[The Aĭna/1448 serotype of the tick-borne encephalitis virus].

The antigenic structure of 48 tick-borne encephalitis virus (TBE) strains isolated in the Irkutsk region and the Buryat ASSR in 1960-1981 was studied. Antigenic analysis was performed by the agar gel diffusion-precipitation test using adsorption of the immune sera. A new group of 31 TBE virus strains was found to belong to the Aina/1448 antigenic type. Close ecological relationship between this serotype and Muridae was found. Ix. persulcatus ticks are vectors of 2 TBE virus serotypes, Aina/1448 and eastern serotype. Data on combined circulation of these 2 serotypes of TBE virus in the Irkutsk region and the Buryat ASSR were obtained, the Aina/1448 serotype definitely dominating in 3 areas of the Irkutsk region. The areas of circulation of the Aina/1448 serotype strains are associated with forest and forest-steppe landscapes disturbed by human economic activity.