Hard ticks (Acari, Ixodidae) of Croatia

Abstract The present paper is based on original and literature data. In Croatia the first studies on the occurrence of ixodid species were made about 80 years ago. The number of tick species recorded in Croatia considerably increased during the 1950s, 60s, 70s and 80s of the past century. A total of 21 species of hard tick belonging to 5 genera have been recorded in Croatia. Ixodes is the best represented genus, with seven species recorded. Haemaphysalis is represented by six species, followed by Rhipicephalus with four species. Dermacentor and Hyalomma are represented by two species each. The ticks were collected on 47 different host species. Eleven tick species were collected on Bos taurus and Ovis aries, followed by Capra hircus and Equus caballus with 8 species and Canis lupus familiaris with 6 species. On the remaining 42 host species one, two or three tick species were collected. The most widespread tick is Ixodes ricinus which was found on 25 different host species.


Introduction
Hard ticks (Acari: Ixodidae) are obligate hematophaguos ectoparasites and important vectors of viruses, bacteria and protozoa (Rijpkema et al. 1996, Polić et al. 2002, Duh et al. 2006, Hornok and Farkas 2009, Hubálek 2010. They are considered second only to mosquitoes as the most medically important group of arthropods (Jaenson and Jensen 2007). Approximately 10% of the currently known 896 tick species are vectors of pathogens from wild animals to humans (Milutinović and Radulović 2002). In Croatia, the first comprehensive studies on the occurrence of ixodid species were made about 80 years ago (Oswald, 1940(Oswald, , 1941a(Oswald, , 1941b. During the 1950s and 1960s, ticks in Croatia were studied from the ecological point of view . For that period, the data on tick fauna along the Adriatic Coast are numerous because Prof. Dr. Davor Mikačić, in several of his articles, presented the distribution and dynamics of hard ticks along the Adriatic coast from Pula to Dubrovnik. Furthermore, ecological studies of ticks were carried out on many islands in the Adriatic Sea during the 1970s, and 1980s, with special emphasis on the medical importance of ticks , Tovornik and Černy 1972, Tovornik and Šooš 1976, Tovornik and Brelih 1980, Tovornik and Vesenjak-Hirjan 1988, 1989, Vesenjak-Hirjan 1976, Vesenjak-Hirjan et al. 1977. In Europe, the number of papers on canine tick-borne diseases has progressively increased in the past few years (Földvári 2005). Climate change contributes significantly to the change of habitat conditions which may affect the geographic range expansion of some species of ticks and thus the spread of various pathogens (Lindgren et al. 2000). This indicates the importance of creating a list of the tick fauna in European countries, due to possible changes in the fauna of ticks and tick-borne pathogens. Another reason for creating a list of the Croatian tick fauna is that some tick species have been mistakenly referred to as new for the fauna or were omitted from the list of the Croatian tick fauna on the website of Fauna Europaea, although they had already been identified many years ago. Thus, the principal aim of this study is to summarize all available data on the tick fauna of Croatia. This work is based on literature findings and on the data obtained from faunistic research carried out during 2011 in the continental part of eastern Croatia (Slavonia and Baranja).

Material and methods
The following lists of species include all available literary records and new, still unpublished data. The samplings of ticks in Slavonia and Baranja were carried out during 2011 from the beginning of March to mid-September. Ticks were sampled by the flagging method, and were picked by hand from domestic animals and humans. The flagging method was used for tick sampling in two different vegetation types around the village of Mikleuš (YL 15). A 1 m 2 white flag was dragged over the vegetation for about 50 m at each locality. The first locality was in the mixed forests of durmast oak and hornbeam (as. Epimedio-Carpinetum betuli /Horvat 1938/ Borhidi 1963, whereas the second locality was in open biotopes on grassland. In the veterinary clinic in Đakovo (BR 92), ticks were sampled from dogs during vaccination or during normal veterinary examinations, while sampling from cats was performed in the village of Zmajevac (CR 37). Also, some ticks were sampled from humans in the village of Zmajevac. Identification was carried out using standard keys for European ticks (Hillyard 1996, Estrada-Peña et al. 2004. The names of the species were written according to Guglielmone et al. (2010). The nomenclature of hosts follows Fauna Europaea (http://www.faunaeur.org) and ITIS (Integrated Taxonomic Information System), (http://www.itis.usda.gov/index.html) for livestock.

Lacerta trilineata Bedriaga, 1886
Tick species: Haemaphysalis sulcata Sampling sites are identified by a running number referring to the map in Figure 1 and UTM grid 10×10 km given in the third column of

Results
The tick fauna of Croatia is now known to include 21 species. These species are classified into five genera: Dermacentor Koch, 1844, Haemaphysalis Koch, 1844, Hyalomma Koch, 1844, Rhipicephalus Koch, 1844, and Ixodes Latreille, 1795. The genera Dermacentor and Hyalomma are represented by a two species, followed by Rhipicephalus with four species, Haemaphysalis with six species, and Ixodes with seven species. While studying the territory of Slavonia and Baranja during 2011, a total of 1425 ticks were collected. All the collected ticks were classified into 5 species. The identified species were classified into the following genera: Dermacentor, Haemaphysalis and Ixodes. Ixodes ricinus made up 83.44% of the tick fauna in the researched area, while 16.56% were representatives of other species.

Survey of hard ticks recorded in Croatia
For every species are mentioned, sex, developmental stage ( ♂ male, ♀ female N = nymph, L = larva), sampling place, month or date, host and data source.  (Hubálek 2010) other pathogens infecting humans (Jaenson and Jensen 2007). Finally, new data were obtained on the geographical distribution of Ixodes ricinus, Dermacentor reticulatus, Haemaphysalis concinna and Ixodes hexagonus because the specimens of these species had not been found previously in eastern Croatia. Only Dermacentor marginatus was noted in 1955 in Baranja, in the territory of eastern Croatia ).