[Geographical variants in the immunological structure of the population in combined foci of tick-borne encephalitis and endemic rickettsiosis in the European part of the USSR].

The zonal study of the immunological structure of the population revealed an increase in the number of infective agents with which the population comes into contact in the southern regions. In the medial boreal forest zone contacts of low intensity only with tick-borne encephalitis virus were detected (the immune stratum was found to be 5.5%, 2,178 persons were examined); in the southern boreal forest zone the foci of tick-borne encephalitis actively manifested (the immune stratum reached 38.9%, 2,854 persons were examined), and Q fever was constantly detected (1.6%). In the forest-steppe zone the population was found to have contacts with the causative agent of tick-borne encephalitis (the immune stratum was found to be 13.3%, 2,056 persons were examined), Q fever (1.2%) and tick-borne rickettsiosis (1.1%).