[The functioning of foci of mixed tick-borne infections on Russian territory]

Based on the studies of behavioral variations in ixodes persulcatus ticks under the influence of their carried pathogens, the authors forward a hypothesis for that there is antagonism between Borrelia and tick-borne encephalitis virus in the vector. Experiments demonstrated that Borrelia-infected ticks had a lower viral sensitivity than did noninfected ticks. There was inhibited viral reproduction in the ticks with double infection. Evidence is presented for that the Borrelia-infected nymphal ticks display the specific behavioral and viral susceptible features that are physiologically peculiar to older Borrelia-free individuals. It is concluded that the prevalence of Borrelia in the populations of ticks in the foci of mixed infections is associated with their property to suppress viral reproduction in the Borrelia-infected ticks.