Epidemiological Features of HFRS (Hemorrhagic Fever with Renal Syndrome) Outbreak in the Saratov Region in 2019

Objective of the study was to identify epidemiological peculiarities of HFRS outbreak in the territory of the Saratov Region in 2019 and to determine the key factors contributing to the intensity of epidemic process.

Materials and methods. Analyzed are the data on 2702 cases of HFRS registered in the territory of the Saratov Region in 2019, obtained from the Rospotrebnadzor Administration in the Saratov Region and Center of Hygiene and Epidemiology in the Saratov Region. The basic method of investigation was epidemiological one with application of advanced information technologies.

Results and discussion. Retrospective analysis of epidemic HFRS manifestations in the Saratov Region showed that HFRS outbreak of 2019 was the largest over the period of disease reporting, both by the number of cases (2702) and by the duration. Early onset of increase in the incidence (may) and allocation of the majority of cases to the territory of the natural park “Kumysnaya Polyana”(75 %) should be considered as characteristic features of the outbreak. We have conducted epidemiological zoning of the Saratov Region allowing for dividing the Region into four types of territories which differ by the level of risk of HFRS exposure (very high, high, medium, and low), as well as distinguishing the most hazardous in terms of HFRS infection territories of Saratov. The key factors affecting the surge in HFRS cases were high numbers of infected rodents during spring months of 2019 due to mild and extremely snowy winter of 2018–2019; reduction in forest engineering works aimed at turning the focal territory into aesthetic forestry. The change in the character of exploitation of 9 % of the natural park “Kumysnaya Polyana” resulted in the increase of population contacts with natural-focal complexes. Mass visits to natural focus during early spring period against the background of low alertness to risks of HFRS infection led to explosive growth of HFRS incidence.

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