[Experience with using the indirect hemagglutination reaction in studying natural foci of tick-borne encephalitis].

Using the indirect hemagglutination test, tick-borne encephalitis (TBE) virus could be detected in the nutrient medium of the infected cell cultures, in brain suspensions of the infected suckling mice and in most specimens of suspensions of Ixodid ticks containing active virus. Positive results were obtained only with erythrocyte immunoglobulin diagnostic preparation to TBE virus but not with the diagnostic preparation for Omsk hemorrhagic fever. In the indirect hemagglutination inhibition test sera from human patients similarly inhibited antigens of tick-borne encephalitis and Omsk hemorrhagic fever.