Analysis of Epidemiological Situation on Crimean Hemorrhagic Fever in the Russian Federation in 2020 and Prognosis for 2021

The review presents an analysis of the epidemiological and epizootiological situation on Crimean hemorrhagic fever in the Russian Federation in 2020. During the stated period, 32 CHF cases were registered, which is the minimum indicator since the activation of the natural focus of CHF in 1999. The mortality rate was 3.1 %. The incidence was recorded in the Rostov, Astrakhan Regions, Stavropol Territory, the Republics of Dagestan and Kalmykia. A significant decrease in the incidence of CHF was noted in all entities of the Southern Federal District and the North-Caucasian Federal District. An imported from the Republic of Crimea case of CHF was detected in Moscow. The seasonality of morbidity, occupational, and age composition of CHF patients, modes of transmission, features of the clinical course of the disease in 2020 corresponded to the data of long-term observations. Epizootiological monitoring of the territory of the CHF natural focus showed that the abundance of Hyalomma marginatum adults and the percentage of Ixodidae tick pools positive for the presence of CCHF virus markers corresponded to the average long-term indicators at stationary observation points in 2020 , which indicates the persisting epizootiological disadvantage of the territory of the natural CHF focus in the Russian Federation. The persisting high numbers and infection rate of H. marginatum ticks can contribute to the development of an unfavorable epidemiological situation in the south of the country with a possible increase in the incidence of CHF in the Russian Federation in 2021.