

Site in human host. Blood (Ord and Lobo 2015; Westblade et al. 2017).

Babesia motasi Wenyoun, 1926

Babesia sp. Strain KO-1

Babesia ovis-like

Geographic distribution. Eurasia (Kim et al. 2007; Hong et al. 2019).

Natural hosts. Intermediate hosts are sheep. Definitive hosts are ticks in the genus Haemaphysalis. Zoonotic in humans as intermediate hosts (Kim et al. 2007; Hong et al. 2019; Wang et al. 2020).

Route of infection. Introduction of sporozoites via the bite of infected tick (Kim et al. 2007; Hong et al. 2019; Wang et al. 2020).

Site in human host. Blood (Hong et al. 2019).

Babesia odocoilei Emerson & Wright, 1970

Geographic distribution. Eastern North America (Pattullo et al. 2013).

Natural hosts. Intermediate hosts are cervids, primarily white-tailed deer (Odocoileus virginianus). Arthropod vector and definitive host is the tick Ixodes scapularis; birds may serve as reservoir hosts for larvae or nymphs. Zoonotic in humans as intermediate hosts (Pattullo et al. 2013; Scott et al. 2021).

Route of infection. Introduction of sporozoites via the bite of infected tick (Scott et al. 2021).

Site in human host. Blood (Scott et al. 2021).

Babesia venatorum Herwaldt et al., 2003

Babesia strain EU1

Geographic distribution. Europe (Herwaldt et al. 2003).

Natural hosts. Intermediate hosts are red deer (Cervus elaphus); roe deer, sheep, dogs, cats, and other mammals may serve as reservoir hosts. Arthropod vectors and definitive hosts are ticks in the genus Ixodes, primarily I. ricinus. Zoonotic in humans as intermediate hosts (Herwaldt et al. 2003; Gray et al. 2019).

Route of infection. Introduction of sporozoites via the bite of infected Ixodes tick; possibly also via blood transfusion and solid organ transplants (Herwaldt et al. 2003).

Site in human host. Blood (Herwaldt et al. 2003).

Babesia sp. Strain MO-1

Babesia divergens-like

Geographic distribution. Central and Pacific Northwest USA (Burgess et al. 2017).

Natural hosts. Unknown; presumed intermediate hosts are unknown and presumed arthropod vector and definitive hosts are ticks in the genus Ixodes. Zoonotic in humans as intermediate hosts (Burgess et al. 2017; Herc et al. 2018).

Route of infection. Introduction of sporozoites via the bite of infected tick; possibly also via blood transfusion and solid organ transplantation (Burgess et al. 2017; Herc et al. 2018).

Site in human host. Blood (Burgess et al. 2017; Herc et al. 2018).

Notes. This strain was originally described from Missouri, USA. It has since been described from the states of Washington, Kentucky, and Arkansas (Burgess et al. 2017). Genetically it is very similar to the Palearctic B. divergens and is often referred to as Babesia divergens-like (Herc et al. 2018).

Babesia sp. crassa -like

Geographic distribution. Undefined; human cases known from China and Slovenia (Jia et al. 2018; Strasek-Smrdel et al. 2020).

Natural hosts. Unknown; presumed intermediate hosts are sheep, goats, presumed arthropod vector and definitive hosts are ticks in the genera Haemaphysalis and/or Ixodes. Zoonotic in humans as intermediate hosts (Jia et al. 2018; Strasek-Smrdel et al. 2020).

Route of infection. Introduction of sporozoites via the bite of infected tick; possibly also via blood transfusion and solid organ transplantation (Jia et al. 2018; Strasek-Smrdel et al. 2020).

Site in human host. Blood (Jia et al. 2018; Strasek-Smrdel et al. 2020).

●●●●● Anthemosomatidae Levine, 1981

Genus Anthemosoma Landau et al., 1969

Anthemosoma garnhami Landau et al., 1969

Geographic distribution. Sub-Saharan Africa (Chavatte et al. 2018).

Natural hosts. Intermediate hosts are rodents, including spiny mice (Acomys). Arthropod vector and definitive hosts are unknown but presumed to be ixodid ticks. Zoonotic in humans (Chavatte et al. 2018; Stead et al. 2021).

Route of infection. Presumably by introduction of sporozoites via the bite of an infected tick (Stead et al. 2021).

Site in human host. Blood (Stead et al. 2021).

●●● Conoidasida Levine, 1988

●●●● Coccidia Leuckart, 1879

●●●●● Eimeriorina Léger, 1911

●●●●●● Eimeriidae Minchin, 1903

Genus Cyclospora Schneider, 1881

Cyclospora cayetanensis Ortega et al., 1994

Geographic distribution. Nearly worldwide, hot spots of endemicity include Latin America, the Caribbean, Middle East, and Southeast Asia (Ortega and Sanchez 2010; Almeria et al. 2019).

Natural host. Human (Ortega and Sanchez 2010; Almeria et al. 2019).

Route of infection. Ingestion of sporulated oocysts in fecally contaminated produce and water (Ortega and Sanchez 2010; Cama and Mathison 2015; Almeria et al. 2019).

Site in human host. Small intestine (Ortega and Sanchez 2010; Almeria et al. 2019).

●●●●●● Sarcocystidae Poche, 1913

Genus Cystoisospora Frenkel, 1977

Cystoisospora belli (Wenyon, 1923)

Geographic distribution. Nearly worldwide, more prevalent in tropics and subtropics (Cama and Mathison 2015; Dubey and Almeria 2019).

Natural host. Human (Cama and Mathison 2015; Dubey and Almeria 2019).

Route of infection. Ingestion of sporulated oocysts in fecally contaminated water, food, fomites (Cama and Mathison 2015; Dubey and Almeria 2019)

Site in human host. Small intestine (Cama and Mathison 2015; Dubey and Almeria 2019; Rowan et al. 2020)

Genus Sarcocystis Lankester, 1882

Sarcocystis heydorni Dubey et al., 2015

Geographic distribution. Europe, China (Dubey et al. 2015).

Natural hosts. Cattle are intermediate hosts. Humans are the definitive hosts (Dubey 2015; Dubey et al. 2015).

Route of infection. Ingestion of cysts (bradyzoites) in undercooked beef (Dubey 2015; Dubey et al. 2015).

Site in human host. Small intestine (Dubey 2015; Dubey et al. 2015)

Sarcocystis hominis (Railiet & Lucet, 1891)

Sarcocystis bovihominis Heydorn et al., 1975

Geographic distribution. Nearly worldwide, more prevalent in tropics and subtropics (Dubey 2015).

Natural hosts. Intermediate hosts are cattle. Definitive hosts are humans and non-human primates (Fayer 2004; Dubey 2015; Fayer et al. 2015).

Route of infection. Ingestion of cysts (bradyzoites) in undercooked beef (Fayer 2004; Dubey 2015; Fayer et al. 2015).

Site in human host. Small intestine (Fayer 2004; Dubey 2015; Fayer et al. 2015).

Sarcocystis nesbitti Mandour, 1969

Geographic distribution. Southeast Asia (Abubakar et al. 2013; Fayer et al. 2015).

Natural hosts. Unknown. Natural intermediate host is unknown, non-human primates can serve as intermediate or reservoir hosts. Definitive hosts are presumed to be snakes or other reptiles. Zoonotic in humans as incidental intermediate hosts (Abubakar et al. 2013).

Route of infection. Ingestion of fully-sporulated oocysts in contaminated food, water, fomites (Abubakar et al. 2013; Fayer et al. 2015).

Site in human host. Skeletal muscle (Abubakar et al. 2013; Fayer et al. 2015).

Sarcocystis suihominis Heydorn, 1977

Geographic distribution. Nearly worldwide, more prevalent in tropics and subtropics (Dubey 2015).

Natural hosts. Intermediate hosts are pigs. Definitive hosts are humans and non-human primates (Fayer 2004; Dubey 2015; Fayer et al. 2015).

Route of infection. Ingestion of cysts (bradyzoites) in undercooked pork (Fayer 2004; Dubey 2015; Fayer et al. 2015).

Site in human host. Small intestine (Fayer 2004; Dubey 2015; Fayer et al. 2015).

Genus Toxoplasma Nicolle & Manceaux, 1909

Toxoplasma gondii (Nicolle & Manceaus, 1908)

Geographic distribution. Worldwide (Robert-Gangneux and Darde 2012).

Natural hosts. Wild and domestic felids. Many mammals and birds can serve as reservoir hosts; zoonotic in humans as dead-end hosts (Attias et al. 2020).

Route of infection. Ingestion of fully sporulated oocysts in food, water, fomites contaminated with cat feces; ingestion of cysts (bradyzoites) in infected paratenic hosts; blood transfusion or solid organ transplantation; transplacentally from mother to fetus (Montoya and Remington 2008; Robert-Gangneux and Darde 2012; Attias et al. 2020).

Site in human host. Disseminated infection, common sites are skeletal muscle, myocardium, brain, and eyes; can be transmitted transplacentally from mother to fetus (Montoya and Remington 2008; Robert-Gangneux and Darde 2012).

●●●● Gregarinasina Dufour, 1828

●●●●● Cryptogregarinorida Cavalier-Smith, 2014, emend. Adl et al., 2019

●●●●●● Cryptosporidiidae Leger, 1911

Genus Cryptosporidium Tyzzer, 1910

Cryptosporidium andersoni Lindsay et al., 2000

Geographic distribution. Worldwide (Feng et al. 2011).

Natural hosts. Cattle, camels, sheep, goats, horses. Zoonotic in humans (Feng et al. 2011; Liu et al. 2015).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with animal feces (Jiang et al. 2014).

Site in human host. Unknown, presumed stomach.

Cryptosporidium bovis Barker & Carbonell, 1974

Geographic distribution. Worldwide (Feng et al. 2007).

Natural hosts. Cattle. Zoonotic in humans (Ng et al. 2012; Das et al. 2019).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with cattle feces (Ng et al. 2012; Das et al. 2019).

Site in human host. Duodenum and small intestine.

Cryptosporidium canis Fayer et al., 2001

Geographic distribution. Worldwide (Fayer et al. 2001).

Natural hosts. Dogs. Zoonotic in humans (Fayer et al. 2001; Ryan et al. 2016).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with dog feces (Fayer et al. 2001; Ryan et al. 2016).

Site in human host. Duodenum and small intestine

Cryptosporidium cuniculus Inman & Takeuchi, 1979

Geographic distribution. Undefined, most human cases from Europe and Australia (Koehler et al. 2014; Puleston et al. 2014).

Natural hosts. Rabbits, kangaroos. Zoonotic in humans (Koehler et al. 2014; Puleston et al. 2014).

Route of infection. Ingestion of sporulated oocysts water, food, fomites contaminated with rabbit/animal feces (Koehler et al. 2014; Puleston et al. 2014; Ryan et al. 2016).

Site in human host. Duodenum and small intestine.

Cryptosporidium ditrichi Čondlová et al., 2018

Geographic distribution. Europe (Condlova et al. 2018).

Natural hosts. Field mice (Apodemus spp.). Zoonotic in humans (Condlova et al. 2018; Beser et al. 2020).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with rodent feces (Beser et al. 2020; Condlova et al. 2018).

Site in human host. Duodenum and small intestine

Cryptosporidium erinacei Kváč et al., 2014

Cryptosporidium hedgehog genotype

Geographic distribution. Europe (Kváč et al. 2014).

Natural hosts. Hedgehogs, horses. Zoonotic in humans (Kváč et al. 2014; Zahedi et al. 2016).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with animal feces (Kváč et al. 2014; Zahedi et al. 2016).

Site in human host. Duodenum and small intestine

Cryptosporidium fayeri Ryan et al., 2008

Geographic distribution. Australia (Ryan et al. 2008; Waldron et al. 2010).

Natural hosts. Marsupials. Zoonotic in humans (Waldron et al. 2010).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with marsupial feces (Waldron et al. 2010).

Site in human host. Duodenum and small intestine

Cryptosporidium felis Iseki, 1979

Geographic distribution. Worldwide (Jiang et al. 2020).

Natural hosts. Cats, foxes, horses, cattle. Zoonotic in humans (Caccio et al. 2002; Jiang et al. 2020).

Route of infection. Ingestion of sporulated oocysts in fecally contaminated water, food, fomites contaminated with cat/animal feces (Caccio et al. 2002; Jiang et al. 2020).

Site in human host. Duodenum and small intestine

Cryptosporidium hominis Morgan-Ryan et al., 2002

Geographic distribution. Worldwide (Cama and Mathison 2015).

Natural hosts. Humans, non-human primates (Cama and Mathison 2015; Ryan et al. 2016; Chen et al. 2019).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with human feces (Cama and Mathison 2015).

Site in human host. Duodenum and small intestine, disseminated infections in immunocompromised patients (Bouzid et al. 2013; Cama and Mathison 2015).

Cryptosporidium meleagridis Slavin, 1955

Geographic distribution. Worldwide

Natural hosts. Birds. Zoonotic in humans (Akiyoshi et al. 2003).

Route of infection. Ingestion of sporulated oocysts in fecally contaminated water, food, fomites contaminated with bird feces (Akiyoshi et al. 2003).

Site in human host. Duodenum and small intestine, disseminated infections in immunocompromised patients (Akiyoshi et al. 2003; Kopacz et al. 2019).

Cryptosporidium muris Tyzzer, 1910

Geographic distribution. Worldwide (Chappell et al. 2015).

Natural hosts. Rodents, ruminants, horses, non-human primates, carnivores. Zoonotic in humans (Chappell et al. 2015).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with animal feces (Chappell et al. 2015).

Site in human host. Unknown, presumed stomach (Chappell et al. 2015).

Cryptosporidium occultus Kváč et al., 2018

Cryptosporidium parvum VF383

Geographic distribution. Worldwide (Kvac et al. 2018).

Natural hosts. Rodents. Zoonotic in humans (Kvac et al. 2018; Xu et al. 2020).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with rodent feces (Kvac et al. 2018; Xu et al. 2020).

Site in human host. Duodenum and small intestine

Cryptosporidium parvum Tyzzer, 1912

Geographic distribution. Worldwide (Cama and Mathison 2015; Ryan et al. 2016).

Natural hosts. Cattle, sheep, goats, and other ruminants, rodents. Zoonotic in humans (Cama and Mathison 2015; Ryan et al. 2016).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with human and animal feces (Cama and Mathison 2015; Ryan et al. 2016).

Site in human host. Duodenum and small intestine, disseminated infections in immunocompromised patients (Cama and Mathison 2015; Ryan et al. 2016).

Cryptosporidium ryanae Fayer et al., 2008

Cryptosporidium deer-like genotype

Geographic distribution. XX (Fayer et al. 2008).

Natural hosts. Cattle. Zoonotic in humans (Chako et al. 2010; Das et al. 2019).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with cattle feces (Das et al. 2019).

Site in human host. Duodenum and small intestine.

Cryptosporidium scrofarum Kváč et al., 2013

Cryptosporidium pig genotype II

Geographic distribution. Worldwide (Kváč et al. 2013).

Natural hosts. Pigs. Zoonotic in humans (Ryan et al. 2016).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with pig feces (Ryan et al. 2016).

Site in human host. Duodenum and small intestine.

Cryptosporidium suis Ryan et al., 2004

Geographic distribution. Worldwide (Ryan et al. 2004).

Natural hosts. Pigs. Zoonotic in humans (Xiao et al. 2002).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with pig feces (Xiao et al. 2002; Nemejc et al. 2013)

Site in human host. Duodenum and small intestine

Cryptosporidium tyzzeri Ren et al., 2012

Cryptosporidium mouse genotype I

Geographic distribution. Presumed worldwide (Raskova et al. 2013).

Natural hosts. Rodents, horses may serve as reservoir hosts. Zoonotic in humans (Raskova et al. 2013; Wagnerová et al. 2015).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with rodent feces (Raskova et al. 2013).

Site in human host. Duodenum and small intestine

Cryptosporidium ubiquitum Fayer et al., 2010

Cryptosporidium cervine genotype

Geographic distribution. Worldwide (Li et al. 2014).

Natural hosts. Many mammal species, including ruminants, rodents, and carnivores; presumed zoonotic in humans (Li et al. 2014).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with animal feces (Li et al. 2014).

Site in human host. Duodenum and small intestine

Cryptosporidium viatorum Elwin et al., 2012

Geographic distribution. Worldwide (Koehler et al. 2018).

Natural hosts. Rodents. Zoonotic in humans (Koehler et al. 2018).

Route of infection. Ingestion of sporulated oocysts in water, food, fomites contaminated with rodent and human feces (Koehler et al. 2018).

Site in human host. Duodenum and small intestine.

●● Ciliophora Doflein, 1901

●●● Postodesmatophora Gerassimova & Seravin, 1976

●●●● SAL (Spirotrichea-Lamellicorticata-Armophorea) Gentekaki et al., 2014

●●●●● Litostomatea Small & Lynn, 1981

●●●●●● Trichostomatia Bütschli, 1889

●●●●●●● Balantidiidae Reichenow in Doflein & Reichenow, 1929

Genus Balantioides Alexeieff, 1931

Neobalantidium Pomajbíková et al., 2013

Balantioides coli (Malmsten, 1857)

Geographic distribution. Worldwide; high areas of endemicity include the Altiplano region of Bolivia, Philippines, New Guinea, Middle East (Schuster and Ramirez-Avila 2008).

Natural hosts. Pigs, rodents. Zoonotic in humans (Schuster and Ramirez-Avila 2008).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Schuster and Ramirez-Avila 2008).

Site in human host. Large intestine (Schuster and Ramirez-Avila 2008).

Excavates Cavalier-Smith, 2002, emend. Simpson, 2003

Metamonada Grassé, 1952

●● Fornicata Simpson, 2003

●●● Diplomonadida Wenyon, 1926

●●●● Hexamitidae Kent, 1880

Genus Enteromonas da Fonseca, 1915

Enteromonas hominis da Fonseca, 1915

Tricercomonas intestinalis Wenyon et O’Connor, 1917

Geographic distribution. Worldwide (Ash and Orihel 2007).

Natural host. Humans (Ash and Orihel 2007).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Spriegel et al. 1989; Ash and Orihel 2007).

Site in human host. Large intestine (Ash and Orihel 2007).

Genus Giardia Künstler, 1882

Giardia duodenalis Stiles, 1902

Cercomonas intestinalis Lambl, 1859

Giardia lamblia Kofoid & Christiansen, 1915

Giardia enterica Kofoid & Christiansen, 1920

Geographic distribution. Worldwide (Adam 2001; Cama and Mathison 2015).

Natural hosts. Two genetic assemblages implicated in human disease: A and B. Both have been found in humans and numerous non-human mammals and birds (Ryan and Caccio 2013; Heyworth 2016).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites; sexual transmission via oral-anal route (Adam 2001; Escobedo et al. 2014; Cama and Mathison 2015).

Site in human host. Duodenum, small intestine (Adam 2001; Cama and Mathison 2015).

●●● Retortamonadida Grassé, 1952

●●●● Retortamonadidae Wenrich, 1932

Genus Chilomastix Alexeieff, 1912

Chilomastix mesnili (Wenyon, 1910)

Geographic distribution. Worldwide (Ash and Orihel 2007).

Natural hosts. Humans, non-human primates (Ash and Orihel 2007).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Morimoto et al. 1996; Ash and Orihel 2007).

Site in human host. Large intestine (Ash and Orihel 2007).

Genus Retortamonas Grassi, 1879

Retortamonas intestinalis (Wenyon et O’Connoer, 1917)

Geographic distribution. Worldwide (Ash and Orihel 2007).

Natural host. Humans (Ash and Orihel 2007).

Route of infection. Ingestion of mature cysts in fecally contaminated water, food, fomites (Mendez et al. 2002; Ash and Orihel 2007).

Site in human host. Large intestine (Ash and Orihel 2007).

●● Parabasalia Honigberg, 1973

●●● Trichonomadida Kirby, 1947

●●●● Monocercomonadidae Kirby, 1944

Genus Dientamoeba Jepps & Dobell, 1918

Dientamoeba fragilis Jepps & Dobell, 1918

Geographic distribution. Worldwide (Stark et al. 2016).

Natural hosts. Humans, non-human primates, pigs (Stark et al. 2016).

Route of infection. Ingestion of trophozoites in fecally contaminated water, food, fomites. A putative cyst stage has been described, but it is not yet widely accepted among protozoologists (Munasinghe et al. 2013; Stark et al. 2014, 2016).

Site in human host. Large intestine (Stark et al. 2016).

●●●● Trichomonadidae Chalmers & Pekkola, 1918, emend. Hampl et al., 2004

Genus Pentatrichomonas Mensil, 1914

Pentatrichomonas hominis (Davaine, 1860)

Geographic distribution. Worldwide (Ash and Orihel 2007).

Natural hosts. Humans, non-human primates, dogs, cats, foxes, rabbits, cattle, sheep, goats, deer (Li et al. 2016, 2017, 2018).

Route of infection. Ingestion of trophozoites in fecally contaminated fomites (Ash and Orihel 2007).

Site in human host. Large intestine (Ash and Orihel 2007).

Genus Trichomonas Donné, 1837

Trichomonas tenax (Müller, 1773)

Geographic distribution. Worldwide (Dubar et al. 2020).

Natural host. Humans (Dubar et al. 2020).

Route of infection. Direct person-to-person contact (Dubar et al. 2020).

Site in human host. Oral cavity; ectopic colonization of pleural cavity (Bellanger et al. 2008; Marty et al. 2017; Dubar et al. 2020).

Trichomonas vaginalis (Donné, 1836)

Geographic distribution. Worldwide (Schwebke and Burgess 2004; Kissinger 2015).

Natural host. Humans (Schwebke and Burgess 2004; Kissinger 2015).

Route of infection. Sexual contact (Schwebke and Burgess 2004; Kissinger 2015).

Site in human host. Urogenital tract; rare ectopic colonization of CSF (Schwebke and Burgess 2004; Hamilton et al. 2018).

Genus Tritrichomonas Kofoid, 1920

Tritrichomonas foetus Reidmüller, 1928

Trichomonas suis Gruby & Delafond, 1843

Geographic distribution. Worldwide (Suzuki et al. 2016).

Natural host. Cattle, pigs, cats. Zoonotic and opportunistic in immunocompromised humans (Maritz et al. 2014; Yao and Köster 2015; Suzuki et al. 2016).

Route of infection. Unknown.

Site in human host. Respiratory tract, CNS, urogenital tract (Duboucher et al. 2006; Zalonis et al. 2011; Suzuki et al. 2016).

Genus Tetratrichomonas Parisi, 1910

Tetratrichomonas sp. cf. gallinarum

Geographic distribution. Unknown, presumed worldwide

Natural host. Unknown, presumed birds. Zoonotic in humans (Mantini et al. 2009; Maritz et al. 2014).

Route of infection. Unknown

Site in human host. Respiratory tract, possibly associated with bacterial infection (Mantini et al. 2009; Maritz et al. 2014).

Notes. This species has yet to be formally described. It was first isolated from pleural fluid in a patient with empyema. Bacterial cultures of the pleural fluid grew two Streptococcus species and Prevotella (Mantini et al. 2009). The protozoan may have been associated with bacteria and not an agent of human disease.

Tetratrichomonas sp. (undescribed species)

Tetratrichomonas empyemagena Lopez-Escamilla et al., 2013

Geographic distribution. Unknown, presumed worldwide

Natural hosts. Unknown

Route of infection. Unknown

Site in human host. Respiratory tract (Lopez-Escamilla et al. 2013)

Notes. This species was reported from two patients from Mexico(Lopez-Escamilla et al. 2013). The species was originally named T. empyemagena, but because it was not described under the criteria of the ICZN, it name should be considered nomen nudum. This isolate might be conspecific with that described by Mantini et al. (2009).

●●●● Simplicimonadidae Čepička et al., 2010

Genus Simplicimonas Čepička et al., 2010

Simplicimonas similis Čepička et al., 2010

Geographic distribution. Undefined, possibly worldwide (Dimasuay et al. 2013).

Natural hosts. Several vertebrates; previously recorded from lizards, cattle, and chickens (Dimasuay et al. 2013).

Route of infection. Unknown.

Site in human host. Intestinal tract (Greigert et al. 2018).

Notes. Simplicimonas similis was detected by molecular methods in four human patients in Madagascar (Greigert et al. 2018). The authors acknowledged that the parasite was not detected by microscopy and the finding may be based on spurious passage after consuming insects or another host, and further studies are required to determine if humans can serve as a reliable host (Greigert et al. 2018).

● Discoba Simpson in Hampl et al., 2009

●● Heterolobosea Page & Blanton, 1985

●●● Tetramitia Cavalier-Smith, 1993

●●●● Vahlkampfiidae Jollos, 1917

Genus Naegleria Alexeieff, 1912

Naegleria fowleri Carter, 1970

Geographic distribution. Worldwide (Gharpure et al. 2020).

Natural host. None (environmental); humans are incidental hosts (Visvesvara 2013).

Route of infection. Exposure to trophozoites and cysts in contaminated freshwater via the nasal cavity; improper use of nasal irrigation devices (Yoder et al. 2012; Visvesvara 2013).

Site in human host. CNS (Visvesvara 2013; Yoder et al. 2012; Mathison and Pritt 2018).

Genus Paravahlkampfia Brown et de Jonckheere, 1999

Paravahlkampfia francinae Visvesvara et al., 2009

Geographic distribution. Unknown (single case from Ohio, USA) (Visvesvara et al. 2009).

Natural host. None (environmental); humans are incidental hosts (Visvesvara et al. 2009).

Route of infection. Unknown; presumed environmental exposure.

Site in human host. CNS (Visvesvara et al. 2009).

Genus Tetramitus Perty, 1852

Tetramitus entericus (Page, 1974)

Geographic distribution. Worldwide (Brown and De Jonckheere 1999).

Natural host. None (environmental); humans are incidental hosts (Walochnik et al. 2000).

Route of infection. Presumed environmental exposure.

Site in human host. Eye (Walochnik et al. 2000).

Tetramitus jugosus (Page, 1967)

Geographic distribution. Worldwide (Enzien et al. 1989).

Natural host. None (environmental); humans are incidental hosts (Dua et al. 1998).

Route of infection. Presumed environmental exposure (Dua et al. 1998).

Site in human host. Eye (Dua et al. 1998).

Genus Vahlkampfia Chatton et Lalung-Bonnaire, 1912

Geographic distribution. Worldwide (Walochnik et al. 2000).

Natural host. None (environmental); humans are incidental hosts (Walochnik et al. 2000).

Route of infection. Unknown; presumed environmental exposure.

Site in human host. Eye (Walochnik et al. 2000).

Notes. Most reports of Vahlampfia from human clinical specimens are not characterized at the species level and may represent species currently assigned to other genera such as Tetramitus, Allovahlkampfia, and Paravahlkampfia.

●●●● Acrasidae Poche, 1913

Genus Allovahlkampfia Walochnik & Mulec, 2009

Allovahlkampfia spelaea Walochnik & Mulec, 2009

Geographic distribution. Not fully known; described from caves in Slovenia with single human case from Egypt (Walochnik 2009; Tolba et al. 2016).

Natural host. None (environmental); humans are incidental hosts (Tolba et al. 2016).

Route of infection. Unknown; presumed environmental exposure.

Site in human host. Eye (Tolba et al. 2016).

●● Euglenozoa Cavalier-Smith, 1981, emend. Simpson, 1997

●●● Kinetoplastea Honigberg, 1963

●●●● Metakinetoplastina Vickerman in Moreira et al., 2004

●●●●● Trypanosomatida Kent 1880, emend. Vickerman in Moreira et al. 2004

●●●●●● Trypanosomatidae Doflein, 1901

Genus Crithidia Léger, 1902

Geographic distribution. Worldwide (McGhee and Cosgrove 1980).

Natural hosts. Arthropods, mainly insects. Zoonotic in humans (McGhee and Cosgrove 1980).

Route of infection. Introduction of promastigotes via the bite of infected arthropod vector (Ghobakhloo et al. 2019; Maruyama et al. 2019).

Site in human host. Skin, bone marrow (Ghobakhloo et al. 2019; Maruyama et al. 2019).

Notes. Crithidia isolates from human clinical specimens have yet to be characterized at the species level. To date, cases are known from Brazil (Maruyama et al. 2019) and Iran (Ghobakhloo et al. 2019). The vectors in the human cases are also unknown.

Genus Endotrypanum Mesnil & Brimont, 1908

Endotrypanum colombiensis (Kreuter et al., 1991)

Geographic distribution. Colombia (Kreutzer et al. 1991).

Natural hosts. Mammalian hosts are sloths; zoonotic in humans. Arthropod vectors are sand flies in the genus Lutzomyia (Kreutzer et al. 1991).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Kreutzer et al. 1991).

Site in human host. Skin (Kreutzer et al. 1991)

Endotrypanum equatoriensis (Grimaldi-Junior et al., 1992)

Geographic distribution. Colombia, Ecuador (Grimaldi Junior et al. 1992).

Natural hosts. Mammalian hosts are sloths and squirrels; zoonotic in humans. Arthropod vectors are sand flies in the genus Lutzomyia (Grimaldi Junior et al. 1992).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Grimaldi Junior et al. 1992).

Site in human host. Skin (Grimaldi Junior et al. 1992).

Genus Leishmania Ross, 1903

Euleishmania Cupolillo et al., 2000

Subgenus Leishmania Ross, 1903

Leishmaniai (L .) aethiopica Bray et al., 1973

Geographic distribution. Africa (Ethiopia, Kenya, Uganda), Yemen (van Henten et al. 2018).

Natural hosts. Mammalian hosts include humans, rock hyraxes, and other wild mammals. Arthropod vectors are sand flies in the genus Phlebotomus, mainly P. longipes and P. pedifer (Bray et al. 1973).

Route of infection. Introduction of promastigotes via the bite of infected Phlebotomus sand fly (van Henten et al. 2018).

Site in human host. Skin (van Henten et al. 2018).

Leishmania (L.) amazonensis Lainson & Shaw, 1972

Leishmania garnhami Scorza et al., 1978

Geographic distribution. Amazonian South America (Brazil, Venezuela, Bolivia) (Torres-Guerrero et al. 2017).

Natural hosts. Mammals and birds, including humans, rodents, dogs, chickens. Arthropod vectors are sand flies in the genus Lutzomyia (Torres-Guerrero et al. 2017; Valdivia et al. 2017).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Torres-Guerrero et al. 2017; Valdivia et al. 2017).

Site in human host. Skin, mucosal membranes of nose, throat, and mouth (Torres-Guerrero et al. 2017).

Leishmania (L.) donovani (Laveran & Mesnil, 1903)

Leishmania archibaldi Castellani & Chalmers, 1919

Geographic distribution. Indian subcontinent, China, Central Africa; hot spots of endemicity include India, Bangladesh, Nepal, Sudan (Lukes et al. 2007; Ready 2014).

Natural hosts. Mammalian hosts include humans, dogs, foxes, marsupials, and rodents. Arthropod vectors are sand flies in the genera Phlebotomus (Old World) and Lutzomyia (New World) (Lukes et al. 2007; Ready 2014).

Route of infection. Introduction of promastigotes via the bite of infected sand fly (Torres-Guerrero et al. 2017).

Site in human host. Skin, spleen, liver, small intestine, lymph nodes (Torres-Guerrero et al. 2017).

Leishmania (L.) infantum Nicolle, 1908

Leishmania chagasi da Cunha & Chagas, 1937

Geographic distribution. Mediterranean Europe and Africa, southeastern Europe, Middle East, Central Asia, Central and South America (Mexico, Venezuela, Brazil, Bolivia) (Pratlong et al. 2013; Steverding 2017).

Natural hosts. Mammalian hosts include dogs, cats, foxes, lagomorphs, rodents, marsupials, and others; zoonotic in humans. Arthropod vectors are sand flies in the genera Phlebotomus (Old World) and Lutzomyia (New World) (Millan et al. 2014).

Route of infection. Introduction of promastigotes via the bite of infected sand fly (Torres-Guerrero et al. 2017).

Site in human host. Skin, spleen, liver, small intestine, lymph nodes (Torres-Guerrero et al. 2017).

Leishmania (L.) major Yakimoff & Schokhor, 1914

Geographic distribution. Northern and Central Africa, Middle East, India, China (Guerrant et al. 2006; Steverding 2017).

Natural hosts. Humans; gerbils and birds may serve as reservoir hosts; dogs can become infected but are not adequate reservoir hosts for human disease. Arthropod vectors are sand flies in the genus Phlebotomus (Al-Bajalan et al. 2018).

Route of infection. Introduction of promastigotes via the bite of infected Phlebotomus sand fly (Torres-Guerrero et al. 2017).

Site in human host. Skin (Torres-Guerrero et al. 2017).

Leishmania (L.) mexicana Biagi, 1953, emend. Garnham, 1962

Leishmania pifanoi Medina & Romero, 1962

Geographic distribution. Texas, Mexico, Belize, Guatemala, Brazil, Ecuador, Peru, Venezuela (Steverding 2017).

Natural hosts. Mammalian hosts include humans, dogs, rodents, and bats. Arthropod vectors are sand flies in the genus Lutzomyia (Berzunza-Cruz et al. 2015).

Route of infection. Introduction of promastigotes via the bite of infected sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (L.) tropica Wright, 1903

Geographic distribution. North and Central Africa, Middle East, Central Asia, India (Steverding 2017).

Natural hosts. Mammalian hosts include humans, rock hyraxes, gundi, and dogs (although dogs are not an adequate reservoir host for human disease). Arthropod vectors are sand flies in the genus Phlebotomus (Ajaoud et al. 2013).

Route of infection. Introduction of promastigotes via the bite of infected sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (L.) venezuelensis (Bonfante-Garrido, 1980)

Geographic distribution. Venezuela, northern South America (Steverding 2017).

Natural hosts. Mammalian hosts include humans, cats. Arthropod vectors are sand flies in the genus Lutzomyia (Rivas et al. 2018).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (L .) waltoni Shaw et al., 2015

Geographic distribution. Dominican Republic (Shaw et al. 2015).

Natural hosts. Mammalian hosts unknown, rats may serve as reservoir hosts; presumed zoonotic in humans. Arthropod vectors are sand flies in the genus Lutzomyia (Shaw et al. 2015).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Shaw et al. 2015).

Site in human host. Skin (Shaw et al. 2015).

Subgenus Mundinia Shaw et al. in Espinosa et al., 2016

Leishmania (M.) martiniquensis Desbois et al., 2014

Geographic distribution. Martinique, Thailand (Desbois et al. 2014; Pothirat et al. 2014).

Natural hosts. Mammalian hosts are humans. Rats may serve as reservoir hosts. Arthropod vectors are sand flies, possibly in the genera Sergentomyia (Old World) and Lutzomyia (New World) (Leelayoova et al. 2017).

Route of infection. Introduction of promastigotes via the bite of infected sand fly

Site in human host. Skin, mucosal membranes of nose, throat, and mouth (Desbois et al. 2014; Liautaud et al. 2015).

Leishmania (M.) orientalis Jariyapan et al., 2018

Leishmania siamensis Sukmee et al., 2008

Geographic distribution. Thailand (Sukmee et al. 2008; Jariyapan et al. 2018).

Natural hosts. Mammalian hosts are humans. Arthropod vectors are sand flies. (Sukmee et al. 2008; Jariyapan et al. 2018).

Route of infection. Introduction of promastigotes via the bite of infected sand fly (genus unknown).

Site in human host. Skin (Sukmee et al. 2008; Jariyapan et al. 2018).

Subgenus Sauroleishmania Ranque, 1973

Leishmania (S.) tarentolae Weynon, 1921

Geographic distribution. North Africa, southern Europe, Middle East (Klatt et al. 2019).

Natural hosts. Definitive hosts are lizards. Arthropod vectors are sand flies in the genus Sergentomyia. Zoonotic in humans (Klatt et al. 2019).

Route of infection. Introduction of promastigotes in bite of infected Sergentomyia sand fly (Klatt et al. 2019; Pombi et al. 2020).

Site in human host. Blood (Pombi et al. 2020).

Notes. The single human case was diagnosed by molecular detection (only) in blood (Pombi et al. 2020).

Subgenus Viannia Lainson & Shaw, 1987

Leishmania (V.) braziliensis Vianna, 1911

Geographic distribution. Amazonian South America (Brazil, Bolivia, Venezuela, Peru), Guatemala (Castro et al. 2007; Steverding 2017).

Natural hosts. Mammalian hosts include humans, dogs, rodents, and marsupials. Arthropod vectors are sand flies in the genus Lutzomyia (Castro et al. 2007).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin, mucosal membranes of nose, throat, and mouth (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (V.) guyanensis Floch, 1954

Geographic distribution. Northern South America (French Guiana, Suriname, Brazil, Bolivia) (Guerra et al. 2011; Steverding 2017).

Natural hosts. Mammalian hosts include sloths, anteaters, rodents, marsupials, and humans. Arthropod vectors are sand flies in the genus Lutzomyia (Guerra et al. 2011).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin, mucosal membranes of nose, throat, and mouth (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (V.) lainsoni Silveira et al., 1987

Geographic distribution. Brazil, Bolivia, Ecuador, Peru, Suriname, French Guiana (Kato et al. 2016; Mans et al. 2017; Steverding 2017).

Natural hosts. Mammalian host is lowland paca; zoonotic in humans. Arthropod vectors are sand flies in the genus Lutzomyia (Mans et al. 2017).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (V .) lindenbergi Silveira et al., 2002

Geographic distribution. Brazil (Cantanhêde et al. 2019).

Natural hosts. Mammalian hosts unknown; presumed zoonotic in humans. Arthropod vectors are sand flies in the genus Lutzomyia (Cantanhêde et al. 2019).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (V.) naiffi Lainson & Shaw, 1989

Geographic distribution. Brazil, Bolivia, Peru (Lainson and Shaw 1989; Fagundes-Silva et al. 2015).

Natural hosts. Mammalian hosts are armadillos; zoonotic in humans. Arthropod vectors are sand flies in the genus Lutzomyia (Lainson and Shaw 1989; Fagundes-Silva et al. 2015).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (V.) panamensis Lainson & Shaw, 1972

Geographic distribution. Central and South America (Steverding 2017; Torres-Guerrero et al. 2017).

Natural hosts. Mammalian hosts include sloths, procyonids, rodents, humans, and non-human primates. Arthropod vectors are sand flies in the genus Lutzomyia (Steverding 2017; Torres-Guerrero et al. 2017).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin, mucosal membranes of nose, throat, and mouth (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (V.) peruviana Velez, 1913

Geographic distribution. Peru, Bolivia (Steverding 2017; Torres-Guerrero et al. 2017).

Natural hosts. Mammalian hosts include humans, rodents, marsupials, and domestic dogs. Arthropod vectors are sand flies in the genera Lutzomyia and possibly Pintomyia (Kato et al. 2021).

Route of infection. Introduction of promastigotes via the bite of infected sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin, mucosal membranes of nose, throat, and mouth (Steverding 2017; Torres-Guerrero et al. 2017).

Leishmania (V.) shawi Lainson et al., 1989

Geographic distribution. Brazil (Lainson et al. 1989)

Natural hosts. Mammalian hosts include non-human primates, sloths, coati; zoonotic in humans. Arthropod vectors are sand flies in the genus Lutzomyia (Lainson et al. 1989).

Route of infection. Introduction of promastigotes via the bite of infected Lutzomyia sand fly (Steverding 2017; Torres-Guerrero et al. 2017).

Site in human host. Skin (Steverding 2017; Torres-Guerrero et al. 2017).

Genus Leptomonas Kent, 1880

Leptomonas seymouri (Wallace, 1877)

Geographic distribution. Worldwide (Kraeva et al. 2015).

Natural hosts. Insects. Zoonotic in humans (Ghosh et al. 2012; Kraeva et al. 2015; Thakur et al. 2020).

Route of infection. Presumed introduction of promastigotes via the bite of infected Phlebotomus sand flies (Ghosh et al. 2012; Kraeva et al. 2015; Thakur et al. 2020).

Site in human host. Skin, spleen, bone marrow (Ghosh et al. 2012; Kraeva et al. 2015; Thakur et al. 2020)

Notes. Human cases of L. seymouri to date have been found in Southeast Asia associated with co-infection with Leishmania donovani, suggesting incidental human infection after the bite of an infected sand fly vector.

Genus Trypanosoma Gruby, 1843

Subgenus Herpetosoma Doflein, 1901

Trypanosoma (H.) lewisi Laveran & Mesnil, 1901

Geographic distribution. Cosmopolitan (Desquesnes et al. 2002).

Natural hosts. Mammalian hosts are rats (Rattus spp.); zoonotic in humans. Arthropod vectors are rat fleas Nosophyllus fasciatus and Xenopsylla cheopis (Desquesnes et al. 2002).

Route of infection. Ingestion of infected fleas or their feces (Desquesnes et al. 2002).

Site in human host. Blood (Verma et al. 2011; de Sousa 2014).

Trypanosoma (H.) rangeli Tejera, 1920

Trypanosoma saimirii Rodhain, 1941

Geographic distribution. South America (Guhl and Vallejo 2003).

Natural hosts. Mammalian hosts include coati, sloths, tamandua, and opossums; zoonotic in humans. Arthropod vectors are triatomine bugs, most-notably members of the genus Rhodnius (Miles et al. 1983; Guhl and Vallejo 2003; Ferreira L de et al. 2015).

Route of infection. Introduction of trypomastigotes via the bite of infected triatomine bug (Guhl and Vallejo 2003; Ferreira L de et al. 2015).

Site in human host. Blood (Guhl and Vallejo 2003; Ferreira L de et al. 2015).

Subgenus Schizotrypanum Chagas, 1909

Trypanosoma (S.) cruzi Chagas, 1909

Geographic distribution. Southern United States, Central and South America (Bern et al. 2011; Kirchhoff 2011; Conners et al. 2016).

Natural hosts. Mammalian hosts include humans and many domestic and wild mammals. Arthropod vectors are triatomine bugs, most-notably members of the genera Triatoma, Panstrongylus, and Rhodnius (Kirchhoff 2011).

Route of infection. Introduction of metacyclic trypomastigotes in the feces of infected triatomine bug when rubbed into wounds or mucus membranes; ingestion of food contaminated with bugs or their feces; transplacentally from mother to fetus; via blood transfusion and organ transplantation (Coura 2015; Conners et al. 2016; Lidani et al. 2019).

Site in human host. Blood (acute infection, reactivation); heart muscle, esophagus, large intestine, peripheral nervous system, CNS, other organs (chronic infection) (Coura 2015; Conners et al. 2016; Lidani et al. 2019).

Subgenus Trypanozoon Lühe, 1906

Trypanosoma (T.) brucei gambiense (Dutton, 1902)

Geographic distribution. West-central Africa; hot spots of endemicity include Angola, Democratic Republic of Congo, South Sudan, Central African Republic, Uganda (Brun et al. 2010; Franco et al. 2014).

Natural hosts. Mammalian hosts include humans, non-human primates, and ungulates. Arthropod vectors are tsetse flies in the genus Glossina (Brun et al. 2010; Franco et al. 2014).

Route of infection. Introduction of trypomastigotes via the bite of infected Glossina tsetse fly (Brun et al. 2010).

Site in human host. Blood, lymphatics, CNS (Brun et al. 2010).

Trypanosoma (T.) brucei rhodesiense (Stephen & Fantham, 1910)

Geographic distribution. East and southeast Africa; hot spots of endemicity include Malawi, Zambia, Tanzania, Botswana, Kenya (Brun et al. 2010; Franco et al. 2014).

Natural hosts. Mammalian hosts include livestock and wild ungulates; zoonotic in humans. Arthropod vectors are tsetse flies in the genus Glossina (Brun et al. 2010; Franco et al. 2014).

Route of infection. Introduction of trypomastigotes via the bite of infected Glossina tsetse fly (Brun et al. 2010).

Site in human host. Blood, lymphatics, CNS (Brun et al. 2010).

Trypanosoma (T.) evansi Balbiani, 1888

Geographic distribution. Equatorial regions of Africa, Asia, Latin America (Van Vinh Chau et al. 2016).

Natural hosts. Mammalian hosts include horses, camels, bovids; zoonotic in humans. Arthropod vectors are biting flies in the genera Stomoxys and Tabanus (Van Vinh Chau et al. 2016).

Route of infection. Introduction of trypomastigotes via the bite of infected flies; possibly direct contact with blood/wounds of infected animals (Joshi et al. 2005; Powar et al. 2006; Van Vinh Chau et al. 2016).

Site in human host. Blood (Joshi et al. 2005; Powar et al. 2006; Van Vinh Chau et al. 2016).

Opisthokonta Cavalier-Smith, 1987, emend. Adl et al., 2005

Holozoa Lang et al., 2002

●● Metazoa Haeckel, 1874, emend. Adl et al. 2005

●●● Protostomia Grobben, 1908

●●●● Spiralia Edgecombe et al., 2011

●●●●● Acanthocephala Koelreuther, 1771

●●●●●● Oligacanthorhynchida Petrotschenko, 1956

●●●●●●● Oligacanthorhynchidae Southwell & Macfie, 1925

Genus Macracanthorhynchus Travassos, 1917

Macracanthorhynchus hirudinaceus (Pallas, 1781)

Taenia haeruca Pallas, 1776

Echinorhynchus gigas Bloch, 1782

Geographic distribution. Worldwide (Mathison et al. 2016).

Natural hosts. Intermediate hosts are insects, primarily scarabaeoid beetles. Definitive hosts are pigs; dogs and other mammals can serve as reservoir hosts. Zoonotic in humans (Mathison et al. 2016).

Route of infection. Ingestion of cystacanths in infected insect intermediate host (Mathison et al. 2016).

Site in human host. Small intestine (Mathison et al. 2016).

Macracanthorhynchus ingens (von Linstow, 1879)

Geographic distribution. Eastern North America (Elkins and Nickol 1983; Richardson et al. 2017).

Natural hosts. Intermediate hosts are millipedes. Definitive hosts are raccoons (Procyon lotor) and American black bear (Ursus americanus); many other mammals, especially carnivores, can serve as definitive hosts. Snakes and other animals may serve as paratenic hosts. Zoonotic in humans (Elkins and Nickol 1983; Richardson et al. 2017).

Route of infection. Ingestion of cystacanths in infected arthropod intermediate host or paratenic hosts (Mathison et al. 2016; Chancey et al. 2021).

Site in human host. Small intestine (Mathison et al. 2016; Chancey et al. 2021).

●●●●●● Moniliformida Schmidt, 1972

●●●●●●● Moniliformidae Van Cleave, 1924

Genus Moniliformis Travassos, 1915

Moniliformis moniliformis (Bremser, 1811)

Echinorhynchus grassi Railliet, 1893

Echinorhynchus canis Porta, 1914

Echinorhynchus belgicus Railliet, 1918

Moniliformis moniliformis siciliensis Meyer, 1932

Moniliformis moniliformis agypticus Meyer, 1932

Moniliformis dubius Meyer, 1932

Geographic distribution. Worldwide (Mathison et al. 2016).

Natural hosts. Intermediate hosts are insects, primarily beetles and cockroaches. Definitive hosts are primarily rodents and carnivores. Zoonotic in humans (Mathison et al. 2016).

Route of infection. Ingestion of cystacanths in infected insect intermediate host (Mathison et al. 2016).

Site in human host. Small intestine (Mathison et al. 2016).

●●●●●● Echinorhynchida Petrotschenko, 1956

●●●●●●● Echinorhynchidae Cobbold, 1876

Genus Acanthocephalus Koelreuther, 1771

Acanthocephalus rauschi (Schmidt, 1969)

Geographic distribution. Alaska (Schmidt 1969).

Natural hosts. Alaskan grayling (Thymallus arcticus). Otters can serve as paratenic hosts. Zoonotic in humans (Schmidt 1969).

Route of infection. Unknown; presumed ingestion of cystacanths in infected intermediate host.

Site in human host. Peritoneum (Schmidt 1969, 1971).

Genus Pseudoacanthocephalus Petrotschenko, 1958

Pseudoacanthocephalus bufonis (Shipley, 1903)

Acanthocephalus sinensis Van Cleave, 1937

Geographic distribution. Southeast Asia, Hawaii (Barton and Pichelin 1999; Bush et al. 2009).

Natural hosts. Toads. Zoonotic in humans (Bush et al. 2009).

Route of infection. Unknown; presumed ingestion of cystacanths in infected intermediate host.

Site in human host. Small intestine (Schmidt 1971).

●●●●●● Polymorphida Petrotschenko, 1956

●●●●●●● Polymorphidae Meyer, 1931

Genus Bolbosoma Porta, 1908

Bolbosoma nipponicum Yamaguti, 1939

Geographic distribution. North Atlantic (Yamaguti 1963).

Natural hosts. Marine crustaceans serve as intermediate hosts. Fish and cephalopods may serve as paratenic hosts. Whales and seals serve as definitive hosts. Zoonotic in humans (Yamaguti 1963).

Route of infection. Unknown; presumed ingestion of cystacanths in infected fish paratenic hosts.

Site in human host. Small intestine (Yamamoto et al. 2018).

Bolbosoma sp. cf. capitatum (von Linstow, 1880)

Geographic distribution. Worldwide (Amin and Margolis 1998).

Natural hosts. Marine crustaceans serve as intermediate hosts. Whales serve as definitive hosts. Zoonotic in humans (Amin and Margolis 1998).

Route of infection. Unknown; presumed ingestion of cystacanths in infected fish paratenic hosts.

Site in human host. Small intestine (Arizono et al. 2012).

Notes. The single case was reported from Japan as Bolbosoma cf. capitatim based on molecular and histological examination (Arizono et al. 2012).

Genus Corynosoma Lühe, 1904

Corynosoma strumosum (Rudolphi, 1802)

Geographic distribution. Worldwide (Aznar et al. 2006; Leidenberger et al. 2020).

Natural hosts. Intermediate hosts are marine amphipods. Several groups of fish may serve as paratenic hosts. Definitive hosts are seals, walrus, beluga whale. Zoonotic in humans (Aznar et al. 2006; Leidenberger et al. 2020; Nickol et al. 2002).

Route of infection. Ingestion of cystacanths in infected fish paratenic host (Schmidt 1971).

Site in human host. Small intestine (Schmidt 1971).

Corynosoma villosum Van Cleave, 1953

Geographic distribution. North Pacific (Moles 1982).

Natural hosts. Intermediate hosts are marine amphipods. Several groups of fish may serve as paratenic hosts. Definitive hosts are pinnipeds and whales. Zoonotic in humans (Moles 1982).

Route of infection. Ingestion of cystacanths in infected fish paratenic host (Fujita et al. 2016).

Site in human host. Small intestine (Fujita et al. 2016).

Corynosoma sp. cf. validum Van Cleave, 1953

Geographic distribution. North Pacific (Ionita et al. 2008).

Natural hosts. Intermediate hosts are marine amphipods. Several groups of fish may serve as paratenic hosts. Definitive host is the northern fur seal (Callorhinus ursinus), and other pinnipeds. Zoonotic in humans (Ionita et al. 2008).

Route of infection. Ingestion of cystacanths in infected fish paratenic host (Takahashi et al. 2016).

Site in human host. Small intestine (Takahashi et al. 2016).

Notes. The single case was reported from Japan as Corynosoma cf. validum based on DNA sequencing (Takahashi et al. 2016).

●●●●● Annelida Lamarck, 1802

●●●●●● Hirudinea Lamarck, 1818

●●●●●●● Rhynchobdellida Blanchard, 1894

●●●●●●●● Glossiphoniidae Vaillant, 1890

Genus Haementeria de Filippi, 1849

Haementeria acuecueyetzin Oceguera-Figueroa, 2008

Geographic distribution. Mexico (Oceguera-Figueroa 2008).

Natural hosts. Various vertebrates. Zoonotic on humans (Oceguera-Figueroa 2008; Charruau et al. 2020).

Route of infection. Exposure to fresh water (Oceguera-Figueroa 2008; Charruau et al. 2020).

Site in human host. Skin (Oceguera-Figueroa 2008).

Vectored pathogens. None.

Haementeria ghilianii de Filippi, 1849

Geographic distribution. Amazon South America (Sawyer et al. 1981).

Natural hosts. Various mammals. Zoonotic on humans (Sawyer et al. 1981; Farrar 2014).

Route of infection. Exposure to fresh water (Farrar 2014).

Site in human host. Skin (Farrar 2014).

Vectored pathogens. None.

Genus Parabdella Autrum, 1936

Parabdella quadrioculata (Moore, 1930)

Geographic distribution. East Asia (Moore 1930).

Natural hosts. Freshwater turtles and frogs. Zoonotic on humans (Moore 1930).

Route of infection. Exposure to fresh water (Yamauchi et al. 2013).

Site in human host. Skin (Yamauchi et al. 2013).

Vectored pathogens. None.

Genus Placobdella Blanchard, 1893

Placobdella costata (Müller, 1846)

Placobdella catenigera Moquin-Tandon, 1846

Geographic distribution. Mediterranean Region, Central Europe (Wilkialis 1973).

Natural hosts. Freshwater turtles. Zoonotic on humans (Wilkialis 1973).

Route of infection. Exposure to fresh water (Aloto 2018).

Site in human host. Skin (Aloto 2018).

Vectored pathogens. None.

●●●●●●● Hirudiniformes Caballero, 1952

●●●●●●●● Xerobdellidae Moore, 1946

Genus Diestecostoma Vaillant, 1890

Heterobdella Baird, 1869

Hygrobdella Caballero, 1940

Diestecostoma mexicana (Baird, 1869)

Geographic distribution. Central America (Oceguera-Figueroa and León-Règagnon 2014).

Natural hosts. Various mammals. Zoonotic on humans (Farrar 2014).

Route of infection. Environmental exposure (Farrar 2014).

Site in human host. Skin (Farrar 2014).

Vectored pathogens. None.

●●●●●●●● Haemadipsidae Blanchard, 1896

Genus Haemadipsa Tennent, 1859

Haemadipsa hainana Song, 1977

Geographic distribution. Southeast Asia (Tessler et al. 2018).

Natural hosts. Various mammals and birds. Zoonotic on humans (Tessler et al. 2018).

Route of infection. Environmental exposure (Tessler et al. 2018).

Site in human host. Skin (Tessler et al. 2018).

Vectored pathogens. None.

Haemadipsa interrupta Moore, 1935

Geographic distribution. Southeast Asia (Tessler et al. 2018).

Natural hosts. Various mammals and birds. Zoonotic on humans (Tessler et al. 2018).

Route of infection. Environmental exposure (Tessler et al. 2018).

Site in human host. Skin (Tessler et al. 2018).

Vectored pathogens. None.

Haemadipsa japonica Whitman, 1886

Geographic distribution. East Asia (Aizawa and Morishima 2018).

Natural hosts. Various mammals, birds, amphibians. Zoonotic on humans (Hanya et al. 2019).

Route of infection. Environmental exposure (Ji-Tuan 1997).

Site in human host. Skin, mucous membranes or the rectum and genital tract (Ji-Tuan 1997).

Vectored pathogens. None.

Haemadipsa picta Moore, 1929

Geographic distribution. Southeast Asia (Lai et al. 2011).

Natural hosts. Various large mammals, including humans (Lai et al. 2011).

Route of infection. Environmental exposure (Fogden and Proctor 1985; Lai et al. 2011).

Site in human host. Skin (Fogden and Proctor 1985; Lai et al. 2011).

Vectored pathogens. None.

Haemadipsa rjukjuana Oka, 1910

Geographic distribution. East Asia (Lai et al. 2011; Won et al. 2014).

Natural hosts. Various mammals, including humans, and birds (Lai et al. 2011).

Route of infection. Environmental exposure (Lai et al. 2011; Won et al. 2014).

Site in human host. Skin (Lai et al. 2011; Won et al. 2014).

Vectored pathogens. None

Haemadipsa sylvestris Blanchard, 1894

Geographic distribution. Southeast Asia (Farrar 2014).

Natural hosts. Various mammals. Zoonotic on humans (Farrar 2014).

Route of infection. Environmental exposure (Farrar 2014).

Site in human host. Skin (Farrar 2014).

Vectored pathogens. None.

Haemadipsa trimaculosa Ngamprasertwong et al., 2007

Geographic distribution. Southeast Asia (Ngamprasertwong et al. 2007; Tessler et al. 2018).

Natural hosts. Various mammals and birds. Zoonotic on humans (Ngamprasertwong et al. 2007).

Route of infection. Environmental exposure (Tessler et al. 2018).

Site in human host. Skin (Tessler et al. 2018).

Vectored pathogens. None

Haemadipsa zeylanica (Moquin-Tandon, 1826)

Geographic distribution. Japan, Southeast Asia (Fogden and Proctor 1985).

Natural hosts. Various amphibians and mammals. Zoonotic on humans (Fogden and Proctor 1985).

Route of infection. Environmental exposure (Fogden and Proctor 1985).

Site in human host. Skin (Fogden and Proctor 1985).

Vectored pathogens. None.

Genus Phytobdella Blanchard, 1894

Phytobdella catenifera Moore, 1942

Geographic distribution. Malaysia (Farrar 2014).

Natural hosts. Reptiles. Zoonotic on humans (Farrar 2014).

Route of infection. Environmental exposure (Farrar 2014).

Site in human host. Skin (Farrar 2014).

Vectored pathogens. None.

●●●●●●●● Hirudinidae Whitman, 1886

Genus Hirudo Linnaeus, 1758

Hirudo medicinalis Linnaeus, 1758

Geographic distribution. Europe, Asia (Kutschera and Elliott 2014).

Natural hosts. Immature stages usually on amphibians. Adults on mammals. Zoonotic on humans (Kutschera and Elliott 2014).

Route of infection. Exposure to fresh water (Kutschera and Elliott 2014).

Site in human host. Skin (Kutschera and Elliott 2014).

Vectored pathogens. Aeromonas spp. (Graf 1999).

Hirudo nipponia Whitman, 1886

Geographic distribution. Russia, Japan, Southeast Asia (Yang 1996).

Natural hosts. Immature stages usually on amphibians. Adults on mammals. Zoonotic on humans (Yang 1996).

Route of infection. Exposure to fresh water (Oda et al. 1984).

Site in human host. Skin, Eye (Oda et al. 1984).

Vectored pathogens. None.

Hirudo orientalis Utevsky & Trontelj, 2005

Geographic distribution. Central Asia, Eastern Europe (Utevsky and Trontelj 2005).

Natural hosts. Immature stages usually on amphibians. Adults on mammals. Zoonotic on humans (Utevsky and Trontelj 2005).

Route of infection. Exposure to fresh water (Utevsky and Trontelj 2005).

Site in human host. Skin, Eye (Utevsky and Trontelj 2005).

Vectored pathogens. Aeromonas spp. (Laufer et al. 2008).

Hirudo troctina Johnson, 1816

Geographic distribution. North Africa, Iberian Peninsula (Marrone and Canale 2019).

Natural hosts. Immature stages usually on amphibians. Adults on mammals. Zoonotic on humans (Trontelj and Utevsky 2005).

Route of infection. Exposure to fresh water (Trontelj and Utevsky 2005).

Site in human host. Skin, Eye (Trontelj and Utevsky 2005).

Vectored pathogens. None.

Hirudo verbena Carena, 1820

Geographic distribution. Mediterranean Europe (Marrone and Canale 2019).

Natural hosts. Immature stages usually on amphibians. Adults on mammals. Zoonotic on humans (Kutschera and Elliott 2014).

Route of infection. Exposure to fresh water (Kutschera and Elliott 2014).

Site in human host. Skin (Kutschera and Elliott 2014).

Vectored pathogens. Aeromonas spp. (Laufer et al. 2008).

Genus Hirudinaria Whitman, 1886

Hirudinaria manillensis (Lesson, 1842)

Hirudo multistriata Schmarda, 1861

Hirudo luzoniae Kinberg, 1866

Hirudo maculosa Grube, 1868

Hirudo maculata Baird, 1869

Limnatis granulosa Blanchard, 1893

Hirudo boyntoni Wharton, 1913

Geographic distribution. Southeast Asia (Jeratthitikul et al. 2020).

Natural hosts. Mammals, including buffalo, cattle. Zoonotic in humans (Jeratthitikul et al. 2020).

Route of infection. Exposure to fresh water (Hii et al. 1978).

Site in human host. Upper respiratory tract (Hii et al. 1978).

Vectored pathogens. None

Genus Limnatis Moquin-Tandon, 1827

Limnatis nilotica (Savigny, 1822)

Geographic distribution. Southern Europe, North Africa, Middle East (Arfuso et al. 2019).

Natural hosts. Mammals, including sheep, cattle, dogs, and donkeys. Zoonotic on humans (Arfuso et al. 2019).

Route of infection. Exposure to fresh water

Site in human host. Upper respiratory tract (Almallah 1968; Ağin et al. 2008).

Vectored pathogens. None.

Genus Poecilobdella Blanchard, 1893

Poecilobdella granulosa (Savigny, 1822)

Geographic distribution. India, Sri Lanka, Southeast Asia (Nesemann and Sharma 2001).

Natural hosts. Amphibians, Mammals. Zoonotic in humans (Nesemann and Sharma 2001).

Route of infection. Exposure to fresh water (Zainuddin et al. 2016).

Site in human host. Skin, upper respiratory tract (Zainuddin et al. 2016).

Vectored pathogens. None.

Poecilobdella viridis Moore in Harding & Moore, 1927

Geographic distribution. India, Sri Lanka (Kulkarni et al. 1977).

Natural hosts. Amphibians, Mammals. Zoonotic in humans (Kulkarni et al. 1977).

Route of infection. Exposure to fresh water (Zainuddin et al. 2016).

Site in human host. Upper respiratory tract (Zainuddin et al. 2016).

Vectored pathogens. None.

●●●●●●●● Macrobdellidae Richardson, 1969

Genus Macrobdella Verrill, 1872

Macrobdella decora (Say, 1824)

Geographic distribution. Eastern North America, Mexico (Phillips et al. 2016, 2019).

Natural hosts. Various vertebrate animals. Zoonotic on humans (Phillips et al. 2016, 2019).

Route of infection. Exposure to fresh water (Phillips et al. 2016, 2019).

Site in human host. Skin (Phillips et al. 2016, 2019).

Vectored pathogens. None.

Macrobdella diplotertia Meyer, 1975

Geographic distribution. East-central United States (Phillips et al. 2016, 2019).

Natural hosts. Various vertebrate animals. Zoonotic on humans (Phillips et al. 2016, 2019).

Route of infection. Exposure to fresh water (Phillips et al. 2016, 2019).

Site in human host. Skin (Phillips et al. 2016, 2019).

Vectored pathogens. None.

Macrobdella ditetra Moore, 1953

Geographic distribution. Southeastern United States (Phillips et al. 2016, 2019).

Natural hosts. Various vertebrate animals. Zoonotic on humans(Phillips et al. 2016, 2019).

Route of infection. Exposure to fresh water (Phillips et al. 2016, 2019).

Site in human host. Skin (Phillips et al. 2016, 2019).

Vectored pathogens. None.

Macrobdella mimicus Phillips, 2019

Geographic distribution. Northeastern United States (Phillips et al. 2019).

Natural hosts. Various vertebrate animals. Zoonotic on humans (Phillips et al. 2019).

Route of infection. Exposure to fresh water (Phillips et al. 2019).

Site in human host. Skin (Phillips et al. 2019).

Vectored pathogens. None.

Macrobdella sestertia Whitman, 1886

Geographic distribution. Northeastern United States (Phillips et al. 2016, 2019).

Natural hosts. Various vertebrate animals. Zoonotic on humans (Phillips et al. 2016, 2019).

Route of infection. Exposure to fresh water (Phillips et al. 2016, 2019).

Site in human host. Skin (Phillips et al. 2016, 2019).

Vectored pathogens. None.

●●●●●●●● Praeobdellidae Sawyer, 1986

Genus Dinobdella Moore in Harding & Moore, 1927

Dinobdella ferox (Blanchard, 1896)

Geographic distribution. India, Southeast Asia (Lai 2019).

Natural hosts. Various mammals. Zoonotic on humans (Lai 2019).

Route of infection. Exposure to fresh water (Makiya et al. 1988).

Site in human host. Nasal mucosa (Makiya et al. 1988).

Vectored pathogens. None.

Genus Myxobdella Oka, 1917

Myxobdella africana Moore, 1939

Geographic distribution. Sub-Saharan Africa (Cundall et al. 1986; Estambale et al. 1992).

Natural hosts. Mammals, including dogs. Zoonotic in humans (Cundall et al. 1986; Estambale et al. 1992).

Route of infection. Exposure to fresh water (Cundall et al. 1986; Estambale et al. 1992).

Site in human host. Upper respiratory tract (Cundall et al. 1986; Estambale et al. 1992).

Vectored pathogens. None.

Genus Tyrannobdella Philipps et al., 2010

Tyrannobdella rex Phillips et al., 2010

Geographic distribution. Amazon South America (Phillips et al. 2010).

Natural hosts. Unknown; presumed zoonotic on humans (Phillips et al. 2010).

Route of infection. Exposure to fresh water (Phillips et al. 2010).

Site in human host. Nasopharynx (Phillips et al. 2010).

Vectored pathogens. None.

●●●●● Cestoda Rudolphi, 1809

●●●●●● Eucestoda Southwell, 1930

●●●●●●● Diphyllobothriidea Kuchta et al., 2008

●●●●●●●● Diphyllobothriidae Lühe, 1910

Genus Adenocephalus Nybelin, 1931

Adenocephalus pacificus Nybelin, 1931

Adenocephalus septentrionalis Nybelin, 1931

Diphyllobothrium arctocephali Drummond, 1937

Diphyllobothrium krotovi Delyamure, 1955

Dibothriocephalus atlanticum Delyamure & Parukhin, 1968

Geographic distribution. Coastal Pacific waters and southern Africa (Hernandez-Orts et al. 2015; Kuchta et al. 2015).

Natural hosts. The first arthropod intermediate host is unknown, but presumed to be marine copepods. The second intermediate hosts are various marine fish. Definitive hosts are eared seals and sea lions; dogs and jackals can serve as reservoir hosts. Zoonotic in humans (Hernandez-Orts et al. 2015; Kuchta et al. 2015).

Route of infection. Ingestion of plerocercoids in infected fish (Kuchta et al. 2015).

Site in human host. Small intestine (Kuchta et al. 2015).

Genus Dibothriocephalus Lühe, 1899

Dibothriocephalus dalliae (Rausch, 1956)

Geographic distribution. Northern Pacific (Alaska and northeastern Siberia) (Scholz and Kuchta 2016).

Natural hosts. First intermediate hosts are freshwater copepods. Second intermediate hosts are freshwater fish, primarily Alaska blackfish (Dallia pectoralis). Definitive hosts are Arctic fox, with domestic dogs as reservoir hosts. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Dibothriocephalus dendriticus (Nitzsch, 1824)

Dibothriocephalus fissiceps Creplin, 1829

Dibothriocephalus cordiceps Leidy, 1872

Dibothriocephalus exile Linton, 1892

Sparganum sebago Ward, 1910

Dibothriocephalus minor Cholodkovsky, 1916

Diphyllobothrium canadense Cooper, 1921

Diphyllobothrium strictum Talysin, 1932

Diphyllobothrium obdoriense Piotnikoff, 1933

Diphyllobothrium laruei Vergeer, 1934

Diphyllobothrium nenzi Petrov, 1938

Diphyllobothrium oblongatum Thomas, 1946

Diphyllobothrium medium Fahmy, 1954

Diphyllobothrium microcordiceps Szidat & Soria, 1957

Diphyllobothrium norvegicum Vik, 1957

Geographic distribution. Holarctic (Scholz and Kuchta 2016).

Natural hosts. The first intermediate hosts are freshwater copepods. The second intermediate and paratenic hosts are many different freshwater fish. Definitive hosts are fish-eating birds, primarily gulls, and mammals, including wild and domestic canids, bears, and otters. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Kuchta et al. 2013).

Site in human host. Small intestine (Kuchta et al. 2013).

Dibothriocephalus hians Diesing, 1850

Geographic distribution. Mediterranean and Circumboreal (Scholz and Kuchta 2016).

Natural hosts. The first intermediate hosts are presumed to be marine copepods. The second intermediate hosts are unknown, but presumed to be marine fish. Definitive hosts are seals. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Dibothriocephalus latus (Linnaeus, 1758)

Diphyllobothrium americanum Hall & Wigdor, 1918

Diphyllobothrium tungussicum Podyapolskaya & Gnedina, 1932

Diphyllobothrium skrjabini Plotnikoff, 1933

Geographic distribution. Holarctic, South America (Scholz and Kuchta 2016).

Natural hosts. The first intermediate hosts are freshwater copepods. The second intermediate and paratenic hosts are freshwater fish, including perch, pike, burbot, walleye, and pikeperch. Definitive hosts are fish-eating carnivores, including wild and domestic dogs and cats, bears, and mustelids. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz et al. 2009).

Site in human host. Small intestine (Scholz et al. 2009).

Dibothriocephalus nihonkaiensis (Yamane et al., 1886)

Diphyllobothrium giljacicum Rutkevich, 1937

Diphyllobothrium klebanovskii Muratov & Posokov, 1988

Geographic distribution. Northern Pacific (Scholz and Kuchta 2016; Ikuno et al. 2018).

Natural hosts. First intermediate hosts are marine copepods. Second intermediate hosts are salmonid fish. Definitive hosts are bears, wild canids, and mink. Zoonotic in humans.

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Dibothriocephalus ursi (Rausch, 1954)

Diphyllobothrium gonodo Yamaguti, 1942

Geographic distribution. Northern North America (Scholz and Kuchta 2016).

Natural hosts. First intermediate hosts are marine copepods. Second intermediate hosts are salmonid fish, primarily sockeye salmon (Oncorhynchus nerka). Definitive hosts are bears. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Genus Diphyllobothrium Cobbold, 1858

Diphyllobothrium balaenopterae (Lönnberg, 1892)

Krabbea grandis Blanchard, 1894

Diplogonoporus fukuokaensis Kamo & Miyazaki, 1970

Geographic distribution. Worldwide (Scholz and Kuchta 2016).

Natural hosts. First intermediate hosts are marine copepods. Second intermediate hosts are marine fish, including Japanese anchovy, Japanese sardine, and skipjack tuna. Definitive hosts are baleen whales. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Diphyllobothrium stemmacephalum Cobbold, 1858

Diphyllobothrium ponticum Delyamure, 1971

Diphyllobothrium yonagoense Yamane et al., 1981

Geographic distribution. Northern Hemisphere (Scholz and Kuchta 2016).

Natural hosts. First intermediate hosts are presumed to be marine copepods. Second intermediate hosts are unknown, but presumed to be marine fish. Definitive hosts are dolphins and porpoises. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Diphyllobothrium , incertae sedis:

Diphyllobothrium cordatum (Leuckart, 1863)

Geographic distribution. Circumpolar (Scholz and Kuchta 2016).

Natural hosts. First intermediate hosts are presumed to be marine copepods. Second intermediate hosts are unknown, but presumed to be marine fish. Definitive hosts are seals and walrus. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Diphyllobothrium lanceolatum (Krabbe, 1865)

Geographic distribution. Circumpolar (Scholz and Kuchta 2016).

Natural hosts. First intermediate hosts are marine copepods. Second intermediate hosts are marine fish, including sardine cisco (Coregonus sardinella). Definitive hosts are seals. Zoonotic in humans (Scholz and Kuchta 2016).

Route of infection. Ingestion of plerocercoids in infected fish (Scholz and Kuchta 2016).

Site in human host. Small intestine (Scholz and Kuchta 2016).

Genus Spirometra Faust et al., 1929

Spirometra decepiens (Diesing, 1850)

Geographic distribution. North and South America, Southeast Asia (Jeon et al. 2015; Jeon et al. 2018b).

Natural hosts. First intermediate hosts are believed to be freshwater copepods. Second intermediate hosts are believed to be freshwater fish and/or amphibians. Definitive hosts are wild and domestic cats; dogs may serve as reservoir hosts. Zoonotic in humans as dead-end hosts that harbor plerocercoid larvae (Jeon et al. 2015; Jeon et al. 2018b).

Route of infection. Ingestion of plerocercoids in infected paratenic or intermediate host; ingestion of water containing copepods infected with procercoids (Jeon et al. 2015; Jeon et al. 2018b).

Site in human host. Skin and soft tissues, pleural and peritoneal cavities, abdominal viscera, eye, CNS (Jeon et al. 2015; Jeon et al. 2018b).

Spirometra erinaceieuropaei (Rudolphi, 1819)

Geographic distribution. Europe, Asia, and Australia (Tang et al. 2017; Kuchta et al. 2021).

Natural hosts. First intermediate hosts are freshwater copepods. Second intermediate hosts are amphibians, reptiles and mammals. Definitive hosts are believed to be wild and domestic canids and felids. Zoonotic in humans as dead-end hosts that harbor plerocercoid larvae (Tang et al. 2017; Kuchta et al. 2021).

Route of infection. Ingestion of plerocercoids in infected paratenic or intermediate host; ingestion of water containing copepods infected with procercoids (Lee et al. 1984; Tang et al. 2017).

Site in human host. Skin and soft tissues, pleural and peritoneal cavities, abdominal viscera, eye, CNS as plerocercoid larvae (spargana); rarely as adults in small intestine (Lee et al. 1984; Tang et al. 2017).

Spirometra mansoni (Joyeux & Houdemer, 1928)

Geographic distribution. Southeast Asia (Hong et al. 2016).

Natural hosts. First intermediate hosts are freshwater copepods. Second intermediate hosts are amphibians, while reptiles, birds, and pigs may serve as paratenic hosts. Definitive hosts are felids and canids. Zoonotic in humans as dead-end hosts that harbor plerocercoid larvae (Hong et al. 2016).

Route of infection. Ingestion of plerocercoids in infected paratenic or intermediate host; ingestion of water containing copepods infected with procercoids (Galan-Puchades 2019).

Site in human host. Skin and soft tissues, pleural and peritoneal cavities, abdominal viscera, eye, CNS (Galan-Puchades 2019).

Spirometra mansonoides (Mueller, 1935)

Geographic distribution. North America (McHale et al. 2020).

Natural hosts. First intermediate hosts are freshwater copepods. Second intermediate hosts are amphibians, reptiles, birds, small mammals. Definitive hosts are felids and canids. Zoonotic in humans as dead-end hosts that harbor plerocercoid larvae (McHale et al. 2020).

Route of infection. Ingestion of plerocercoids in infected paratenic or intermediate host; ingestion of water containing copepods infected with procercoids (Landero et al. 1991).

Site in human host. Skin and soft tissues, pleural and peritoneal cavities, abdominal viscera, eye, CNS (Landero et al. 1991).

Spirometra ranarum (Gastaldi, 1854)

Geographic distribution. Africa, Southeast Asia (Jeon et al. 2018a; Saksirisampant et al. 2020).

Natural hosts. First intermediate hosts are freshwater copepods. Second intermediate hosts are amphibians and reptiles. Definitive hosts are wild and domestic felids and canids. Zoonotic in humans as dead-end hosts that harbor plerocercoid larvae (Jeon et al. 2018a; Saksirisampant et al. 2020).

Route of infection. Ingestion of infected intermediate or paratenic host (Saksirisampant et al. 2020).

Site in human host. Skin and soft tissues, pleural and peritoneal cavities, abdominal viscera, eye, CNS (Saksirisampant et al. 2020).

Spirometra spp.

Geographic distribution. East Africa (Eberhard et al. 2015).

Natural hosts. Unknown (Eberhard et al. 2015).

Route of infection. Either ingestion of plerocercoids in undercooked intermediate or paratenic hosts, or water containing copepods infected with procercoids (Eberhard et al. 2015).

Site in human host. Skin and soft tissues (Eberhard et al. 2015).

Notes. Several infections with Spirometra sp. have been confirmed in South Sudan and sporadically in other East African countries. Molecular data have confirmed distinctiveness from other known zoonotic Spirometra spp., but no specific identification has been determined (Eberhard et al. 2015).

Diphyllobothriidae, incertae sedis:

Sparganum proliferum (Ilima, 1905)

Geographic distribution. Undefined (Mueller and Strano 1974).

Natural hosts. Unknown, currently known only from humans in which it is believed to be zoonotic (Mueller and Strano 1974).

Route of infection. Unknown, but presumed to be ingestion of infected intermediate or paratenic host (Mueller and Strano 1974).

Site in human host. Skin and soft tissues, pleural and peritoneal cavities, abdominal viscera, eye, CNS (Mueller and Strano 1974).

Notes. The name Sparganum proliferum is the name given to an enigmatic parasite of unknown affinities. To date, it is only known from its larval form from humans.

●●●●●●● Cyclophyllidea van Beneden in Braun, 1990

●●●●●●●● Dipylidiidae Stiles, 1896

Genus Dipylidium Leuckart, 1863

Microtaenia Sedgwick in Claus & Sedwick, 1884

Dipylidium caninum (Linnaeus, 1758)

Geographic distribution. Worldwide (Sapp and Bradbury 2020).

Natural hosts. Intermediate hosts are insects, primarily fleas (Ctenocephalides, Pulex) and lice (Trichodectes). Definitive hosts are wild and domestic felids and canids. Zoonotic in humans (Sapp and Bradbury 2020).

Route of infection. Ingestion of cysticercoids in infected arthropod intermediate host (Cabello et al. 2011; Sapp and Bradbury 2020).

Site in human host. Small intestine (Cabello et al. 2011; Sapp and Bradbury 2020).

●●●●●●●● Hymenolepididae Ariola, 1899

Genus Hymenolepis Weinland, 1858

Hymenolepis diminuta (Rudolphi, 1819)

Taenia flavopunctata Weinland, 1858

Geographic distribution. Worldwide (Arai 1980).

Natural hosts. Intermediate hosts are insects, commonly granary beetles. Definitive hosts are rodents (primarily rats). Zoonotic in humans (Arai 1980).

Route of infection. Ingestion of cysticercoids infected insect intermediate host (Tiwari et al. 2014).

Site in human host. Small intestine (Tiwari et al. 2014).

Hymenolepis hibernia Montgomery et al., 1987

Geographic distribution. Europe, Asia (Sargison et al. 2018).

Natural hosts. Intermediate hosts are beetles. Definitive hosts are mice in the genus Apodemus. Zoonotic in humans (Sargison et al. 2018).

Route of infection. Presumed ingestion of cysticercoids in infected insect intermediate host (Nkouawa et al. 2016).

Site in human host. Small intestine (Nkouawa et al. 2016).

Genus Rodentolepis Spasskii, 1954

Rodentolepis microstoma (Dujardin, 1845)

Geographic distribution. Worldwide (Cunningham and Olson 2010).

Natural hosts. Intermediate hosts are insects, commonly granary beetles and fleas. Definitive hosts are fleas. Zoonotic in humans (Andreassen et al. 2004; Cunningham and Olson 2010).

Route of infection. Presumably, ingestion of cysticercoids in infected insect intermediate host (Macnish et al. 2003).

Site in human host. Small intestine (Macnish et al. 2003).

Notes. The few cases of H. microstoma in humans have been diagnosed by molecular detection in stool (Macnish et al. 2003).

Rodentolepis nana (Bilharz, 1851)

Hymenolepis fraterna Stiles, 1906

Geographic distribution. Worldwide (Sataeva et al. 2018).

Natural hosts. Intermediate hosts are insects, commonly granary beetles and fleas. Definitive hosts are rodents. Zoonotic in humans, although human-to-human transmission can occur (Sataeva et al. 2018).

Route of infection. Ingestion of cysticercoids in infected insect intermediate host; ingestion of eggs on fecally contaminated fomites (Thompson 2015; Sataeva et al. 2018).

Site in human host. Small intestine (Thompson 2015; Sataeva et al. 2018).

●●●●●●●● Taeniidae Ludwig, 1886

Genus Echinococcus Rudolphi, 1801

Echinococcus canadensis Webster & Cameron, 1961

Echinococcus granulosus borealis Williams & Sweatman, 1863

Echinococcus G6, camel-pig strain

Echinococcus G7, camel-pig strain

Echinococcus G8, American cervid strain

Echinococcus G10, Fennoscandian strain

Geographic distribution. North America, Europe, Middle East, China, east Africa (Romig et al. 2015; Hua et al. 2019).

Natural hosts. Intermediate hosts are camels, pigs, goats, and deer. Definitive hosts are wild and domestic canids. Zoonotic in humans as dead-end hosts harboring larval cysts (Romig et al. 2015; Hua et al. 2019).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with dog feces (Romig et al. 2015).

Site in human host. Disseminated infection, common sites of colonization are liver, lung, brain, bone (Romig et al. 2015).

Echinococcus equinus Willams & Sweatman, 1963

Echinococcus G4, horse strain

Geographic distribution. Europe, North Africa, Middle East (Romig et al. 2015).

Natural hosts. Intermediate hosts are horses. Definitive hosts are wild and domestic canids. Zoonotic in humans as dead-end hosts harboring larval cysts (Romig et al. 2015).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Romig et al. 2015; Kim et al. 2020).

Site in human host. Disseminated infection, common sites of colonization are liver, lung, brain, bone (Kim et al. 2020).

Echinococcus granulosus (Batsch, 1796)

Echinococcus minimus Cameron, 1926

Echinococcus longimanubrius Cameron, 1926

Echinococcus cameroni Ortlepp, 1934

Echinococcus lycaontis Ortlepp, 1934

Echinococcus intermedius Lopez-Neyra & Soler Planas, 1943

Echinococcus patagonicus Szidat, 1960

Echinococcus cepanzoi Szidat, 1971

Echinococcus G1, sheep-buffalo strain

Echinococcus G2, sheep-buffalo strain

Echinococcus G3, sheep-buffalo strain

Geographic distribution. Worldwide (Eckert and Deplazes 2004; Romig et al. 2015).

Natural hosts. Intermediate hosts are primarily sheep, goats, cattle, and buffalo. Definitive hosts are wild and domestic canids. Zoonotic in humans as dead-end hosts harboring larval cysts (Eckert and Deplazes 2004; Romig et al. 2015).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Eckert and Deplazes 2004; Romig et al. 2015).

Site in human host. Disseminated infection, common sites of colonization are liver, lung, brain, bone (Eckert and Deplazes 2004; Romig et al. 2015).

Echinococcus multilocularis (Leuckart, 1863)

Echinococcus sibiricensis Rausch & Schiller, 1964

Echinococcus russicensis Tang et al., 2007

Geographic distribution. Europe, Asia, North America (Eckert and Deplazes 2004; Conraths and Deplazes 2015).

Natural hosts. Intermediate hosts are rodents, primarily voles. Definitive hosts are wild canids, primarily red fox (Vulpes vulpes); raccoon dogs, domestic dogs, and domestic cats may serve as reservoir hosts. Zoonotic in humans as dead-end hosts harboring larval cysts (Conraths and Deplazes 2015; Eckert and Deplazes 2004).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Eckert and Deplazes 2004; Conraths and Deplazes 2015).

Site in human host. Liver, with dissemination to other organs, such as lung, heart, brain, bone (Eckert and Deplazes 2004; Conraths and Deplazes 2015).

Echinococcus oligarthra Diesing, 1863

Echinococcus cruzi Brumpt & Joyeux, 1924

Echinococcus pampeanus Szidat, 1967

Geographic distribution. South America (D’Alessandro and Rausch 2008).

Natural hosts. Intermediate hosts are rodents and marsupials. Definitive hosts are wild felids. Zoonotic in humans as dead-end hosts harboring larval cysts (D’Alessandro and Rausch 2008).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with felid feces (D’Alessandro and Rausch 2008).

Site in human host. Liver, peritoneal and pleural cavities, with dissemination to other organs (D’Alessandro and Rausch 2008).

Echinococcus ortleppi Lopez-Neyra & Soler Planas, 1943

Echinococcus G5, cattle strain

Geographic distribution. Africa, Europe, India, South America (Romig et al. 2015).

Natural hosts. Intermediate hosts are primarily bovids. Definitive hosts are wild and domestic canids. Zoonotic in humans as dead-end hosts harboring larval cysts (Romig et al. 2015).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Romig et al. 2015).

Site in human host. Disseminated infection, common sites of colonization are liver, lung, brain, bone (Romig et al. 2015).

Echinococcus vogeli Rausch & Berstein, 1972

Geographic distribution. South America (D’Alessandro and Rausch 2008).

Natural hosts. Intermediate hosts are rodents, primarily paca (Cuniculus paca). Definitive hosts are bush dogs (Speothos venaticus). Zoonotic in humans as dead-end hosts harboring larval cysts (D’Alessandro and Rausch 2008).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with bush dog feces (D’Alessandro and Rausch 2008).

Site in human host. Liver, peritoneal and pleural cavities, with dissemination to other organs (D’Alessandro and Rausch 2008).

Genus Hydatigera Lamarck, 1816

Hydatigera taeniaeformis (Batsch, 1786)

Cysticercus fasciolaris Rudolphi, 1808

Geographic distribution. Worldwide (Nakao et al. 2013; Guo 2020).

Natural hosts. Intermediate hosts are primarily rodents and lagomorphs. Definitive hosts are felids. Zoonotic in humans (Nakao et al. 2013; Guo 2020).

Route of infection. Unknown

Site in human host. Small intestine, liver (Stĕrba and Barus 1976; Guo 2020).

Genus Taenia Linnaeus, 1758

Taenia brauni Setti, 1897

Geographic distribution. Africa (Deplazes et al. 2019).

Natural hosts. Intermediate hosts are rodents and non-human primates. Definitive hosts are canids and genets. Zoonotic in humans as dead-end hosts harboring larval cysts (Deplazes et al. 2019).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Lescano and Zunt 2013).

Site in human host. Skin and soft tissues, eyes (Vanderick et al. 1964; Lescano and Zunt 2013; Deplazes et al. 2019).

Notes. Taenia brauni is often considered a subspecies or synonym of T. serialis.

Taenia crassiceps (Zeder, 1800)

Taenia hyperborea von Linstow, 1905

Geographic distribution. Northern Hemisphere (Ntoukas et al. 2013).

Natural hosts. Intermediate hosts are rodents. Definitive hosts are canids, primarily foxes Zoonotic in humans as dead-end hosts harboring larval cysts (Freeman 2011; Ntoukas et al. 2013).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Ntoukas et al. 2013; Tappe et al. 2016a).

Site in human host. Skin and soft tissues, eyes, CNS (Ntoukas et al. 2013; Tappe et al. 2016a).

Taenia glomeratus (Railliett & Henry, 1915)

Geographic distribution. Africa (Deplazes et al. 2019).

Natural hosts. Intermediate hosts are rodents. Definitive hosts are canids and genets. Zoonotic in humans as dead-end hosts harboring larval cysts (Lescano and Zunt 2013; Deplazes et al. 2019).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Lescano and Zunt 2013; Deplazes et al. 2019).

Site in human host. Eyes (Lescano and Zunt 2013; Deplazes et al. 2019).

Notes. Taenia glomeratus is often considered a subspecies or synonym of T. serialis.

Taenia martis (Zeder, 1803)

Geographic distribution. North America, Europe (Brunet et al. 2015).

Natural hosts. Intermediate hosts include rodents. Definitive hosts are mustelids and foxes. Zoonotic in humans has a dead-end host harboring larval cysts (Eberwein et al. 2013; Brunet et al. 2015; Deplazes et al. 2019).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with feces of definitive host (Brunet et al. 2015; Deplazes et al. 2019).

Site in human host. Skin and soft tissues, CNS, eyes (Eberwein et al. 2013; Brunet et al. 2015; Deplazes et al. 2019).

Taenia multiceps Leske, 1790

Geographic distribution. Worldwide (Varcasia et al. 2015).

Natural hosts. Intermediate hosts are ungulates, primarily sheep. Definitive hosts are canids, primarily foxes. Zoonotic in humans as dead-end hosts harboring larval cysts (Varcasia et al. 2015; Deplazes et al. 2019).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Deplazes et al. 2019).

Site in human host. Skin and soft tissues, CNS (Deplazes et al. 2019).

Taenia saginata Goeze, 1782

Taenia confusa Ward, 1896

Taenia africana von Linstow, 1900

Taenia hominis von Linstow, 1904

Geographic distribution. Worldwide (Hoberg 2002; Braae et al. 2018).

Natural hosts. Intermediate hosts are cattle. Definitive hosts are humans (Braae et al. 2018; Hoberg 2002).

Route of infection. Ingestion of cysticercoids in infected cattle (Braae et al. 2018).

Site in human host. Small intestine (Braae et al. 2018).

Taenia serialis Gervais, 1847

Multiceps radians Joyeux et al., 1922

Geographic distribution. Worldwide; highest prevalence in Africa (Schneider-Crease et al. 2017).

Natural hosts. Intermediate hosts include rabbits, rodents, cattle, sheep, goats. Definitive hosts are wild and domestic canids. Zoonotic in humans as dead-end hosts harboring larval cysts (Schneider-Crease et al. 2017).

Route of infection. Ingestion of eggs in food, water, fomites contaminated with canid feces (Tappe et al. 2016a).

Site in human host. CNS (Tappe et al. 2016a).

Taenia solium Linnaeus, 1758

Cysticercus cellulosae Gmelin, 1790

Geographic distribution. Worldwide (Garcia et al. 2003; Nakao et al. 2002; Coral-Almeida et al. 2015).

Natural hosts. Intermediate hosts are pigs. Definitive hosts are humans, although in cases of cysticercosis humans function as dead-end intermediate hosts (Garcia et al. 2003; Coral-Almeida et al. 2015).

Route of infection. Ingestion of cysticercoids in infected pigs (taeniasis); ingestion of eggs in food, water, fomites contaminated with human feces (cysticercosis) (Garcia et al. 2003).

Site in human host. Small intestine (taeniasis); disseminated infection with predilection for CNS (cysticercosis) (Garcia et al. 2003).

Taenia suihominis Mathison et al., 2021

Taenia asiatica Eom & Rim, 1993

Taenia saginata asiatica Eom & Rim, 1993

Taenia asiaticus Eom et al., 2020

Geographic distribution. East Asia (Ale et al. 2014).

Natural hosts. Intermediate hosts are pigs. Definitive hosts are humans (Eom and Rim 1993; Ale et al. 2014).

Route of infection. Ingestion of cysticerci in infected pigs (Ale et al. 2014; Eom and Rim 1993).

Site in human host. Small intestine (Eom and Rim 1993; Ale et al. 2014).

Genus Versteria Nakao et al., 2013

Geographic distribution. Europe, Central Asia, North America (Nakao et al. 2013; Deplazes et al. 2019).

Natural hosts. Intermediate hosts are rodents; non-human primates can be incidental hosts. Definitive hosts are mustelids. Zoonotic in humans (Nakao et al. 2013; Deplazes et al. 2019).

Route of infection. Presumably by the ingestion of eggs in food, water, fomites contaminated with feces of definitive host (Deplazes et al. 2019).

Site in human hose. Various organs, disseminated infection (Barkati et al. 2018; Lehman et al. 2019).

Notes. Human and primate Versteria infections have not been identified to species level but bear close genetic resemblance to isolates from North American mink and are somewhat similar to isolates of V. mustelae (Gmelin, 1790) from European mink (Lee et al. 2016; Lehman et al. 2019).

●●●●●●●● Anoplocephalidae Cholodkovsky, 1902

Genus Bertiella Stiles & Hassall, 1902

Bertia Blanchard, 1891

Bertiella mucronotata (Meyner, 1895)

Geographic distribution. South America, Caribbean (Sapp and Bradbury 2020).

Natural hosts. First intermediate hosts are oribatid mites. Definitive hosts are New World monkeys. Zoonotic in humans (Sapp and Bradbury 2020).

Route of infection. Ingestion of cysticercoids in infected mite intermediate host (Sapp and Bradbury 2020).

Site in human host. Small intestine (Sapp and Bradbury 2020).

Bertiella studeri (Blanchard, 1891)

Geographic distribution. Africa, Asia (Sapp and Bradbury 2020).

Natural hosts. First intermediate hosts are oribatid mites. Definitive hosts are Old World monkeys and non-human apes. Zoonotic in humans (Sapp and Bradbury 2020).

Route of infection. Ingestion of cysticercoids in infected mite intermediate host (Sapp and Bradbury 2020).

Site in human host. Small intestine (Sapp and Bradbury 2020).

Genus Inermicapsifer Janicki, 1910

Inermicapsifer madagascariensis (Davaine, 1870)

Acanthocephala arvicanthidis Kofend, 1917

Raillietina cubensis Kouri, 1938

Geographic distribution. Sub-Saharan Africa, South America, West Indies, Southeast Asia (Goldsmid and Muir 1972; Sapp and Bradbury 2020).

Natural hosts. Intermediate hosts are not known, but presumed to be terrestrial arthropods. Definitive hosts are rodents and hyraxes. Zoonotic in humans (Goldsmid and Muir 1972; Sapp and Bradbury 2020).

Route of infection. Ingestion of cysticercoids in infected arthropod intermediate host (Sapp and Bradbury 2020).

Site in human host. Small intestine (Sapp and Bradbury 2020).

Genus Mathevotaenia Akhumyan, 1946

Mathevotaenia symmetrica (Baylis, 1927)

Geographic distribution. Europe, Asia (Lamon and Greer 1986).

Natural hosts. Intermediate hosts are suspected as being arthropods. Definitive hosts are rodents. Zoonotic in humans (Lamon and Greer 1986).

Route of infection. Presumably, ingestion of cysticercoids in infected arthropod intermediate host (Lamon and Greer 1986).

Site in human host. Small intestine (Lamon and Greer 1986).

Genus Moniezia Blanchard, 1891

Moniezia expansa (Rudolphi, 1810)

Geographic distribution. Worldwide (single human case from Egypt) (Elliott 1986; el-Shazly et al. 2004).

Natural hosts. Intermediate hosts are mites. Definitive hosts are sheep, goats, cattle. Zoonotic in humans (Elliott 1986; el-Shazly et al. 2004).

Route of infection. Presumably, ingestion of cysticercoids in infected arthropod intermediate host (el-Shazly et al. 2004).

Site in human host. Small intestine (el-Shazly et al. 2004).

●●●●●●●● Davaineidae Braun, 1900

Genus Raillietina Fuhrman, 1920

Raillietina celebensis (Janicki, 1902)

Taenia asiatica von Linstow, 1891

Taenia formosana Akashi, 1916

Raillietina funerebris Meggitt & Subramanian, 1927

Raillietina garrisoni Tubangui, 1931

Raillietina sinensis Hsu, 1935

Raillietina murium Joyeux & Baer, 1938

Geographic distribution. Asia, Australia (Baer and Sandars 1956; Sapp and Bradbury 2020).

Natural hosts. Intermediate hosts are invertebrates, including insects (primarily ants and beetles) and terrestrial mollusks. Definitive hosts are rodents and shrews. Zoonotic in humans (Baer and Sandars 1956; Sapp and Bradbury 2020).

Route of infection. Ingestion of cysticercoids in infected arthropod intermediate host (Baer and Sandars 1956; Sapp and Bradbury 2020).

Site in human host. Small intestine (Baer and Sandars 1956; Sapp and Bradbury 2020).

Raillietina demerariensis (Daniels, 1895)

Raillietina quitensis Leon, 1935

Raillietina brumpti Doilfus, 1939

Raillietina equatoriensis Dollfus, 1939

Raillietina leoni Dollfus, 1939

Raillietina luisaleoni Dollfus, 1939

Raillietina halli Perez-Vigueras, 1934

Geographic distribution. South America, Caribbean (Baer and Sandars 1956; Sapp and Bradbury 2020).

Natural hosts. Intermediate hosts are invertebrates, including insects (primarily ants and beetles) and terrestrial mollusks. Definitive hosts are rodents; non-human primates may serve as reservoir hosts. Zoonotic in humans (Baer and Sandars 1956; Sapp and Bradbury 2020).

Route of infection. Ingestion of cysticercoids in infected arthropod intermediate host (Baer and Sandars 1956; Sapp and Bradbury 2020).

Site in human host. Small intestine (Baer and Sandars 1956; Sapp and Bradbury 2020).

Raillietina siriraji Chandler & Pradatsundarasar, 1957

Geographic distribution. Thailand (Sapp and Bradbury 2020).

Natural hosts. Intermediate hosts are invertebrates, including insects (primarily ants and beetles). Definitive hosts are rodents. Zoonotic in humans (Sapp and Bradbury 2020).

Route of infection. Ingestion of cysticercoids in infected arthropod intermediate host (Sapp and Bradbury 2020).

Site in human host. Small intestine (Sapp and Bradbury 2020).

●●●●●●●● Mesocestoididae Fuhrmann, 1907

Genus Mesocestoides Valliant, 1863

Mesocestoides lineatus (Goeze, 1782)

Geographic distribution. Europe and Asia (Sapp and Bradbury 2020).

Natural hosts. The complete life cycle and presumed number of hosts is not completely understood. The presumed first intermediate host is believed to be an arthropod. The second intermediate hosts are a variety of vertebrates, including small mammals, birds, reptiles, and amphibians. Definitive hosts are carnivores, including foxes, wolves, raccoon dogs, and European badgers. Zoonotic in humans (Padgett and Boyce 2004; Sapp and Bradbury 2020).

Route of infection. Unknown; presumed to be ingestion of tetrathyridia in meat and viscera of infected second intermediate hosts (Sapp and Bradbury 2020).

Site in human host. Small intestine (Sapp and Bradbury 2020).

Mesocestoides variabilis Mueller, 1928

Geographic distribution. North America (Sapp and Bradbury 2020).

Natural hosts. The complete life cycle and presumed number of hosts is not completely understood. The presumed first intermediate host is believed to be an arthropod. The second intermediate hosts are a variety of vertebrates, including small mammals, birds, reptiles, and amphibians. Definitive hosts include wild and domestic canids and felids, mustelids, and opossums. Zoonotic in humans (Padgett and Boyce 2004; Sapp and Bradbury 2020).

Route of infection. Unknown; presumed to be ingestion of tetrathyridia in meat and viscera of infected second intermediate hosts (Sapp and Bradbury 2020).

Site in human host. Small intestine (Sapp and Bradbury 2020).

●●●●● Trematoda Rudolphi, 1808

●●●●●● Digenea Carus, 1863

●●●●●●● Diplostomida Olson et al., 2003

●●●●●●●● Diplostomata Olson et al., 2003

●●●●●●●●● Brachylaeimidae Joyeux & Foley, 1930

Genus Brachylaeima Dujardin, 1843

Brachylaeima cribbi Butcher & Grove, 2001

Geographic distribution. Australia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are terrestrial snails in the genus Theba. Second intermediate hosts are land snails in the genus Cernualla. Definitive hosts include a variety of birds, mammals, and reptiles. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected snail intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●●● Cyathocotylidae Mühling, 1898

Genus Prohemistomum Odhner, 1913

Prohemistomum vivax (Sonsino, 1892)

Geographic distribution. Europe, North Africa, Middle East (Nasr 1941; Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Cleopatra. Second intermediate hosts are various brackish water and freshwater fish. Definitive hosts are felids, canids, and birds. Zoonotic in humans (Nasr 1941; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate hosts (Nasr 1941; Chai and Jung 2020)

Site in human host. Small intestine (Nasr 1941; Chai and Jung 2020).

●●●●●●●●● Diplostomidae Poirier, 1886

Genus Alaria Schrank, 1788

Alaria americana Hall & Wigdor, 1918

Geographic distribution. North America (Möhl et al. 2009).

Natural hosts. First intermediate hosts are snails in the genera Planorbis, Heliosoma, Lymnea, and Anisus. Second intermediate hosts are amphibians; many vertebrate animals can serve as paratenic hosts. Definitive hosts are carnivores. Zoonotic in humans (Möhl et al. 2009).

Route of infection. Ingestion of metacercariae in undercooked game meat (Möhl et al. 2009).

Site in human host. Subcutaneous tissues, eyes, lungs, disseminated infections (Freeman et al. 1976; Möhl et al. 2009).

Genus Fibricola Dubois, 1932

Fibricola cratera (Barker & Noll, 1915)

Geographic distribution. North America (Hoffman 1955; Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Physa. Second intermediate hosts are amphibians. Definitive hosts are rodents and shrews. Zoonotic in humans (Hoffman 1955; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected amphibian intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Neodiplostomum Railliet, 1919

Neodiplostomum seoulense Seo et al., 1964

Geographic distribution. China, South Korea (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genera Hippeutis and Segmentina. Second intermediate hosts are amphibians; snakes can serve as paratenic hosts. Definitive hosts are rodents and humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected reptile and amphibian intermediate and paratenic hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●●● Strigeidae Railliet, 1919

Genus Cotylurus Szidat, 1928

Cotylurus japonicus Ishii, 1932

Geographic distribution. Central and Southeast Asia, Russia, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown but hypothesized to be freshwater snails. Second intermediate hosts are unknown but presumed to be freshwater snails. Definitive hosts are ducks. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected insect intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●●● Schistosomatidae Stiles & Hassall, 1898

Genus Schistosoma Weinland, 1858

Schistosoma bovis (Bilharz, 1852)

Geographic distribution. Southern Europe, Middle East, South Asia, Africa (Christensen et al. 1983).

Natural hosts. First intermediate hosts are snails in the genus Bulinus. Definitive hosts are ruminants, primarily cattle. Zoonotic in humans (Christensen et al. 1983).

Route of infection. Penetration of skin by free-swimming cercariae

Site in human host. Mesenteric veins of the large intestine (Chunge et al. 1986; Mouchet et al. 1988)

Notes. Human infections with hybrids of S. bovis and S. haematobium have been confirmed using molecular methods (Oleaga et al. 2019).

Schistosoma guineensis Pagès et al., 2003

Schistosoma intercalatum, Guinea strain

Geographic distribution. West Africa (Webster et al. 2006).

Natural hosts. First intermediate hosts are snails in the genus Bulinus. Definitive hosts are humans, rodents, ruminants (Webster et al. 2006).

Route of infection. Penetration of skin by free-swimming cercariae (Webster et al. 2006).

Site in human host. Mesenteric veins of the large intestine (Webster et al. 2006).

Schistosoma haematobium (Bilharz, 1852)

Geographic distribution. Africa, isolated regions of the Middle East (Colley et al. 2014; Gautret et al. 2015).

Natural hosts. First intermediate hosts are snails in the genus Bulinus. Definitive hosts are humans (Colley et al. 2014).

Route of infection. Penetration of skin by free-swimming cercariae (Colley et al. 2014).

Site in human host. Venous plexus of the urinary bladder (Colley et al. 2014).

Notes. Human infection of hybrids of S. haematobium and S. bovis have been documented in Corsica, France (Oleaga et al. 2019).

Schistosoma intercalatum Fisher, 1934

Geographic distribution. Democratic Republic of the Congo (Webster et al. 2006; Colley et al. 2014).

Natural hosts. First intermediate hosts are snails in the genus Bulinus. Definitive hosts are humans, rodents, ruminants (Colley et al. 2014).

Route of infection. Penetration of skin by free-swimming cercariae (Colley et al. 2014).

Site in human host. Mesenteric veins of the large intestine (Colley et al. 2014).

Schistosoma japonicum (Katsurada, 1904)

Geographic distribution. China, Philippines, Indonesia (Sulawesi) (Colley et al. 2014).

Natural hosts. First intermediate hosts are snails in the genus Oncomelania. Definitive hosts include a variety of mammals, including canids, felids, pigs, ruminants, rodents, and humans (Colley et al. 2014).

Route of infection. Penetration of skin by free-swimming cercariae (Colley et al. 2014).

Site in human host. Mesenteric veins of the small and large intestine (Colley et al. 2014).

Schistosoma mansoni Sambon, 1907

Geographic distribution. Sub-Saharan Africa, South America, Caribbean, parts of the Arabian Peninsula (Colley et al. 2014).

Natural hosts. First intermediate hosts are snails in the genus Biomphalaria. Definitive hosts are humans, occasionally non-human primates (Colley et al. 2014).

Route of infection. Penetration of skin by free-swimming cercariae (Colley et al. 2014).

Site in human host. Mesenteric veins of the large intestine (Colley et al. 2014).

Schistosoma mattheei Veglia & LeRoux, 1929

Geographic distribution. Africa, Middle East (Christensen et al. 1983).

Natural hosts. First intermediate hosts are snails in the genus Bulinus. Definitive hosts are wild and domestic ruminants. Zoonotic in humans (Christensen et al. 1983).

Route of infection. Penetration of skin by free-swimming cercariae (Christensen et al. 1983).

Site in human host. Presumed to be venous plexus of the urinary bladder (Wolmarans et al. 1990; Cnops et al. 2020).

Notes. Reports of patent, egg-producing human infections with S. mattheei are most likely a result of hybridization of this species with S. haematobium. Dead-end acute infections with S. mattheei × S. haematobium have been confirmed using molecular methods (Kruger and Evans 2009; Cnops et al. 2020).

Schistosoma mekongi Voge et al., 1978

Geographic distribution. Mekong River Valley of Cambodia and Laos (Colley et al. 2014).

Natural hosts. First intermediate host is the snail Neotricula aperta. Definitive hosts include a variety of mammals, including canids, felids, pigs, ruminants, rodents, and humans (Colley et al. 2014).

Route of infection. Penetration of skin by free-swimming cercariae (Colley et al. 2014).

Site in human host. Mesenteric veins of the large intestine (Colley et al. 2014).

Cercarial dermatitis

Many species of avian, and some mammalian, schistosomes cause a limited cutaneous reaction in humans referred to as cercarial dermatitis (or “swimmer’s itch”). The identity of causative agents is typically inferred via environmental investigations following outbreaks and may or may not be identified to species level; only the major genera are listed here:

Genus Anserobilharzia Brandt et al., 2013

Geographic distribution. Northern Hemisphere (Brant et al. 2013).

Natural hosts. Intermediate hosts are freshwater snails in the family Planorbidae. Definitive hosts are charadriiform birds. Zoonotic in humans (Brant et al. 2013; Horák et al. 2015).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

Genus Austrobilharzia Johnston, 1917

Geographic distribution. Northern Hemisphere, Australia (Farley 1971).

Natural hosts. Intermediate hosts are freshwater snails in the family Planorbidae. Definitive hosts are charadriiform birds. Zoonotic in humans (Farley 1971).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

Genus Bilharziella Looss, 1899

Geographic distribution. Europe (Prüter et al. 2017).

Natural hosts. Intermediate hosts are freshwater snails in the family Planorbidae. Definitive hosts are waterfowl and other wading birds. Zoonotic in humans (Prüter et al. 2017).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

Genus Bivitellobilharzia Vogel & Minning, 1940

Geographic distribution. Africa, Asia (Devkota et al. 2014).

Natural hosts. Snail intermediate hosts are unknown. Definitive hosts are elephants and rhinoceroses. Zoonotic in humans (Devkota et al. 2014).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

Genus Gigantobilharzia Odhner, 1910

Geographic distribution. North America (McDonald 1981).

Natural hosts. Intermediate hosts are freshwater snails in the family Physidae. Definitive hosts are passerine birds. Zoonotic in humans (McDonald 1981).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

Genus Heterobilharzia Price, 1929

Geographic distribution. North America (Graham et al. 2021).

Natural hosts. Intermediate hosts are freshwater snails in the family Lymnaeidae. Definitive hosts are various mammals, including carnivores and marsupials. Zoonotic in humans (Graham et al. 2021).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

Genus Ornithobilharzia Odhner, 1912

Geographic distribution. Worldwide (Farley 1971)

Natural hosts. Intermediate hosts are marine snails in the family Batillaridae. Definitive hosts are various birds and mammals. Zoonotic in humans (Farley 1971).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

Genus Trichobilharzia Skrjabin & Zakharow, 1920

Geographic distribution. Worldwide (Horák et al. 2002).

Natural hosts. Intermediate hosts are freshwater snails in the families Lymnaeidae and Physidae. Definitive hosts are waterfowl. Zoonotic in humans (Horák et al. 2002).

Route of infection. Penetration of skin by free-swimming cercariae (Horák et al. 2015).

Site in human host. Skin (Horák et al. 2015).

●●●●●●● Plagiorchiida La Rue, 1957

●●●●●●●● Bucephalata La Rue, 1926

●●●●●●●●● Gymnophallidae Odhner, 1905

Genus Gymnophalloides Fujita, 1925

Gymnophalloides seoi Chai et al., 2003

Geographic distribution. South Korea (Lee and Chai 2001; Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are oysters in the genus Crassostrea. Definitive hosts are oystercatchers (Haematopus). Zoonotic in humans (Lee and Chai 2001; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected oyster intermediate hosts (Lee and Chai 2001; Chai and Jung 2020),

Site in human host. Small intestine (Lee and Chai 2001; Chai and Jung 2020).

●●●●●●●● Echinostomata La Rue, 1926

●●●●●●●●● Himasthlidae Odhner, 1910

Genus Acanthoparyphium Dietz, 1909

Acanthoparyphium tyosenense Yamaguti, 1939

Geographic distribution. Korea, Japan (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are marine gastropods. The second intermediate hosts are brackish water bivalves. Definitive hosts are ducks. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected bivalves (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Genus Himasthla Dietz, 1909

Himasthla muehlensi Vogel, 1933

Geographic distribution. North America, Colombia (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown, presumed to be marine gastropods. Second intermediate hosts are presumed to be marine clams and mussels. Definitive hosts are birds. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected mollusk intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

●●●●●●●●● Echinochasmidae Odhner, 1910

Genus Echinochasmus Dietz, 1909

Echinochasmus caninus (Verma, 1935)

Geographic distribution. Southeast Asia, India (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are freshwater fish in the genus Macropodus. Definitive hosts are wild and domestic canids. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate host (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinochasmus fujianensis Chen, in Chen et al., 1992

Geographic distribution. China (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Bellamya Second intermediate hosts are freshwater fish in the genera Pseudorasbora and Cyprinus. Definitive hosts are wild and domestic canids and felids, pigs, and rodents. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate host (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinochastmus japonicus Tanabe, 1926

Geographic distribution. Southeast Asia, Japan (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails, including the genus Parafossarulis. Second intermediate hosts are various freshwater fish. Definitive hosts are felids, insectivores, and birds. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate host (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinochasmus jiufoensis Liang & Ke, 1988

Geographic distribution. China (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are presumed to be freshwater fish or mollusks. Definitive hosts are felids, canids, and pigs. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate host (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinochasmus liliputanus (Looss, 1896)

Geographic distribution. China, Middle East, North Africa (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Parafossarulus. Second intermediate hosts are freshwater fish in the genera Pseudorasbora and Carassius. Definitive hosts are felids, canids, raccoons, and badgers. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate fish host or water contaminated with metacercariae (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinochasmus perfoliatus (Ratz, 1908)

Geographic distribution. Southeast Asia, Russia, Europe, North Africa (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are various freshwater snails (Parafossarulus, Bithynia, Lymnaea). Second intermediate hosts are various freshwater fish (Zacco, Carassius, Pseudorasbora). Definitive hosts are felids, canids, pigs, and birds. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate host (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

●●●●●●●●● Echinostomatidae Looss, 1899

Genus Artyfechinostomum Lane, 1915

Artyfechinostomum malayanum (Leiper, 1911)

Geographic distribution. Southeast Asia (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genera Indoplanorbis and Gyraulus. Second intermediate hosts are several freshwater snails. Definitive hosts include pigs, rodents, shrews, felids, canids. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected snail intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Artyfechinostomum oraoni Bandyopadhyay et al., 1989

Geographic distribution. India (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genus Lymnaea. Second intermediate hosts and definitive hosts are unknown; presumed zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Artyfechinostomum sufratyfex Lane, 1915

Cercaria mehrai Faruqui, 1930

Geographic distribution. India, Vietnam (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genera Indoplanorbis and Lymnaea. Second intermediate hosts include freshwater snails, fish, and amphibians. Definitive hosts are pigs, canids, and rodents. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Genus Echinoparyphium Dietz, 1909

Echinoparyphium recurvatum (von Linstow, 1873)

Geographic distribution. North America, Europe, North Africa, Middle East, Central and Southeast Asia (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genera Physa and Lymnaea. Second intermediate hosts include freshwater snails and amphibians. Definitive hosts are canids and rodents. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Genus Echinostoma Rudolphi, 1809

Echinostoma aegyptica Khalil & Abaza, 1924

Geographic distribution. North Africa, Middle East, Southeast Asia, Japan (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First and second intermediate hosts are unknown. Definitive hosts are rats. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinostoma angustitestes Wang, 1977

Geographic distribution. China (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are presumed to be freshwater snails. Second intermediate hosts are freshwater fish. Definitive hosts are dogs and livestock. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinostoma cinetorchis Ando & Ozaki, 1923

Geographic distribution. Southeast Asia, Japan (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genera Hippeutis and Segmentina. Second intermediate hosts include freshwater snails, fish (Misgurnus), and amphibians. Definitive hosts are rats. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinostoma ilocanum (Garrison, 1908)

Geographic distribution. Central and Southeast Asia (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genera Gyraulus and Hippeutis. Second intermediate hosts include freshwater snails in the genera Pila and Vivaparus. Definitive hosts are rats and canids. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected snail intermediate hosts(Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinostoma lindoense Sandground & Bonne, 1940

Geographic distribution. Europe, Southeast Asia, South America (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are several genera of freshwater snails. Second intermediate hosts include freshwater snails and mussels. Definitive hosts include a variety of mammals and birds. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected mollusk intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinostoma macrorchis Ando & Ozaki, 1923

Geographic distribution. Southeast Asia, Japan (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genera Segmentina and Gyraulus. Second intermediate hosts include freshwater snails (Segmentina) and amphibians. Definitive hosts are rodents and wading birds. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine(Toledo and Esteban 2016; Chai and Jung 2020).

Echinostoma paraensei Lie & Basch, 1967

Geographic distribution. Australia, Brazil (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First and second intermediate hosts are snails in the genus Biomphalaria. Definitive hosts are rats. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected snail intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Echinostoma revolutum (Froelich, 1802)

Geographic distribution. Europe, Russia, Middle East, Central and Southeast Asia, North America (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts include several genera of freshwater snails. Second intermediate hosts include freshwater snails and clams, and amphibians. Definitive hosts are felids, canids, rodents, and birds. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Notes. Numerous nominal species are considered part of the “E. revolutum complex” or the “37-collar-spined Echinostoma complex”; taxonomic resolution of species within this group is an area of ongoing investigation.

Genus Hypoderaeum Dietz, 1909

Hypoderaeum conoideum (Bloch, 1782)

Geographic distribution. Southeast Asia, Japan, Europe, North and Central America (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts include several genera of freshwater snails. Second intermediate hosts include freshwater snails and amphibians. Definitive hosts are birds. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Genus Isthmiophora Lühe, 1909

Isthmiophora hortensis (Asada, 1926)

Geographic distribution. China, Japan, Korea (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts include freshwater snails in the genera Lymnaea and Radix. Second intermediate hosts include several genera of freshwater fish. Definitive hosts are felids, canids, and rodents. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

Isthmiophora melis (Schrank, 1788)

Geographic distribution. Europe, USA, Taiwan (Toledo and Esteban 2016; Chai and Jung 2020).

Natural hosts. First intermediate hosts freshwater snails in the genus Lymnaea. Second intermediate hosts are freshwater fish and amphibians. Definitive hosts are canids, mustelids, hedgehogs, and rodents. Zoonotic in humans (Toledo and Esteban 2016; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Toledo and Esteban 2016; Chai and Jung 2020).

Site in human host. Small intestine (Toledo and Esteban 2016; Chai and Jung 2020).

●●●●●●●●● Fasciolidae Railliet, 1895

Genus Fasciola Linnaeus, 1758

Fasciola gigantica Cobbold, 1855

Geographic distribution. Africa, Middle East, Southeast Asia, Japan (Tolan 2011; Phalee et al. 2015).

Natural hosts. First intermediate hosts are freshwater snails in the genus Lymnaea. Second intermediate hosts are aquatic plants. Definitive hosts are primarily sheep, also cattle, buffalo, goats, pigs. Zoonotic in humans (olan 2011; Phalee et al. 2015).

Route of infection. Ingestion of metacercariae on contaminated aquatic vegetation (olan 2011; Phalee et al. 2015).

Site in human host. Biliary ducts; ectopic migration to skin, brain (olan 2011; Phalee et al. 2015).

Fasciola hepatica Linnaeus, 1758

Geographic distribution. Worldwide; hot spots of endemicity for human infection include the Bolivian Altiplano, Ecuador, Peru, Cuba, Portugal, Spain, Turkey, North Africa (Nile Delta), Iran, Vietnam (Tolan 2011).

Natural hosts. First intermediate hosts are freshwater snails, particularly members of the genera Galba, Fossaria, and Pseudosuccinea. Second intermediate hosts are aquatic plants. Definitive hosts include primarily cattle and buffalo, also sheep, goats, and deer. Zoonotic in humans (Tolan 2011).

Route of infection. Ingestion of metacercariae on contaminated aquatic vegetation (Tolan 2011).

Site in human host. Biliary ducts; ectopic migration to skin, brain (Tolan 2011).

Genus Fasciolopsis Looss, 1899

Fasciolopsis buski (Lankester in Küchenmeister, 1857)

Distoma rathouisi Poirier, 1887

Fasciolopsis fuelleborni Rodenwadt, 1909

Fasciolopsis goddardi Ward, 1910

Geographic distribution. Central and Southeast Asia (Sah et al. 2019; Chai and Jung 2020).

Natural hosts. First intermediate hosts are several genera of freshwater snails, especially the genera Segmentina, Hippeutis, and Gyraulus. Second intermediate hosts are freshwater plants. Definitive hosts are pigs, rabbits, and canids. Zoonotic in humans (Ma et al. 2017; Sah et al. 2019; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae on contaminated freshwater vegetation (Sah et al. 2019; Chai and Jung 2020).

Site in human host. Small intestine (Sah et al. 2019; Chai and Jung 2020).

●●●●●●●●● Philophthalmidae Looss, 1899

Genus Philophthalmus Looss, 1899

Philophthalmus gralli Matthis & Leger, 1910

Philophthalmus anatinus Sugimoto, 1928

Philophthalmus nyrocae Yamaguti, 1934

Geographic distribution. East and Southeast Asia, North America, South America (Nollen and Kanev 1995).

Natural hosts. Intermediate hosts are snails in the genus Melanoides. Definitive hosts are birds, primarily water birds and fowl. Zoonotic in humans (Nollen and Kanev 1995).

Route of infection. Ingestion of metacercariae in water or on submerged substrates (e.g., mollusk shells, plants); also direct exposure of eyes to free-swimming cercariae in water (Nollen and Kanev 1995).

Site in human host. Eyes (Nollen and Kanev 1995).

Philophthalmus palpebrarum Looss, 1899

Geographic distribution. Middle East, North Africa (Nollen and Kanev 1995).

Natural hosts. Intermediate hosts are snails in the genus Melanoides. Definitive hosts are birds, primarily water birds and fowl. Zoonotic in humans (Nollen and Kanev 1995).

Route of infection. Ingestion of metacercariae in water or on submerged substrates (e.g., mollusk shells, plants); also direct exposure of eyes to free-swimming cercariae in water (Nollen and Kanev 1995).

Site in human host. Eyes (Nollen and Kanev 1995).

Philophthalmus lacrymosus Braun, 1902

Geographic distribution. Central and South America (Nollen and Kanev 1995).

Natural hosts. Intermediate hosts are snails in the genus Melanoides. Definitive hosts are birds, primarily water birds and fowl. Zoonotic in humans (Nollen and Kanev 1995).

Route of infection. Ingestion of metacercariae in water or on submerged substrates (e.g., mollusk shells, plants); also direct exposure of eyes to free-swimming cercariae in water (Nollen and Kanev 1995).

Site in human host. Eyes (Nollen and Kanev 1995).

●●●●●●●● Hemiurata Skrjabin & Guschanskaja, 1954

●●●●●●●●● Isoparorchiidae Travassos, 1922

Genus Isoparorchis Southwell, 1913

Leptolecithum Kobayashi, 1915

Isoparorchis hypselobagri (Billet, 1898)

Geographic distribution. Central and Southeast Asia, Russia, Australia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Melanoides. Second intermediate hosts are catfish. Definitive hosts are predator fish. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●● Opisthorchiata La Rue, 1957

●●●●●●●●● Heterophyidae Leiper, 1909

Genus Acanthotrema Travassos, 1928

Acanthotrema felis Sohn et al., 2003

Geographic distribution. Korea (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are brackish water fish in the genus Acanthogobius. Definitive hosts are felids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate host (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Apophallus Lühe, 1909

Apophallus donicus (Skrjabin & Lindtrop, 1919)

Geographic distribution. North America (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Flumenicola. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores and lagomorphs. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish intermediate host (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Ascocotyle Looss, 1899

Ascocotyle longa Ransom, 1920

Geographic distribution. North America, Europe (Chai and Jung 2020).

Natural hosts. First intermediate hosts are brackish water snails in the genus Helecobia. Second intermediate hosts are brackish water fish in the genus Mugil. Definitive hosts are canids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Centrocestus Looss, 1899

Centrocestus armatus (Tanabe, 1922)

Geographic distribution. Korea, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Semisulcospira. Second intermediate hosts are freshwater fish in the genus Zacco. Definitive hosts are wild and domestic canids and felids, rabbits, rats, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Centrocestus cuspidatus (Looss, 1896)

Geographic distribution. Southeast Asia, North Africa, Middle East (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Oncomelania. Second intermediate hosts are freshwater fish in the genus Gambusia. Definitive hosts are carnivores, rodents, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Centrocestus formosanus Nishigori, 1924

Centrocestus caninus Leiper, 1913

Geographic distribution. Southeast Asia, Central and South America, North Africa, Middle East (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Stenomelania. Second intermediate hosts are freshwater fish, including Cyclocheilichthys and Puntius. Definitive hosts are wild and domestic canids, chickens, and ducks. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Centrocestus kurokawai (Kurowawa, 1935)

Geographic distribution. Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are unknown but presumed to be freshwater fish. Definitive hosts unknown; presumed zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate host (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Cryptocotyle Lühe, 1899

Cryptocotyle lingua (Creplin, 1825)

Geographic distribution. North America, Europe, Russia, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are brackish water snails in the genus Littorina. Second intermediate hosts are brackish and freshwater fish in the genus Gobius. Definitive hosts are carnivores, rodents, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Haplorchis Looss, 1899

Haplorchis pumilio (Looss, 1896)

Geographic distribution. Central and Southeast Asia, Australia, Middle East, North Africa, Central and South America (Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genus Melania. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected freshwater fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Haplorchis taichui (Nishigori, 1924)

Monorchotrema microrchia Katsuta, 1932

Geographic distribution. Central and Southeast Asia, Hawaii, Middle East (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genera Melania and Melanoides. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected freshwater fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Haplorchis vanissimus Africa, 1938

Geographic distribution. Australia, Philippines (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are unknown but presumed to be freshwater fish. Definitive hosts are wild and domestic canids and felids and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Haplorchis yokogawai (Katsuta, 1932)

Geographic distribution. Central and Southeast Asia, Australia, Middle East, North Africa (Chai and Jung 2020).

Natural hosts. First intermediate hosts include several genera of freshwater snails. Second intermediate hosts are various freshwater fish. Definitive hosts are mammals, including cattle and carnivores. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected freshwater fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Heterophyes Cobbold, 1866

Heterophyes heterophyes (Siebold, 1853)

Heterophyes aegyptiaca Cobbold, 1866

Geographic distribution. Central and Southeast Asia, Japan, Middle East, North Africa (Chai and Jung 2020).

Natural hosts. First intermediate hosts are various freshwater snails. Second intermediate hosts are various freshwater and brackish water fish. Definitive hosts are carnivores. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Heterophyes nocens Onji & Nishio, 1916

Heterophyes katsuradai Ozaki & Asada, 1926

Geographic distribution. Korea, Japan China (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Cerithidea. Second intermediate hosts are freshwater fish in the genus Acanthogobius. Definitive hosts are wild and domestic and felids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Heterophyopsis Tubangui & Africa, 1938

Heterophyopsis continua (Onki & Nishio, 1916)

Geographic distribution. Korea, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores and birds. Zoonotic in humans(Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Metagonimus Katsurada, 1912

Metagonimus katsuradai Izumi, 1935

Geographic distribution. Japan, Russia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Semisulcospira. Second intermediate hosts are freshwater fish in the genus Tanakia. Definitive hosts are carnivores. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Metagonimus minutus Katsuta, 1932

Geographic distribution. Taiwan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are brackish water fish in the genus Mugil. Definitive hosts are unknown; presumed zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Metagonimus miyatai Saito et al., 1997

Geographic distribution. Korea, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Semisulcospira. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores, rodents, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Metagonimus takahashii Takahashi, 1929

Geographic distribution. Korea, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genera Semisulcospira and Koreanomelania. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Metagonimus yokogawai (Katsurada, 1912)

Geographic distribution. Central and Southeast Asia, Russia, Japan, Europe (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Semisulcospira. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores, rodents, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Procerovum Onji & Nishio, 1916

Procerovum calderoni (Africa & Garcia, 1935)

Geographic distribution. Egypt, Southeast Asia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are brackish water snails in the genus Sermyla. Second intermediate hosts are freshwater fish in the genus Ophiocephalis. Definitive hosts are wild and domestic canids and felids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Procerovum varium Onji & Nishio, 1916

Geographic distribution. Korea, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are brackish water snails in the genus Melanoides. Second intermediate hosts are brackish water fish in the genus Mugil. Definitive hosts are wild and domestic canids and felids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Pygidiopsis Looss, 1907

Pygidiopsis genata Looss, 1907

Geographic distribution. North Africa, Middle East, Eastern Europe, Philippines (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genera Melanoides and Melanopsis. Second intermediate hosts are various freshwater fish. Definitive hosts are carnivores, rodents, shrews, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Pygidiopsis summa Onji & Nishio, 1916

Geographic distribution. Korea, Japan, Vietnam (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are brackish water fish in the genera Mugil and Acnathogonius. Definitive hosts are wild and domestic felids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Stellantchasmus Onji & Nishio, 1916

Stellantchasmus falcatus Onji & Nishio, 1916

Geographic distribution. Central and Southeast Asia, Japan, Middle East, Australia, Hawaii (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genera Stenomelania and Thiara. Second intermediate hosts are mullets. Definitive hosts are wild and domestic canids and felids, rabbits, rats, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Stictodora Looss, 1899

Stictodora fuscata (Onji & Nishio, 1916)

Geographic distribution. Korea, Japan, Kuwait (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are brackish water fish in the genera Acanthogobius and Pseudorasbora. Definitive hosts are wild and domestic canids and felids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Stictodora lari Yamaguti, 1939

Geographic distribution. Southeast Asia, Japan, Russia, Australia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are brackish water snails, including the genus Velacumantus. Second intermediate hosts are various brackish water fish. Definitive hosts are wild and domestic canids and felids. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected fish (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●●● Opisthorchiidae Looss, 1899

Genus Amphimerus Barker, 1911

Geographic distribution. North, Central, and South America (Calvopiña et al. 2011, 2015).

Natural hosts. Intermediate hosts are various freshwater snails. Second intermediate hosts are freshwater fish. Natural hosts are a variety of mammals, birds, and reptiles, including domestic dogs and cats. Zoonotic in humans (Calvopiña et al. 2011, 2015).

Route of infection. Ingestion of metacercariae in infected fish (Calvopiña et al. 2011).

Site in human host. Liver (Calvopiña et al. 2011).

Notes. The natural hosts and species identification have not been confirmed from human isolates, most of which have been documented in Ecuador.

Genus Clonorchis Looss, 1907

Clonorchis sinensis (Cobbold, 1875)

Geographic distribution. East Asia; hot spots of endemicity for human disease include Korea, China, Taiwan, and Vietnam (Qian et al. 2012).

Natural hosts. First intermediate hosts are various genera of freshwater snails. Second intermediate host are a variety of freshwater fish, primarily cyprinids. Definitive hosts are fish-eating mammals, including wild and domestic canids and felids, mustelids, and pigs. Zoonotic in humans (Qian et al. 2012).

Route of infection. Ingestion of metacercariae in infected fish (Qian et al. 2012).

Site in human host. Biliary ducts (Qian et al. 2012).

Genus Metorchis Looss, 1899

Metorchis bilis (Braun, 1790)

Distoma albidus Braun, 1893

Distoma crassiusculus Rudolphi, 1809

Geographic distribution. Central and Eastern Europe, Russia (Mordvinov et al. 2012).

Natural hosts. First intermediate hosts include snails of the genus Bithynia. Second intermediate hosts are typically cyprinid fishes (e.g., carps, minnows). Natural definitive hosts are various fish-eating mammals and birds. Zoonotic in humans (Mordvinov et al. 2012).

Route of infection. Ingestion of metacercariae in infected fish (Mordvinov et al. 2012).

Site in human host. Biliary ducts (Mordvinov et al. 2012).

Metorchis conjunctus (Cobbold, 1860)

Geographic distribution. Northern North America (Behr et al. 1998).

Natural hosts. First intermediate hosts are freshwater snails in the genus Amnicola. Second intermediate hosts are freshwater fish, primarily members of the genus Catostomus. Definitive hosts are carnivores. Zoonotic in humans (Behr et al. 1998).

Route of infection. Ingestion of metacercariae in infected fish (MacLean et al. 1996; Behr et al. 1998).

Site in human host. Biliary ducts (MacLean et al. 1996; Behr et al. 1998).

Metorchis orientalis Tanabe, 1921

Geographic distribution. East Asia (Na et al. 2016).

Natural hosts. First intermediate hosts include snails of the genera Bithynia and Parafossarulus. Second intermediate hosts are typically cyprinid fishes (e.g., carps, minnows). Natural definitive hosts are various fish-eating mammals and birds. Zoonotic in humans (Na et al. 2016).

Route of infection. Ingestion of metacercariae in infected fish (Na et al. 2016).

Site in human host. Biliary ducts (Na et al. 2016).

Metorchis taiwanensis Morishita & Tsuchimochi, 1952

Geographic distribution. East Asia (Zhan et al. 2017).

Natural hosts. First intermediate hosts include snails of the genus Bithynia. Second intermediate hosts are typically cyprinid fishes (e.g., carps, minnows). Natural definitive hosts are various fish-eating mammals and birds. Zoonotic in humans (Zhan et al. 2017).

Route of infection. Ingestion of metacercariae in infected fish (Zhan et al. 2017).

Site in human host. Biliary ducts (Zhan et al. 2017).

Genus Opisthorchis Blanchard, 1895

Opisthorchis felineus (Rivolta, 1884)

Geographic distribution. Eastern Europe, Russia, Central Asia (Pakharukova and Mordvinov 2016).

Natural hosts. First intermediate hosts are freshwater snails in the genus Bithynia. Second intermediate hosts are various freshwater fish. Definitive hosts are mammals, primarily carnivores. Zoonotic in humans (Pakharukova and Mordvinov 2016).

Route of infection. Ingestion of metacercariae in infected fish (Pakharukova and Mordvinov 2016).

Site in human host. Biliary ducts (Pakharukova and Mordvinov 2016).

Opisthorchis viverrini (Poirier, 1886)

Geographic distribution. Southeast Asia, with high prevalence of human infection in Thailand, Laos, Vietnam, and Cambodia (Kaewpitoon et al. 2008; Suwannatrai et al. 2018).

Natural hosts. First intermediate hosts are freshwater snails in the genus Bithynia. Second intermediate hosts are various freshwater fish. Definitive hosts are wild and domestic canids and felids. Zoonotic in humans (Kaewpitoon et al. 2008; Suwannatrai et al. 2018).

Route of infection. Ingestion of metacercariae in infected fish (Kaewpitoon et al. 2008).

Site in human host. Biliary ducts (Kaewpitoon et al. 2008).

Genus Pseudamphistomum Lühe, 1908

Pseudamphistomum truncatum (Rudolphi, 1819)

Geographic distribution. Europe, Asia (Neimanis et al. 2016).

Natural hosts. First intermediate hosts are freshwater and brackish snails. Second intermediate host are freshwater, brackish, and marine fish, primarily cyprinids. Definitive hosts are carnivores, including cats, pinnipeds, and mustelids. Zoonotic in humans (Neimanis et al. 2016).

Route of infection. Ingestion of metacercariae in infected fish (Neimanis et al. 2016).

Site in human host. Biliary ducts (Neimanis et al. 2016).

●●●●●●●● Pronocephalata Olson et al., 2003

●●●●●●●●● Paramphistomidae Fischoeder, 1901

Genus Fischoederius Stiles & Goldberger, 1910

Fischoederius elongatus (Poirier, 1883)

Geographic distribution. Europe, Russia, Central and Southeast Asia, Japan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Lymnaea. Second intermediate hosts are freshwater plants. Definitive hosts are cattle, deer, goats, and sheep. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae on contaminated aquatic vegetation (Chai and Jung 2020)

Site in human host. Small intestine (Chai and Jung 2020).

Genus Gastrodiscoides Leiper, 1913

Gastrodiscoides hominis (Lewis & McConnell, 1876)

Geographic distribution. Europe, Central and Southeast Asia(Mas-Coma 2006; Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Helicorbis. Second intermediate hosts are freshwater plants, amphibians, and crayfish. Definitive hosts are pigs and humans (Mas-Coma 2006; Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Mas-Coma 2006; Chai and Jung 2020).

Site in human host. Small intestine (Mas-Coma 2006; Chai and Jung 2020).

Genus Watsonius Stiles & Goldberger, 1910

Watsonius watsoni (Conyngham, 1904)

Geographic distribution. Sub-Saharan Africa, Vietnam (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Physa. Second intermediate hosts are presumed to be freshwater vegetation. Definitive hosts are non-human primates. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae on contaminated aquatic vegetation (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●● Xiphidiata Olson et al., 2003

●●●●●●●●● Dicrocoeliidae Looss, 1899

Genus Dicrocoelium Dujardin, 1845

Dicrocoelium dendriticum (Rudolphi, 1819)

Dicrocoelium lanceolatum Stiles & Hassall, 1898

Geographic distribution. North America, Africa, Asia, Europe, Middle East (Cengiz et al. 2010).

Natural hosts. First intermediate hosts are various genera of terrestrial snails. Second intermediate hosts are ants (primarily genus Formica). Definitive hosts are ungulates, including cattle, sheep, and goats. Zoonotic in humans (Cengiz et al. 2010).

Route of infection. Ingestion of metacercariae in infected ants (Cengiz et al. 2010).

Site in human host. Bile ducts, gall bladder (Cengiz et al. 2010).

Dicrocoelium hospes Looss, 1907

Geographic distribution. West Africa (Odei 1966).

Natural hosts. First intermediate hosts are snails in the genera Achatina and Limicolaria. Second intermediate hosts are ants in the genera Dorylus and Crematogaster. Definitive hosts are ungulates, including cattle and sheep. Zoonotic in humans (Odei 1966).

Route of infection. Ingestion of infected intermediate hosts (Odei 1966).

Site in human host. Bile ducts (Odei 1966)

Notes. It is uncertain whether D. hospes causes true infection in humans. Most reported cases of the finding of eggs in stool are believed to be spurious after the consumption of infected beef liver (Wolfe 2007). The two cases from Ghana believed to be true infections are in children who denied eating beef liver (Odei 1966). True infection should be confirmed by the examination of follow-up stool specimens (Wolfe 2007).

●●●●●●●●● Lecithodendriidae Lühe, 1901

Genus Caprimolgorchis Jha, 1943

Caprimolgorchis molenkampi Lie Kian Joe, 1961

Geographic distribution. Southeast Asia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown, but hypothesized to be freshwater snails in the genera Bithynia or Zebrina. Second intermediate hosts are dragonflies and damselflies. Definitive hosts are rodents and bats. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of infected insects (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●●● Microphalidae Ward, 1901

Genus Gynaecotyla Yamaguti, 1939

Gynaecotyla squatarolae (Yamaguti, 1934)

Geographic distribution. Japan, South Korea, Taiwan (Chai and Jung 2020).

Natural hosts. First intermediate hosts are brackish water snails in the genus Batillaria. Second intermediate hosts are brackish water crabs in the genus Macrophthalmus. Definitive hosts are shorebirds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected crabs (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Genus Microphallus Ward, 1901

Microphallus brevicaeca (Africa & Garcia, 1935)

Geographic distribution. Papua New Guinea, Philippines (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are brackish water crustaceans in the genera Carcinus and Macrobrachium. Definitive hosts are birds and mammals, especially non-human primates. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected crustaceans (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●●● Phaeneropsolidae Mehra, 1935

Genus Phaneropsolus Looss, 1899

Phaneropsolus bonnei Lie Kian Joe, 1951

Geographic distribution. Central and Southeast Asia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown, but hypothesized to be freshwater snails in the genus Bithynia. Second intermediate hosts are dragonflies and damselflies. Definitive hosts are non-human primates. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of infected insects (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Phaneropsolus spinicirrus Kaewkes et al., 1991

Geographic distribution. Thailand (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are unknown, but presumed to be dragonflies and damselflies. Definitive hosts are unknown; presumed zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of infected intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●●● Plagiorchiidae Lühe, 1901

Genus Plagiorchis Lühe, 1899

Plagiorchis javensis Sandground, 1940

Geographic distribution. Indonesia (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts include snails, insects, and possibly fish. Definitive hosts are birds and bats. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Plagiorchis muris (Tanabe, 1922)

Geographic distribution. Europe, Central and Southeast Asia, Japan, North and Central America (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Lymnaea. Second intermediate hosts are freshwater insects, crustaceans, and fish. Definitive hosts are canids, felids, raccoons, rodents, bats, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Plagiorchis philippinensis Africa & Garcia, 1937

Geographic distribution. Philippines (Chai and Jung 2020).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are presumed to be aquatic insects. Definitive hosts rodents and possibly birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Plagiorchis vespertilionis (Müller, 1784)

Geographic distribution. Europe, North Africa, Central and Southeast Asia, Japan, Madagascar, North America (Chai and Jung 2020).

Natural hosts. First intermediate hosts are freshwater snails in the genus Lymnaea. Second intermediate hosts are freshwater insects. Definitive hosts are rodents and bats. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected insect intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

●●●●●●●● Troglotremata Schell, 1890

●●●●●●●●● Nanophyetidae Dollfus, 1939

Genus Nanophyetus Chapin, 1928

Nanophyetus salmincola (Chapin, 1926)

Geographic distribution. Northern North America (Chai and Jung 2020).

Natural hosts. First intermediate hosts are snails in the genus Oxytrema. Second intermediate hosts are several general of freshwater fish, especially salmonids. Definitive hosts canids, felids, raccoons, and birds. Zoonotic in humans (Chai and Jung 2020).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Chai and Jung 2020).

Site in human host. Small intestine (Chai and Jung 2020).

Nanophyetus schikhobalowi Skrjabin & Podiapolskaia, 1931

Geographic distribution. Northern Eurasia (Voronova et al. 2017; Voronova and Chelomina 2018).

Natural hosts. First intermediate hosts are snails in the genus Oxytrema. Second intermediate hosts are several general of freshwater fish, especially salmonids. Definitive hosts canids, felids, raccoons, and birds. Zoonotic in humans (Voronova et al. 2017; Voronova and Chelomina 2018).

Route of infection. Ingestion of metacercariae in infected intermediate hosts (Voronova et al. 2017; Voronova and Chelomina 2018).

Site in human host. Small intestine (Voronova et al. 2017; Voronova and Chelomina 2018).

●●●●●●●●● Paragonimidae Dollfus, 1939

Genus Paragonimus Braun, 1899

Paragonimus africanus Volker & Vogel, 1965

Geographic distribution. West Africa (Blair et al. 1999; Cumberlidge et al. 2018).

Natural hosts. First intermediate hosts are presumed to be freshwater or brackish snails, but the specific species have yet to be identified. Second intermediate hosts are freshwater crabs in the family Potamidae. Definitive hosts are carnivores and non-human primates. Zoonotic in humans (Blair et al. 1999; Cumberlidge et al. 2018).

Route of infection. Ingestion of metacercariae in infected intermediate or paratenic hosts (Blair et al. 1999; Cumberlidge et al. 2018).

Site in human host. Lungs, possibly ectopic infection at other sites (Blair et al. 1999; Cumberlidge et al. 2018).

Paragonimus heterotremus Chen & Hsia, 1964

Paragonimus tuanshansis Chung et al., 1964

Paragonimus pseudoheterotremus Waikagul et al., 2007

Geographic distribution. Southeast Asia (Yoshida et al. 2019).

Natural hosts. First intermediate hosts are freshwater snails in the superfamily Rissooidea. Second intermediate hosts are freshwater crabs in the families Potamidae and Parathelphusidae. Definitive hosts are carnivores and non-human primates. Wild boar, rodents, and deer can serve as paratenic hosts. Zoonotic in humans (Yoshida et al. 2019).

Route of infection. Ingestion of metacercariae in infected intermediate or paratenic hosts (Yoshida et al. 2019).

Site in human host. Lungs, possibly ectopic infection at other sites (Yoshida et al. 2019).

Notes. Paragonimus heterotremus is often referred to as a species complex; the status of many members as distinct and valid species is an area of ongoing investigation.

Paragonimus kellicotti Ward, 1908

Geographic distribution. Eastern and Midwestern North America (Procop 2009).

Natural hosts. First intermediate hosts are freshwater snails in the family Pomatiopsidae. Second intermediate hosts are freshwater crayfish, primarily of the family Astacidae. Definitive hosts are carnivores and marsupials. Zoonotic in humans (Procop 2009).

Route of infection. Ingestion of metacercariae in infected intermediate and paratenic hosts (Procop 2009).

Site in human host. Lungs, possibly ectopic infection at other sites (Procop 2009).

Paragonimus mexicanus Miyazaki & Ishii, 1968

Paragonimus peruvianus Miyazaki et al., 1969

Paragonimus ecuadorensis Voekler & Arzube, 1979

Geographic distribution. Central and South America (Blair et al. 1999).

Natural hosts. First intermediate hosts are freshwater and brackish snails in the families Hydrobiidae and Pomatiopsidae. Second intermediate hosts are freshwater crabs in the families Pseudothelphusidae and Trichodactylidae. Definitive hosts are carnivores and marsupials. Zoonotic in humans (Blair et al. 1999).

Route of infection. Ingestion of metacercariae in infected crustaceans (Blair et al. 1999).

Site in human host. Lungs, possibly ectopic infection at other sites (Blair et al. 1999).

Paragonimus ohirai Miyazaki, 1939

Paragonimus iloktsuensis Chen, 1940

Paragonimus sadoensis Miyazaki et al., 1968

Geographic distribution. East Asia (Blair et al. 1999; Yoshida et al. 2019).

Natural hosts. First intermediate hosts are freshwater and brackish snails in the families Assimineidae and Pomatiopsidae. Second intermediate hosts are freshwater crabs in the family Potamidae and brackish crabs in the family Grapsidae. Definitive hosts are carnivores. Zoonotic in humans (Blair et al. 1999; Yoshida et al. 2019).

Route of infection. Ingestion of metacercariae in infected intermediate or paratenic hosts (Blair et al. 1999; Yoshida et al. 2019).

Site in human host. Lungs, possibly ectopic infection at other sites (Blair et al. 1999; Yoshida et al. 2019).

Notes. Paragonimus ohirai is often referred to as a species complex; the status of many members as distinct and valid species is an area of ongoing investigation.

Paragonimus skrjabini Chen, 1959

Paragonimus miyazakii Kamo et al., 1961

Paragonimus szechuanensis Chung & Tsao, 1962

Paragonimus hueitungensis Chung et al., 1975

Paragonimus veocularis Chen & Li, 1979

Geographic distribution. East and Southeast Asia, Indian subcontinent (Blair et al. 1999; Yoshida et al. 2019).

Natural hosts. First intermediate hosts are freshwater and brackish snails in the superfamily Rissooidea. Second intermediate hosts are freshwater crabs in the families Potamidae and Parathelphusidae. Definitive hosts are carnivores. Wild boar, rodents, and deer may serve as paratenic hosts. Zoonotic in humans (Blair et al. 1999; Yoshida et al. 2019).

Route of infection. Ingestion of metacercariae in infected intermediate and paratenic hosts (Blair et al. 1999; Yoshida et al. 2019).

Site in human host. Lungs, possibly ectopic infection at other sites (Blair et al. 1999; Yoshida et al. 2019).

Notes. Paragonimus skrjabini is often referred to as a species complex; the status of many members as distinct and valid species is an area of ongoing investigation.

Paragonimus uterobilateralis Volker & Vogel, 1965

Geographic distribution. West Africa (Blair et al. 1999; Cumberlidge et al. 2018).

Natural hosts. First intermediate hosts are presumed to be freshwater or brackish snails, but the specific species have yet to be identified. Second intermediate hosts are freshwater crabs in the family Potamidae. Definitive hosts are carnivores. Zoonotic in humans (Blair et al. 1999; Cumberlidge et al. 2018).

Route of infection. Ingestion of metacercariae in infected intermediate or paratenic hosts (Blair et al. 1999; Cumberlidge et al. 2018).

Site in human host. Lungs, possibly ectopic infection at other sites (Blair et al. 1999; Cumberlidge et al. 2018).

Paragonimus westermani (Kerbert, 1878)

Distoma pulmonalis Baelz, 1880

Distoma ringeri Cobbold, 1880

Paragonimus edwardsi Gulati, 1926

Paragonimus macacae Sandosham, 1953

Paragonimus asymmetricus Chen, 1977

Paragonimus filipinus Miyazaki, 1978

Paragonimus philippinensis Ito et al., 1978

Geographic distribution. East and Southeast Asia, Indian subcontinent, Siberia (Blair et al. 1999; YBlair 2019; oshida et al. 2019).

Natural hosts. First intermediate hosts are freshwater and brackish snails in the superfamily Cerithioidea. Second intermediate hosts are freshwater crabs in the families Potamidae and Parathelphusidae. Definitive hosts are carnivores and non-human primates. Wild boar, rodents, and deer may serve as paratenic hosts. Zoonotic in humans (Blair et al. 1999; Blair 2019; Yoshida et al. 2019).

Route of infection. Ingestion of metacercariae in infected intermediate or paratenic hosts (Blair et al. 1999; Blair 2019; Yoshida et al. 2019).

Site in human host. Lungs, possibly ectopic infection at other sites (Blair et al. 1999; Blair 2019; Yoshida et al. 2019).

Notes. Paragonimus westermani is often referred to as a species complex; the status of many members as distinct and valid species is an area of ongoing investigation.

●●●●●●●●● Orchipedidae Skrjabin, 1913

Achillurbainiidae Dollfus, 1939

Genus Achillurbainia Dolffus, 1939

Poikilorchis Fain & Vandepitte, 1957

Achillurbainia congolensis (Fain & Vandepitte, 1957)

Geographic distribution. Sub-Saharan Africa (Fain and Vandepitte 1957; Nieuwenhuyse and Gatti 1968).

Natural hosts. Unknown; presumed zoonotic in humans (Fain and Vandepitte 1957; Nieuwenhuyse and Gatti 1968).

Route of infection. Unknown.

Site in human host. Subcutaneous cysts (usually near the ear), mastoid, middle ear (Fain and Vandepitte 1957; Nieuwenhuyse and Gatti 1968).

Achillurbainia nouveli Dolffus, 1939

Geographic distribution. Southeast Asia (human case from China) (Kannangara 1971).

Natural hosts. First intermediate hosts are unknown. Second intermediate hosts are freshwater crabs (Paratelphusa). Definitive hosts are leopards. Zoonotic in humans (Kannangara 1971; Kwo and Lim 1968).

Route of infection. Unknown, presumed ingestion of metacercariae in undercooked crabs (Kannangara 1971).

Site in human host. Subcutaneous cysts (near the ear) (Kannangara 1971).

Achillurbainia recondita Travassos, 1942

Geographic distribution. Central and South America (Beaver et al. 1977).

Natural hosts. Intermediate hosts unknown. Definitive hosts are opossums (Didelphis marsupialis). Zoonotic in humans (Beaver et al. 1977).

Route of infection. Unknown.

Site in human host. Peritoneal cavity (Beaver et al. 1977).

●●●● Ecdysozoa Anguinaldo et al., 1997

●●●●● Panarthropoda Nielsen, 1995

●●●●●● Arthropoda von Siebold, 1848

●●●●●●● Chelicerata Heymons, 1901

●●●●●●●● Euchelicerata Weygoldt & Paulus, 1979

●●●●●●●●● Arachnida Lamarck, 1801

●●●●●●●●●● Acari Leach, 1817

●●●●●●●●●●● Acariformes Zakhvatkin, 1952

●●●●●●●●●●●● Sarcoptiformes Reuter, 1909

●●●●●●●●●●●●● Astigmatina Canestrini, 1891

●●●●●●●●●●●●●● Acaridia Latreille, 1802

●●●●●●●●●●●●●●● Histiostomatidae Berlese, 1897

Histiostomatidae, incertae sedis

Geographic distribution. Unknown (single human case from Saudi Arabia) (Al-Arfaj et al. 2007).

Natural hosts. Unknown

Route of infection. Unknown, presumed exposure to fresh water (Al-Arfaj et al. 2007).

Site in human host. Ear (Al-Arfaj et al. 2007).

Vectored pathogens. None

Notes. Histostomatid mites were isolated from the ear of a Saudi man who travelled to the United States in 2007. The mites were reported as being an undescribed species of Histiostomatidae close to Loxantoetus (Al-Arfaj et al. 2007). At the time of this writing, the species had still not been described (Gary Mullen, pers. comm. 2020).

●●●●●●●●●●●●●●● Acaridae Latreille, 1802

Genus Sancassania Oudemans, 1916

Sancassania berlesei (Michael, 1903)

Geographic distribution. Worldwide (Timms et al. 1981).

Natural hosts. None; cause incidental infestations in humans (Timms et al. 1981).

Route of infection. Contamination from the environment.

Site in human host. Mastoid cavity, ear (Cho et al. 1999; Paleri and Ruckley 2001).

Vectored pathogens. None.

Genus Cosmoglyphus Oudemans, 1932

Geographic distribution. Worldwide (Lombert et al. 1982).

Natural hosts. None; cause incidental infestations in humans (Lombert et al. 1982).

Route of infection. Contamination from the environment.

Site in human host. Ear (Pal et al. 2018).

Vectored pathogens. None.

Notes. Isolates of Cosmoglyphus from human clinical specimens have not been characterized at the species level.

Genus Rhizoglyphus Claparédè, 1869

Geographic distribution. Worldwide (Fan and Zhang 2004).

Natural hosts. None; cause incidental infestations in humans (Fan and Zhang 2004).

Route of infection. Contamination from the environment

Site in human host. Ear (Kiakojouri et al. 2018).

Vectored pathogens. None

Notes. Rhizoglyphus from human clinical specimens have not been characterized at the species level.

●●●●●●●●●●●●●●● Chorotoglyphidae Berlese, 1897

Genus Chorotoglyphus Berlese, 1884

Chorotoglyphus arcuatus (Troupeau, 1879)

Geographic distribution. Worldwide (Abi-Akl 2017).

Natural hosts. None; cause incidental infections in humans (Abi-Akl 2017).

Route of infection. Contamination from the environment.

Site in human host. Ear (Abi-Akl 2017).

Vectored pathogens. None.

Notes. The species-level identification of C. arcuatus isolated from the ear of a man in Lebanon was considered tentative based on morphologic characteristics (Abi-Akl 2017).

●●●●●●●●●●●●●● Psoroptidia Yunker, 1955

●●●●●●●●●●●●●●● Pyroglyphidae Cunliffe, 1958

Genus Dermatophagoides Bogdanov, 1864

Dermatophagoides farinae Hughes, 1961

Geographic distribution. Worldwide, more prevalent in North America (Hart and Fain 1988).

Natural hosts. None; cause incidental infections in humans (Hart and Fain 1988).

Route of infection. Contamination from the environment.

Site in human host. Ear (Liao and Chang 2012).

Vectored pathogens. None.

Notes. The finding of D. farinae in stool (Kapoor et al. 2019) probably represents spurious passage after the incidental ingestion of mites in contaminated foodstuffs or contamination of the stool specimen. Dust mites in urine also probably represent contamination of the urine specimens (Dini and Frean 2005; Siebers 2014).

●●●●●●●●●●●●●●● Psoroptidae Canestrini, 1892

Genus Otodectes Canestrini, 1894

Otodectes cynotis (Hering, 1838)

Geographic distribution. Worldwide (Sweatman 1958).

Natural hosts. Carnivores, primarily dogs, cats, and ferrets. Zoonotic in humans (Sweatman 1958).

Route of infection. Contamination from the environment.

Site in human host. Ear (Van de Heyning and Thienpont 1977).

Vectored pathogens. None.

Genus Psoroptes Gervais, 1841

Psoroptes ovis (Hering, 1838)

Geographic distribution. Worldwide (Mazyad et al. 2001; Ken et al. 2014).

Natural hosts. Mammals, primarily sheep, but also horses, cattle, goats. Zoonotic on humans (Mazyad et al. 2001; Ken et al. 2014).

Route of infection. Contact with infected animal hosts (Mazyad et al. 2001; Ken et al. 2014).

Site in human host. Skin (Mazyad et al. 2001; Ken et al. 2014).

Vectored pathogens. None.

●●●●●●●●●●●●●●● Sarcoptidae Murray, 1877

Genus Notoedres Railliet, 1893

Notoedres cati (Hering, 1838)

Geographic distribution. Worldwide (Sivajothi et al. 2015).

Natural hosts. Cats and other felids. Zoonotic on humans (Sivajothi et al. 2015).

Route of infection. Contact with infected felid hosts (Chakrabarti 1986).

Site in human host. Skin (Chakrabarti 1986; Beck and Pfister 2006).

Vectored pathogens. None.

Genus Sarcoptes Latreille, 1802

Sarcoptes scabiei (Linnaeus, 1758)

Geographic distribution. Worldwide (Arlian and Morgan 2017; Chandler and Fuller 2019).

Natural hosts. Humans (other animals have their own varieties and subspecies) (Arlian and Morgan 2017; Chandler and Fuller 2019).

Route of infection. Direct person-to-person contact or contaminated fomites (Arlian and Morgan 2017; Chandler and Fuller 2019).

Site in human host. Skin (Arlian and Morgan 2017; Chandler and Fuller 2019).

Vectored pathogens. None.

Genus Trixacarus Sellnick, 1944

Trixacarus caviae Fain et al., 1972

Geographic distribution. Worldwide (Dorrestein and Van Bronswijk 1979).

Natural hosts. Domestic Guinea pigs. Zoonotic on humans (Dorrestein and Van Bronswijk 1979).

Route of infection. Contact with infected Guinea pigs (Dorrestein and Van Bronswijk 1979).

Site in human host. Skin (Dorrestein and Van Bronswijk 1979).

Vectored pathogens. None.

●●●●●●●●●●●● Trombidiformes Reuter, 1909

●●●●●●●●●●●●● Prostigmata Kramer, 1877

●●●●●●●●●●●●●● Trombidoidea Leach, 1815

●●●●●●●●●●●●●●● Trombiculidae Ewing, 1929

Genus Eutrombicula Ewing, 1938

Eutrombicula alfreddugesi (Oudemans, 1910)

Geographic distribution. Western Hemisphere (Diaz 2009).

Natural hosts. Mammals and birds. Zoonotic on humans as incidental hosts (Diaz 2009).

Route of infection. Exposure to larvae in the environment (Diaz 2009).

Site in human host. Skin (Diaz 2009).

Vectored pathogens. None.

Eutrombicula sarcia (Womersley, 1944)

Geographic distribution. Asia, Australia (Diaz 2009).

Natural hosts. Mammals and birds. Zoonotic on humans as incidental hosts (Diaz 2009).

Route of infection. Exposure to larvae in the environment (Diaz 2009).

Site in human host. Skin.

Vectored pathogens. None.

Genus Leptotrombidium Nagayo et al., 1916

Leptotrombidium akamushi (Brumpt, 1910)

Geographic distribution. Japan (Diaz 2009; Elliott et al. 2019).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Diaz 2009; Elliott et al. 2019).

Route of infection. Exposure to larvae in the environment (Diaz 2009; Elliott et al. 2019).

Site in human host. Skin.

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Diaz 2009; Elliott et al. 2019).

Leptotrombidium arenicola (Traub, 1960)

Geographic distribution. Malaysia (Diaz 2009; Elliott et al. 2019).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Diaz 2009; Elliott et al. 2019).

Route of infection. Exposure to larvae in the environment (Diaz 2009; Elliott et al. 2019).

Site in human host. Skin.

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Diaz 2009; Elliott et al. 2019).

Leptotrombidium deliense (Walch, 1922)

Geographic distribution. Southeast Asia, Japan, Philippines, Australia, Pacific Islands (Lv et al. 2018).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Lv et al. 2018).

Route of infection. Exposure to larvae in the environment (Lv et al. 2018).

Site in human host. Skin.

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Lv et al. 2018).

Leptotrombidium fletcheri (Womersley & Heaslip, 1943)

Geographic distribution. Malaysia (Diaz 2009; Elliott et al. 2019).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Diaz 2009; Elliott et al. 2019)

Route of infection. Exposure to larvae in the environment (Diaz 2009; Elliott et al. 2019).

Site in human host. Skin.

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Diaz 2009; Elliott et al. 2019).

Leptotrombidium pallidum (Nagayo et al., 1919)

Geographic distribution. Japan (Diaz 2009; Elliott et al. 2019).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Diaz 2009; Elliott et al. 2019).

Route of infection. Exposure to larvae in the environment (Diaz 2009; Elliott et al. 2019).

Site in human host. Skin

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Diaz 2009; Elliott et al. 2019).

Leptotrombidium pavlovskyi (Schluger, 1948)

Geographic distribution. Eastern Russia (Diaz 2009; Elliott et al. 2019).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Diaz 2009; Elliott et al. 2019).

Route of infection. Exposure to larvae in the environment (Diaz 2009; Elliott et al. 2019).

Site in human host. Skin

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Diaz 2009; Elliott et al. 2019).

Leptotrombidium scutellaris (Nagayo et al., 1921)

Geographic distribution. Japan (Diaz 2009; Elliott et al. 2019).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Diaz 2009; Elliott et al. 2019).

Route of infection. Exposure to larvae in the environment (Diaz 2009; Elliott et al. 2019).

Site in human host. Skin

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Diaz 2009; Elliott et al. 2019).

Genus Neotrombicula Hirst, 1925

Neotrombicula autumnalis (Shaw, 1790)

Geographic distribution. Europe (Schöler et al. 2006).

Natural hosts. Mammals and birds. Zoonotic on humans as incidental hosts (Schöler et al. 2006).

Route of infection. Exposure to larvae in the environment (Diaz 2009).

Site in human host. Skin.

Vectored pathogens. None.

Genus Schoengastiella Hirst, 1915

Schoengastiella ligula Radford, 1946

Geographic distribution. South Asia (Tilak et al. 2011; Luce-Fedrow et al. 2018).

Natural hosts. Rodents and insectivores. Zoonotic on humans as incidental hosts (Tilak et al. 2011; Luce-Fedrow et al. 2018).

Route of infection. Exposure to larvae in the environment (Tilak et al. 2011; Luce-Fedrow et al. 2018).

Site in human host. Skin

Vectored pathogens. Orientia tsutsugamushi (Oriental scrub typhus) (Tilak et al. 2011; Luce-Fedrow et al. 2018).

●●●●●●●●●●●●●● Cheyletoidea Leach, 1815

●●●●●●●●●●●●●●● Cheyletidae Leach, 1815

Genus Cheyletiella Canestrini, 1886

Cheyletiella blakei Smikey, 1970

Geographic distribution. Worldwide (Keh and Lane 1987; Wagner and Stallmeister 2000).

Natural hosts. Cats. Zoonotic on humans as incidental hosts (Keh and Lane 1987; Wagner and Stallmeister 2000).

Route of infection. Exposure to infected cats (Keh and Lane 1987; Wagner and Stallmeister 2000).

Site in human host. Skin (Keh and Lane 1987; Wagner and Stallmeister 2000).

Vectored pathogens. None.

Cheyletiella parasitovorax Mégnin, 1877

Geographic distribution. Worldwide (Harcourt-Brown 2002).

Natural hosts. Rabbits. Zoonotic on humans as incidental hosts (Harcourt-Brown 2002).

Route of infection. Exposure to infected rabbits (Milman and Dik 2017).

Site in human host. Skin (Milman and Dik 2017).

Vectored pathogens. None.

Cheyletiella yasguri Smiley, 1965

Geographic distribution. Worldwide (Foxx and Ewing 1969).

Natural hosts. Dogs. Zoonotic on humans as incidental hosts (Foxx and Ewing 1969).

Route of infection. Exposure to infected dogs (Powell et al. 1977).

Site in human host. Skin (Powell et al. 1977).

Vectored pathogens. None.

●●●●●●●●●●●●●●● Demodecidae Nicolet, 1855

Genus Demodex Owen, 1843

Demodex brevis Akbulatova, 1963

Geographic distribution. Worldwide (Rather and Hassan 2014).

Natural hosts. Humans (Rather and Hassan 2014).

Route of infection. Direct person-to-person contact (Rather and Hassan 2014).

Site in human host. Skin, sebaceous glands (Rather and Hassan 2014).

Vectored pathogens. None.

Demodex folliculorum Simon, 1842

Geographic distribution. Worldwide (Rather and Hassan 2014).

Natural hosts. Humans (Rather and Hassan 2014).

Route of infection. Direct person-to-person contact (Rather and Hassan 2014).

Site in human host. Skin, hair follicles (Rather and Hassan 2014).

Vectored pathogens. None.

●●●●●●●●●●●●●● Tarsonemoidea Kramer, 1877

●●●●●●●●●●●●●●● Pyemotidae Oudemans, 1937

Genus Pyemotes Amerling, 1861

Pyemotes herfsi (Oudemans, 1936)

Geographic distribution. North America, Europe, North Africa, India, Australia (Broce et al. 2006).

Natural hosts. Insects. Zoonotic on humans as incidental hosts (Broce et al. 2006).

Route of infection. Environmental exposure (Broce et al. 2006).

Site in human host. Skin (Broce et al. 2006).

Vectored pathogens. None.

Pyemotes tritici (LaGrèze-Fossat & Montagné, 1851)

Geographic distribution. Worldwide (Yu et al. 2010).

Natural hosts. Insects. Zoonotic on humans as incidental hosts (Yu et al. 2010).

Route of infection. Environmental exposure (Rosen et al. 2002).

Site in human host. Skin (Rosen et al. 2002).

Vectored pathogens. None.

Pyemotes ventricosus (Newport, 1850)

Geographic distribution. Southern Europe (Moser 1975).

Natural hosts. Insects. Zoonotic on humans as incidental hosts (Moser 1975).

Route of infection. Environmental exposure (Diaz 2009).

Site in human host. Skin (Diaz 2009).

Vectored pathogens. None.

●●●●●●●●●●● Parasitiformes Leach, 1815

●●●●●●●●●●●● Ixodoidea Leach, 1815

●●●●●●●●●●●●● Ixodidae Koch, 1844

Genus Amblyomma Koch, 1844

Amblyomma americanum (Linnaeus, 1758)

Ixodes unipunctata Packard, 1869

Geographic distribution. Eastern North America (Cooley 1944; Guglielmone and Robbins 2018).

Natural hosts. Many birds and mammals, including humans (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Ehrlichia chaffeensis (human monocytic ehrlichiosis), E. ewingii (human granulocytic ehrlichiosis), Francisella tularensis (tularemia), Heartland virus, Bourbon virus; also implicated in alpha-gal syndrome and Southern Tick-Associated Rash Illness (STARI) (Madison-Antenucci et al. 2020).

Amblyomma aureolatum (Pallas, 1772)

Amblyomma striatum Koch, 1844

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including carnivores and rodents, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia rickettsii (Rocky Mountain Spotted Fever) (Szabó et al. 2013).

Amblyomma babirussae Schülze, 1933

Geographic distribution. Indonesia (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including pigs, bovids, deer, carnivores, and rodents. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma brasiliense Aragão, 1908

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Several mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma breviscutatum Neumann, 1899

Amblyomma cyprium Koch & Neumann, 1899

Amblyomma cyprium aeratipes Schülze, 1932

Geographic distribution. Southeast Asia, Australia, Pacific Islands (Guglielmone and Robbins 2018).

Natural hosts. Immature stages primarily on rodents and small birds. Adults are primarily on mammals, including bovids, deer, pigs, horses. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma cajennense (Fabricius, 1787)

Geographic distribution. Southern United States, Central and South America, Caribbean (Cooley 1944; Martins et al. 2016; Guglielmone and Robbins 2018).

Natural hosts. Many mammals, including humans, and birds (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma calcartum Neumann, 1899

Geographic distribution. Central and South America, Caribbean (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily anteaters; also birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma clypeolatum Neumann, 1899

Geographic distribution. India, Sri Lanka, Myanmar (Liyanaarachchi et al. 2015).

Natural hosts. Reptiles. Zoonotic on humans (Liyanaarachchi et al. 2015; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma coelebs Neumann, 1899

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma cohaerens Dönitz, 1909

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Primarily bovids, but also other mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma cordiferum Neumann, 1899

Geographic distribution. Southeast Asia (Audy 1960).

Natural hosts. Immature stages are primarily on rodents. Adults are on reptiles and ungulates. Zoonotic on humans (Audy 1960).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Notes. The single record of A. cordiferum from a human in Malaysia (Audy 1960) is considered a tentative identification (Guglielmone and Robbins 2018).

Amblyomma dissimile Koch, 1844

Geographic distribution. North, Central, and South America and Caribbean (Cooley 1944; Guglielmone and Robbins 2018).

Natural hosts. Primarily reptiles and amphibians, but also a variety of mammals and birds. Zoonotic on humans (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma dubitatum Neumann, 1899

Amblyomma cooperi Nuttall & Warburton, 1908

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Primarily rodents, but also other mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma falsomarmoreum Tonelli-Rondelli, 1935

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Reptiles, occasionally other mammals. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma fuscum Neumann, 1907

Geographic distribution. Brazil (Guglielmone and Robbins 2018).

Natural hosts. Immature stages on mammals, including rodents, carnivores, and marsupials. Adults usually on reptiles and amphibians. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma gemma Dönitz, 1909

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Immature stages on small mammals and birds. Adults primarily on bovids, pigs, camels, and horses, but also other mammals, large birds, and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma geomydae (Cantor, 1847)

Amblyomma malayanum Neumann, 1906

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Immature stages on a variety of small mammals, birds, and reptiles. Adults primarily on tortoises, but also several mammals, including pigs, bovids, deer. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma hadanii Nava et al., 2014

Geographic distribution. Argentina (Guglielmone and Robbins 2018).

Natural hosts. Primarily bovids, tapirs, horses, also carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma hebraeum Koch, 1844

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including bovids, goats, sheep, other ruminants, and humans; occasionally birds and reptiles (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia africae (African tick bite fever) (Jongejan et al. 2020).

Amblyomma incisum Neumann, 1906

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily tapirs, but also rodents, deer, and carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma inoratum (Banks, 1909)

Geographic distribution. North and Central America (Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma integrum Karsch, 1879

Geographic distribution. India, Sri Lanka (Guglielmone and Robbins 2018).

Natural hosts. Primarily bovids, but also other mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin, ears (Dilrukshi et al. 2004).

Vectored pathogens. None.

Amblyomma javanense (Supino, 1897)

Aponomma sublaeve Neumann, 1899

Geographic distribution. Central, Southeastern Asia (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily pangolins, but also rodents, and carnivores, and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma latepunctatum Tonelli-Rondelli, 1939

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily tapirs and peccaries, also marsupials and rodents. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma latum Koch, 1844

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Primarily reptiles, also amphibians, rodents, and shrews. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Ambylomma lepidum Dönitz, 1909

Geographic distribution. Sub-Saharan Africa, Middle East (Guglielmone and Robbins 2018).

Natural hosts. Primarily bovids, but also other mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma limbatum Neumann, 1899

Geographic distribution. Australia (Guglielmone and Robbins 2018).

Natural hosts. Reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma loculosum Neumann, 1907

Geographic distribution. Sub-Saharan Africa, Australia, several islands in the Indian and South Pacific Oceans (Guglielmone and Robbins 2018).

Natural hosts. Primarily birds and reptiles, occasionally bovids. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma longirostre (Koch, 1844)

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Primarily birds (immature stages) and New World porcupines (adults), but also a variety of mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma maculatum Koch, 1844

Geographic distribution. Southern USA, Central and South America (Cooley 1944; Guglielmone and Robbins 2018; Lado et al. 2018).

Natural hosts. Many reptiles, birds, and mammals, including humans (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia parkeri (tidewater spotted fever) (Sumner et al. 2007; Lee et al. 2019).

Amblyomma marmoreum Koch, 1844

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Immature stages primarily on birds and mammals. Adults on tortoises. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma mixtum Koch, 1844

Geographic distribution. Southern USA, Central and South America (Cooley 1944; Guglielmone and Robbins 2018).

Natural hosts. Variety of mammals, including humans, also birds, amphibians, reptiles (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia rickettsii (Rocky Mountain spotted fever) (Bermudez and Troyo 2018).

Amblyomma moreliae (Koch, 1867)

Geographic distribution. Australia (Roberts 1970).

Natural hosts. Reptiles. Zoonotic on humans (Roberts 1970).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma naponense (Packard, 1869)

Amblyomma mantiquirense Aragão, 1908

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Primarily mammals, including peccaries, carnivores, anteaters, marsupials, and rodents, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma neumanni Ribaga, 1902

Amblyomma furcula Dönitz, 1909

Geographic distribution. Argentina, Colombia (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including bovids, deer, carnivores, pigs, peccaries, and humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma nuttalli Dönitz, 1909

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Immature stages on a variety of mammals, birds, and reptiles. Adults primarily on tortoises. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Ambylomma oblongoguttatum Koch, 1844

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. A variety of mammals, including deer, rodents, carnivores, and marsupials, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma ovale Koch, 1844

Amblyomma fossum Neumann, 1899

Geographic distribution. Southern USA, Central and South America (Cooley 1944; Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily carnivores, rodents, tapirs, and humans. Occasionally marsupials, birds (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma pacae Aragão, 1911

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Primarily mammals, including rodents and marsupials, but also carnivores and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Ambylomma parkeri Fonseca & Aragão, 1951

Geographic distribution. Brazil (Guglielmone and Robbins 2018).

Natural hosts. Primarily rodents, also carnivores, marsupials, monkeys, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma parvum Aragão, 1908

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Wide variety of mammals, including humans, and birds (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma paulopunctatum Neumann, 1899

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily pigs, but also hippopotamuses, carnivores, and rodents, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma pecarium Dunn, 1933

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Peccaries, also deer. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma personatum Neumann, 1901

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Rhinoceroses, bovids. Zoonotic on humans(Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma postoculatum Neumann, 1899

Geographic distribution. Australia (Roberts 1970).

Natural hosts. Marsupials. Zoonotic on humans (Roberts 1970).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma pseudoconcolor Aragão, 1908

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Primarily armadillos, also marsupials and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma pseudoparvum Guglielmone et al., 1990

Geographic distribution. Argentina (Guglielmone and Robbins 2018).

Natural hosts. Caviomorph rodents. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma romitii Tonelli-Rondelli, 1939

Amblyomma tasquei Floch & Adonnenc, 1940

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Rodents, marsupials. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma rotundum Koch, 1844

Geographic distribution. Southern USA, Central and South America, Pacific Islands (Cooley 1944; Guglielmone and Robbins 2018).

Natural hosts. Reptiles and amphibians, occasionally birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma sabanerae Stoll, 1890

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Primarily reptiles, including tortoises, also amphibians, rodents, and marsupials. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma scalpturatum Neumann, 1906

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including tapirs, pigs, anteaters, peccaries, carnivores, and rodents. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma sculptum (Berlese, 1888)

Geographic distribution. South America (Martins et al. 2016; Guglielmone and Robbins 2018).

Natural hosts. Several mammals, including capybaras and humans, and birds (Osava et al. 2016; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment

Site in human host. Skin.

Vectored pathogens. Rickettsia rickettsii (Rocky Mountain Spotted Fever) (Ramírez-Hernández et al. 2020).

Amblyomma sparsum Neumann, 1899

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals, birds, and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma tapirellum Dunn, 1933

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Tapirs, peccaries, marsupials, rodents. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma tenellum Koch, 1844

Amblyomma imitator Kohls, 1958

Geographic distribution. Southern USA, Central America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including bovids, peccaries, horses, marsupials, carnivores, and rodents, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma testudinarum Koch, 1844

Geographic distribution. Central and Southeast Asia, Japan (Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals, including humans, birds, and reptiles (Guglielmone and Robbins 2018),

Route of infection. Exposure to larval, nymph, or adult ticks in the environment

Site in human host. Skin, ear (Nakao et al. 2017).

Vectored pathogens. Dabie bandavirus (severe fever with thrombocytopenia syndrome Virus, SFTSV) (Sato et al. 2021).

Amblyomma tholloni Neumann, 1899

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals, primarily elephants, and birds and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma tigrinum Koch, 1844

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Primarily carnivores, also rodents and ungulates. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma tonelliae Nava et al., 2014

Geographic distribution. South America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily bovids and equids. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia ricketsii (Rocky Mountain spotted fever) (Tarragona et al. 2016).

Amblyomma triguttatum Koch, 1844

Geographic distribution. Australia (Guglielmone and Robbins 2018).

Natural hosts. Primarily marsupials, also horses, bovids, carnivores, lagomorphs, rodents, humans, and reptiles (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma triste Koch, 1844

Geographic distribution. Southern USA, Central and South America (Cooley 1944; Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals, primarily bovids, deer, and carnivores, and birds. Zoonotic on humans (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia parkeri (Tidewater spotted fever) (Silveira et al. 2007).

Amblyomma tuberculatum Marx in Hubbard, 1894

Geographic distribution. Southeastern USA (Cooley 1944; Guglielmone and Robbins 2018).

Natural hosts. Tortoises. Zoonotic on humans (Cooley 1944; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Amblyomma variegatum (Fabricius, 1794)

Geographic distribution. Africa, Middle East, Caribbean (Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals, primarily bovids, also humans, birds, and reptiles (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia africae (African tick bite fever) (Dantas-Torres et al. 2012).

Amblyomma varium Koch, 1844

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily sloths, also marsupials, tapirs, carnivores, and rodents, also reptiles and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Genus Bothriocroton Keirans et al., 1994

Bothriocroton auruginans (Schülze, 1938)

Geographic distribution. Australia (Guglielmone and Robbins 2018).

Natural hosts. Marsupials, occasionally carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Bothriocroton hydrosauri (Denny, 1843)

Geographic distribution. Australia (Guglielmone and Robbins 2018).

Natural hosts. Reptiles, occasionally bovids. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Genus Dermacentor Koch, 1844

Dermacentor albipictus (Packard, 1869)

Ixodes nigrolineatus Packard, 1869

Geographic distribution. North and Central America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily cattle, deer, and horses. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Babesia duncani (babesiosis) (Swei et al. 2019).

Dermacentor andersoni Stiles, 1908

Dermacentor venustus Marx in Neumann 1897

Geographic distribution. Rocky Mountain region of North America (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including humans (Eisen 2007; Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment

Site in human host. Skin

Vectored pathogens. Rickettsia rickettsii (Rocky Mountain spotted fever), Francisella tularensis (tularemia), Colorado tick fever virus; also implicated in tick paralysis (Eisen 2007).

Dermacentor atrosignatus Neumann, 1906

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Pigs. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin, ear (Mariana et al. 2008).

Vectored pathogens. None.

Dermacentor auratus Supino, 1897

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Primarily pigs, but also a variety of other mammals, birds, and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin, ear (Ariyarathne et al. 2011).

Vectored pathogens. Rickettsia sibirica (Siberian tick typhus) (Dantas-Torres et al. 2012).

Dermacentor bellulus (Schülze, 1933)

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Immature stages primarily on rodents, also tree shrews, carnivores, lagomorphs, and birds. Adults are primarily on pigs, also carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor circumguttatus Neumann, 1897

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Primarily elephants, also duikers, pigs. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor compactus Neumann, 1901

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Primarily pigs, but also a variety of other mammals and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin, ear (Mariana et al. 2008).

Vectored pathogens. None.

Dermacentor hunteri Bishopp, 1912

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Primarily bovids, also deer, lagomorphs, and rodents. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor imitans Warburton, 1933

Geographic distribution. Central and South America (Guglielmone and Robbins 2018).

Natural hosts. Peccaries, deer. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor latus Cooley, 1937

Geographic distribution. Central America (Guglielmone and Robbins 2018).

Natural hosts. Primarily tapirs, also carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor limbooliati Apanaskevich & Apanaskevich, 2015

Geographic distribution. Malaysia, Vietnam (Apanaskevich and Apanaskevich 2015).

Natural hosts. Pigs. Zoonotic on humans (Apanaskevich and Apanaskevich 2015).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor marginatus (Sulzer, 1776)

Geographic distribution. Europe, western and central Asia, northern Africa (Rubel et al. 2016; Guglielmone and Robbins 2018).

Natural hosts. Many mammals, including humans, and birds (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia raoultii, Omsk hemorrhagic fever virus (Dantas-Torres et al. 2012).

Dermacentor nitens Neumann, 1897

Geographic distribution. Southern USA, Central and South America, Caribbean (Guglielmone and Robbins 2018).

Natural hosts. Horses, occasionally other mammals, reptiles, and amphibians. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor niveus Neumann, 1897

Geographic distribution. Central Asia, China, Russia (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including ungulates, rodents, lagomorphs, hedgehogs, and carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor nuttalli Olenev, 1929

Geographic distribution. Eastern Russia, Mongolia, China (Guglielmone and Robbins 2018).

Natural hosts. Immature stages on rodents, lagomorphs, hedgehogs. Adults primarily on ungulates and horses. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia sibirica (Siberian tick typhus), Francisella tularensis (tularemia), Crimean-Congo hemorrhagic fever virus (Gui et al. 2021; Kulakova et al. 2014).

Dermacentor occidentalis Marx in Curtice, 1892

Geographic distribution. Pacific coastal areas of Mexico and USA (Guglielmone and Robbins 2018).

Natural hosts. Several groups of mammals. Immature stages primarily on rodents and lagomorphs. Adults on cattle, deer, and humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia phlipii (Pacific Coast tick fever) (Padgett et al. 2016).

Dermacentor parumapertus Neumann, 1901

Geographic distribution. North America (Guglielmone and Robbins 2018).

Natural hosts. Lagomorphs, rodents, bovids, deer, carnivores, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor raskemensis Pomerantsev, 1946

Geographic distribution. Central and Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Bovids, carnivores, rodents, lagomorphs. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor reticulatus (Fabricius, 1794)

Dermacentor pictus Hermann, 1804

Geographic distribution. Europe and western Asia (Rubel et al. 2016; Guglielmone and Robbins 2018).

Natural hosts. Immature stages primarily on rodents, lagomorphs, hedgehogs, rarely birds and reptiles, and amphibians. Adults primarily on canids, also ungulates, and humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia slovaca (tick-borne lymphandenopathy, TIBOLA), Rickettsia raoultii, Omsk hemorrhagic fever virus (Földvári et al. 2016).

Dermacentor rhinocerinus (Denny, 1843)

Geographic distribution. Sub-Saharan Africa (Guglielmone and Robbins 2018).

Natural hosts. Primarily rhinoceroses, occasionally other mammals and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor silvarum Olenev, 1931

Dermacentor asiaticus Emel’yanova & Kozlovskaya, 1967

Geographic distribution. Eastern Russia, China, Mongolia (Guglielmone and Robbins 2018).

Natural hosts. Mammals, including bovids, deer, sheep, dogs, and humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia sibirica (Siberian tick typhus), Rickettsia raoultii (Cao et al. 2008).

Dermacentor similis Lado, Glon, et Klompen, 2021

Geographic distribution. North America, west of the Rocky Mountains (Lado et al. 2021).

Natural hosts. Several groups of mammals, including humans, and birds (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Rickettsia rickettsii (Rocky Mountain spotted fever), Francisella tularensis (tularemia); also implicated in tick paralysis (Wikswo et al. 2014; Moraru 2019; Mullen and Durden 2019).

Dermacentor steini (Schülze, 1933)

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Primarily pigs, but also a variety of other mammals and reptiles. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin, ear (Mariana et al. 2008).

Vectored pathogens. None.

Dermacentor tamokensis Apanaskevich & Apanaskevich, 2016

Geographic distribution. Southeast Asia (Apanaskevich and Apanaskevich 2016; Guglielmone and Robbins 2018).

Natural hosts. Pigs. Zoonotic on humans (Guglielmone and Robbins 2018)

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Dermacentor variabilis (Say, 1821)

Dermacentor electus Koch, 1844

Geographic distribution. Eastern North America (Guglielmone and Robbins 2018; Lado et al. 2021).

Natural hosts. Several groups of mammals, including humans, and birds. (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin, ear (Grady et al. 2011).

Vectored pathogens. Rickettsia rickettsii (Rocky Mountain spotted fever), Francisella tularensis (tularemia); also implicated in tick paralysis (Ammerman et al. 2004; Dergousoff and Chilton 2012; Moraru 2019; Mullen and Durden 2019).

Genus Haemaphysalis Koch, 1844

Haemaphysalis aculeata Lavarra, 1904

Geographic distribution. India, Sri Lanka (Guglielmone and Robbins 2018).

Natural hosts. Chevrotains, bovids, deer. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Kyasanur Forest Disease virus (Sharma et al. 2019).

Haemaphysalis anomala Warburton, 1913

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018),

Natural hosts. Immature stages on rodents and small birds. Adults on bovids, deer, carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Haemaphysalis aponommoides Warburton, 1913

Geographic distribution. China, India, Nepal (Guglielmone and Robbins 2018).

Natural hosts. Immature stages on rodents, shrews, birds. Adults on mammals, primarily bovids. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Haemaphysalis bancrofti Nuttall & Warburton, 1915

Geographic distribution. Australia, Indonesia, Papua New Guinea (Guglielmone and Robbins 2018).

Natural hosts. Primarily marsupials, but also a variety of other mammals and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Haemaphysalis birmaniae Supino, 1897

Geographic distribution. Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Bovids, deer, pigs, carnivores, and rodents. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. None.

Haemaphysalis bispinosa Neumann, 1897

Geographic distribution. Central and Southeast Asia (Guglielmone and Robbins 2018).

Natural hosts. Mammals, primarily bovids and carnivores, and birds. Zoonotic on humans (Guglielmone and Robbins 2018).

Route of infection. Exposure to larval, nymph, or adult ticks in the environment.

Site in human host. Skin.

Vectored pathogens. Kyasanur Forest disease virus (Sharma et al. 2019).

Haemaphysalis campanulata Warburton, 1908

Geographic distribution. Central and Southeast Asia, Japan (Guglielmone and Robbins 2018).

Natural hosts. Immature stages primarily on rodents. Adults on mammals, primarily carnivores. Zoonotic on humans (Guglielmone and Robbins 2018).