[The morphogenesis of tick-borne encephalitis in light of the new data on virus replication].

The analysis of the RNA virus spread of tick encephalitis in the course of infection has been performed. The virus RNA is detectable first, (as early as one day after the infection) in the lymph nodes. Later it is retained in the cells of T-dependent areas. Viral RNA is also the first to be detected in the vascular structures and ventricular system of the brain. The correlation between the time of the viral RNA replication and specific initial damage in the lymphoid tissue and central nervous system is established. The question is raised on the role of the lymphocyte recirculation in the spread of the virus in the body.