Study of natural foci of infections transmitted by ticks in the Republic of Tatarstan

The paper presents the history of tick-borne infections’ study, which was carried out at the Kazan Research Institute of Epidemiology and Microbiology, and an analysis of the current epidemiological situation of tick-borne infections in the Republic of Tatarstan. Tick-borne encephalitis was previously quite fully studied in the natural foci of the taiga zone of the USSR, but there was practically no information regarding the features of its distribution in the forest-steppe zone. The occurrence of a number of outbreaks of this disease in the territory of the Tatar ASSR and neighboring republics made research in this direction particularly relevant. Since 1955, the Kazan Research Institute of Epidemiology and Microbiology has begun work to identify and study natural foci of tick-borne encephalitis in the Middle Volga region. These studies have acquired the character of constant monitoring and are being systematically continued up to the present time. It was found that the main carriers of ixodid tick-borne borreliosis pathogens in Tatarstan are two types of ixodid ticks, the same as in viral tick-borne encephalitis. The similarity of the areas and basic patterns of the epidemiology of viral tick-borne encephalitis and borreliosis, as well as the possibility of the simultaneous circulation of the causative agents of these diseases (virus and borrelia) in the same ecosystem, has been revealed. Studies of the Kazan Research Institute of Epidemiology and Microbiology on the etiology, epidemiology and prevention of infections transmitted by ticks were carried out as part of long-term observations of the state of populations of various types of ixodid ticks in the physical and geographical regions of the Republic of Tatarstan, starting from the 50s of the XX century. This made it possible to trace changes in their spatial structure and assess their current epizootological significance. Landscape and epidemiological zoning of the republic's territories according to “tick-borne infections” has been carried out. Starting from 2012, new infections have been studied: monocytic ehrlichiosis and human granulocytic anaplasmosis.