Detection of Babesia DNA in small mammals and ixodid ticks in the North Urals, Western Siberia, and Far East of Russia

Abstract

A total 932 small mammals and 458 questing adult Ixodes persulcatus from Sverdlovsk, Novosibirsk regions and Khabarovsk Territory as well as 128 Haemaphysalis japonica, 34 H. concinna and 29 Dermacentor silvarum from Khabarovsk Territory was examined on the Babesia presence by nested PCR based on the 18S rRNA gene. Babesia microti DNA were found in samples from small mammals in all studied regions — in 36.2% of samples from Sverdlovsk region, in 5.3% of samples from Novosibirsk region and in 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 the sequence of B. microti strain Munich. B. microti were found most frequently in samples from Myodes spp., they were found also in Microtus spp., Apodemus spp., Sorex spp. and Sicista betulina. One from 347 analyzed I. persulcatus from Novosibirsk region and one from 77 I. persulcatus from Khabarovsk Territory were shown to contain B. microti US-type DNA. One I. persulcatus from Novosibirsk region have contained B. divergens DNA. This is the first determination of B. divergens in I. persulcatus and the first determination of B. microti in I. persulcatus in Asian part of Russia. Three novel genetic variants of Babesia sensu stricto were revealed in three H. japonica from Khabarovsk Territory. One novel Babesia 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 Babesia crassa (97.1–97.6% similarity); they clustered together with ruminant pathogens B. crassa and Babesia major.