Ixodes ticks as carriers of human and animal babesiosis agents in the Baikal region

Background . Piroplasmosis (babesiosis and theileriosis) is a group of natural focal infectious diseases of humans and animals caused by intraerythrocytic parasites transmitted predominantly by ixodid ticks. In the Baikal region, despite the widespread foci of babesiosis and theileriosis, the data about these pathogen vectors is fragmentary. The aim . To identify human and animal babesiosis vectors, study various Babesia spp. tropism to ixodid ticks common in the Baikal region. Materials and methods . A total of 3,239 specimens of I. persulcatus, 1,795 specimens of D. nuttalli and 729 specimens of H. сoncinna ticks collected in natural habitats of the Baikal region from 19 districts of the Irkutsk region and six districts of the Republic of Buryatia, as well as 5 specimens of D. nuttalli ticks removed from horses were examined for the presence of Babesia spp./Theileria spp. DNA. For detection and typing of Babesia and Theileria, a nested PCR with genus- and species-specific primers corresponding to 18S rRNA gene region was used. Selective sequencing of samples was performed to study the genetic diversity of the identified pathogens. Results . Babesia spp. DNA was detected in three species of ixodid ticks in Irkutsk region and in one species in the Republic of Buryatia. In I. persulcatus ticks B. microti US-type, B. venatorum, B. crassa-like and a unique Babesia sp. Irk-Ip655 were found. DNAs of B. crassa-like, B. motasi-like and Babesia spp. were detected in H. concinna ticks. DNAs of Babesia spp. And T. equi were found in D. nuttalli ticks. Conclusion . Vectors of both human and animal babesiosis pathogens were detected in the Baikal region. Tropism of B. microti US-type and B. venatorum in relation to I. persulcatus ticks was established. The establishment of specific relations between other species of Babesia and Theileria and vector ticks in the Baikal region will be continued.