Detection of Babesia spp. DNA in small mammals and ixodic ticks on the territory of north Ural, west Siberia and far east of Russia

Totally, 932 small mammals and 458 questing adult Ixodes persulcatus from Sverdlovsk and Novosibirsk regions and Khabarovsk Territory, as well as 128 Haemaphysalis japonica, 34 H. concinna and 29 Dermacentor silvarum from Khabarovsk Territory were examined for the presence of Babesia by nested PCR based on the 18S rRNA gene. Babesia microti DNA was found in samples of small mammals from all the studied regions--in 36.2% of samples from Sverdlovsk region, 5.3% of samples from Novosibirsk region, and 6.7% of samples from Khabarovsk Territory. The determined B. microti 18S rRNA gene sequences from Novosibirsk region (6 sequences) and from Khabarovsk Territory (10 sequences) were identical to each other and to the sequences of pathogenic for human B. microti US-type, while the determined B. microti 18S rRNA gene sequences from Sverdlovsk region (12 sequences) were identical to those of B. microti strain Munich. B. microti were found most frequently in samples of Myodes spp., they were found also in Microtus spp., Apodemus spp., Sorer spp., and Sicista betulinav. It was shown that one of 347 analyzed I. persulcatus from Novosibirsk region and one of 77 I. persulcatus from Khabarovsk Territory contained B. microti US-type DNA. One I. persulcatus from Novosibirsk region contained B. divergens DNA. In this work B. divergens was for the first time determined in I. persulcatus and B. microti in I. persulcatus in Asian part of Russia. Three different genetic variants of Babesia sensu stricto were found in three H. japonica from Khabarovsk Territory. The first genetic variant was closely related to Babesia sp. revealed in a feral raccoon in Japan (99.9% similarity on the basis of 18S rRNA gene sequences). Two others Babesia genetic variants were most similar to the ovine pathogen Babesia crassa (97.1-97.6% similarity on the basis of 18S rRNA gene sequences).