[Genetic diversity of the tick-borne encephalitis virus in Ixodes persulcatus ticks in northeastern European Russia].

The genetic diversity of the tick-borne encephalitis virus (TBEV) in the PCR-positive Taiga ticks collected in the Republic of Komi in 2010 was evaluated. The analyses of nucleotide sequences of the 5'-NCR fragments of viral genome from ticks had shown that 13 isolates of TBEV from 16 sequencing variants were represented by the highly pathogenic Far Eastern genotype of the TBEV and only 3 isolates were identified as the Siberian genotype of TBEV. The nucleotide sequences of 5'-NCR of viral genome strongly varied variable in individual ticks. Variability for the A1 element has been observed in all the tested samples, and for elements C1, B2, CS B--in more than 50%. A2 element and ATG codon of the 5'-NCR remained completely conservative. Computer simulation of conformations of the 5'-NCR of TBEV genome demonstrated the possibility of significant changes of the spatial structure of the 5'-NCR of viral genome in individual taiga ticks. The obtained data confirm the hypothesis that the variability in the 5'-NCR of TBEV genome can be crucial for efficient replication of TBEV in different hosts.

[The role of birds in the maintenance of tick-borne infections in the Tomsk anthropurgic foci].

The role of birds in the focus of tick-borne infections was studied from 2006 to 2011. The frequency index of ticks carried by ground dwelling birds is about 49.7%. The index of their abundance is 3.8. The larvae of ticks have been found on birds in 43.8% of cases. Nymphs and adult ticks have been found in 39.9 and 16.3%, respectively. It was revealed that Ixodex pavlovskyi was transferred and dominated in the urban microfoci because of its ornithophily. The markers of infectious agents have been recorded in 42 of 60 bird species under study.