Siberian tick-borne typhus is one of three main tick-borne infections in Russia. The data on the
epidemiology of this infection testify not only to varying degrees of epidemic danger of regions, but also
on changes in the distribution of risk areas and identify new, epidemiologically significant foci.
The criteria for differentiation of focal areas on the risk of infection of the population with the causative
agent of Siberian tick-borne typhus have been developed. The ranking is based on the level of morbidity
for 1998 - 2016 on 16 endemic territories of the Russia. In accordance with the risk-oriented approach,
differentiation of focal areas was carried out with the allocation of epidemiological zones of low, medium,
higher than average and high risk of infection.
Pronounced heterogeneity of tick-borne rickettsiae circulating in the natural foci noted on molecular
biological, antigenic, immunogenic properties and virulence. Data on the main vectors, the transmission
mechanism, clinical manifestations, laboratory approaches to diagnosis and preventive therapy. Our
findings are important for the organization of epidemiological surveillance of this tick-borne infection.