Viral zoonosis from the viewpoint of their epidemiological surveillance: tick-borne encephalitis as a model.

Tick-borne encephalitis (TBE) is a vector borne and, more rarely, a food (milk, milk products) borne disease of humans. For further characterization of the virus activity in natural foci of TBE more than 32,000 unengorged wild ticks were caught in low and high virus active foci in Germany (Mecklenburg-Western Pomerania, Saxony, Brandenburg, Thuringia, Bavaria, Baden-Württemberg, Saarland). The ticks were examined by RT-PCR and Southern blot hybridization as well as by classical virological methods. The dynamics of such natural foci of TBE in the last 35 years were discussed. Also nucleotide sequence data of parts of the virus genome (5'-non coding region) of 16 European and some Far East subtype strains were compared.