Landscape epidemiology of hemorrhagic fever with renal syndrome in the Middle Volga Region

Human economic activity impairs the biocenotic relationships existing in the animal world and causes the formation of new ties that affect the epizootic and epidemiological situation of hemorrhagic fever with renal syndrome (HFRS). This accounts for the confinement of the natural foci of HFRS to the forest biotopes that preserve pathogen vectors and to the latter's absence in the human settlements surrounded by the transformed landscapes where the sources of the infection have disappeared from the composition of biocenoses. The European red-backed mouse (Clethrionomys) is the major reservoir in nature. The broad-leaved and mixed coniferous-broad-leaved forests of the Ural and Middle Volga Regions are the optimum area of this rodent. The Ulyanovsk Region has three types of landscapes: subtaiga, forest-steppe, and steppe zones. In the subtaiga zone, mortality is 5.4 and 10.7 times greater than that in the forest-steppe and steppe zones, respectively. Examining the epidemic process of HFRS has brought to light that its higher rates in the subtaiga area are due to a combination of social, natural, and biological factors. Success in combating the feral nidal infection cannot be expected without investigating the landscape features of its foci (a natural factor), without clarifying the forms of relationships of the pathogen with the host - the rodent and the environment (a biological factor), without taking into account the population groups that come into interaction with the pathogen population (a social factor).