[Effect of the properties of tick-borne encephalitis virus strains ciruclating in nature on the immunity of the Priamurian population].

Strains of tick-borne encephalitis virus isolated from I. persulcatus ticks collected in various landscape zones of Priamurie differ in their invasiveness and hemagglutinating activity. A relationship between these properties of tick-borne encephalitis virus strains and the percentage of immune subjects in the population has been established. The coefficient of the epidemic danger of a landscape zone is described which includes the index of probability of infection and characteristics of the index of strain invasiveness and permits prognosis of the nature of the epidemic process in the area.