Long-term dynamics of infection of small mammals with tularemia in the Stavropol region

The analysis of the infection of small mammals with tularemia on the territory of the Stavropol region for the period 1938-2020 was carried out. It is shown that the dynamics of the activity of the natural focus of tularemia is characterized by the change of intense epizooties and inter- epizootic periods. The method of autocorrelation analysis revealed the absence of periodicity in the manifestations of epizootic activity and the presence of cycles lasting 21 years, 12-13 years and 6-8 years. Epizooties are characterized by high intensity (10-30% of infected animals). The main mammalian species supporting the epizootic process were identified. A repeated change of the main carriers of the tularemia microbe during the studied period of time was established, while two species - the house mouse (Mus musculus) and the common vole (Microtus arvalis) are intensively involved in epizooties throughout the entire examination period. Basically, the species involved in epizooties belong to the first group of highly susceptible and highly sensitive to the mammalian tularemia microbe, at the same time, the results of the study revealed a high infection rate of the lesser white-toothed shrew (Crocidura suaveolens), which belongs to the second group of highly susceptible but insensitive animals. Probably, due to the intensification of human agricultural activity, there has been a change in the structure of the natural focus of tularemia, in particular, the species composition of the main carriers of infection, which led to a decrease in its activity.