[Tick-borne encephalitis in the Estonian SSR].

The foci of tick-borne encephalitis (TBE) of 2 types, differing in their morbidity rates, the character of their immunological structures, the species composition of carrier mites and their capacity for TBE virus carriership, have been shown to exist in Estonia. TBE morbidity is characterized by 4- to 5-year cycles, the overwhelming majority of TBE cases being registered in the area of the joint habitat of both species of mites. During the epidemic season 2 peaks of morbidity rise are registered, which corresponds to peaks in the number of mites in nature. Different epidemic importance of 2 species of carrier mites in TBE morbidity in Estonia has been shown.