Diversity of Borrelia burgdorferi sensu lato in natural foci of Novosibirsk region

Ixodes persulcatus ticks, wild small mammals, and infected people in Novosibirsk region of Russia were investigated to analyze the local distribution and diversity of Borrelia burgdorferi sensu lato. The molecular typing was based on the partial sequencing of the 16S rRNA gene and the 5S–23S rRNA intergenic spacer region. The analysis of our data revealed the presence of two Borrelia species, B. garinii and B. afzelii. B. garinii DNA was found much more often, namely in 74% of all PCR-positive human blood samples, in 72% of all samples from small mammals (including blood and tissues), and in 76% of Borrelia-positive unfed adult I. persulcatus. B. afzelii DNA was found in 21% of the PCR-positive human blood samples, in 20% of the PCR-positive samples from the small mammals (including blood and tissues) and in 19% of the PCR-positive ticks. Mixed infection with B. garinii and B. afzelii was observed in both clinical and environmental samples. Interestingly, four samples isolated from I. persulcatus were closely related to the relapsing fever species B. miyamotoi.