On the cyclical manifestations of the dynamics of the incidence of hemorrhagic fever with renal syndrome in the Russian Federation

The hypothesis about a 49-year cycle in the incidence of HFRS in the Russian Federation in the period of 1957–2021 is substantiated. It has been established that the identified 49-year HFRS incidence cycle consists of 2 phases: a low incidence phase lasting 20 years (1967–1986) and a high incidence phase lasting approximately 29 years (1987–2016). It is of note that since 2017, there has been another phase of low incidence of HFRS in the Russian Federation, which, presumably, will continue until 2036. The prognostic indicator of the HFRS incidence for 2022 in the Russian Federation, obtained taking into account the current phase of low incidence, was 5.35?±?1.34 per 100 thousand population, with an actual level of 4.73 per 100 thousand population. A high degree of similarity in the dynamics of the HFRS incidence has been identified for the territory of the Republic of Bashkortostan (r = 0.87), the Republic of Tatarstan (r = 0.88) and the Russian Federation. It is outlined that the identified 20- and 29-year phases of the 49-year HFRS incidence cycle in the Russian Federation are generally determined by the epidemic activity of natural foci of the Puumala virus and coincide in duration with climate change waves in the European part of the Russian Federation. Keywords: сyclical nature of HFRS incidence, enzootic as regards HFRS territory, the Republic of Bashkortostan, epidemiological forecast, climate change.