Study on the infection of taiga ticks with Borrelia in the territory of Novosibirsk Scientific Center SB PAS

In our study, Borrelia were revealed in the taiga ticks Ixodes persulcatus collected on vegetation by flagging, as well as in the ticks removed from the people who asked for help in the vaccination center located in the Novosibirsk Scientific Center of the Siberian Branch of Russian Academy of Science (NS SB RAS). By the isolation of Borrelia on BSK-H medum, the occurrence of B. garinii, B. afzelii, and B. miyamotoi was established in the territory of NSC. B. miyamotoi isolates were unstable and lost their ability to growth in later passages. DNA of the same three species of Borrelia was detected by PCR in the samples of ticks, both collected on vegetation by flagging and removed from humans. DNA of B. garinii was recorded most often; DNA of B. afzelii was less frequent; and the least number of positive samples was shown for B. miyamotoi. In the ticks collected on vegetation by flagging, DNA of B. garinii was found in 38.6%, B. afzelii in 9.9%, and B. miyamoboi in 3.9% of samples. In the ticks removed from people, number of positive samples was lesser; so, DNA of B. garinii was detected in 24.2%, B. afzelii in 6.9%, and B. miyamotoi in 5.6% of samples. Mixed infection with two Borrelia species was recorded, and DNA of B. mivamnotoi more often detected simultaneously with DNA of B. garinii.     

Genetic features of Borrelia miyamotoi transmitted by Ixodes persulcatus

The definition and molecular typing of Borrelia miyamotoi transmitted by the Ixodes persuccatus ticks was based on the partial sequencing of the 16S rRNA, p66, and glpQ genes. All the B. miyamotoi analyzed sequences of the 16S rRNA, glpQ, and p66 gene fragments from I. persulcatus were identical and had 99.9-100% similarity to corresponding genes of the B. miyamotoi strain FR64b isolated in Japan. The analyzed amino acid sequences revealed that the 66 protein B. miyamotoi in the site corresponding to the surface-exposed domain contained considerable difference from the Borrelia hermsii, the typical member tick-born relapsing fever, as from Borrelia lonestari transmitted by the Ixodes ticks.