Infection with Hepatozoon in the small Croatian rodents Apodemus sylvaticus, Apodemus flavicolis, Apodemus agrarius and Clethrionomys glareolus

Wild rodents play an important role in nature as reservoir hosts for many pathogens, including some that can be transmitted to other animals. Hepatozoon sp. parasitizes many mammals, especially rodents, and its infections are dependent on zoonotic cycles that also involve arthropode vectors. High prevalence of Hepatozoon sp. in small wild rodents has been reported in Northern and Central America, West Africa and Europe. Due to previously non-existing data on hepatozoonosis in wild animals in Croatia, we investigated 120 small wild rodents, including 48 woodmice Apodemus sylvaticus, 37 yellow-necked mice Apodemus flavicolis, 2 striped field mice Apodemus agrarius and 33 bank voles Clethrionomys glareolus. DNA was isolated from spleen tissue and the screening PCR on the 666 bp fragment of 18S rRNA revealed 35 (29%) hepatozoon-positive rodents: 25 (75, 8%) C. glareolus, 7 (14, 6%) A. sylvaticus, 3 (8, 1%) A. flavicolis and no A. agrarius. Positive samples were confirmed by partial sequencing of 18S rRNA gene. Sequences were blasted against Hepatozoon sp. 18S SSU rRNA available at GenBank. The alignments have revealed 33 H. sp. sequences identical to isolates AY600625 and AY600626 from Spanish bank voles and 2 sequences with the highest homology to H. ayorgbor isolate EF157822 from phyton. Obtained results are in agreement with investigations in other European countries, which showed that Hepatozoon infections are especially common in the bank voles.