[Characteristics of the spatial and biocenotic structure of the Transural steppe plague reservoir].

In the trans-Uralian steppe focus, the manifestations of plague are characterized by a cyclical pattern. Nine epizooties, each lasting 1 to 16 years, were identified in this region in 1913 to 1992. The interepizootic periods varied from 1-3 to 17 years. Plague was most commonly manifested in the south of the focus (8 cycles) in the mixed habitats of small sousliks, giant and minor day jirds. Since the 1960s when there were steady-state habitats of giant day jirds in this region, the interepizootic periods have reduced to 4 years. In the north of the focus, plague was much less frequently registered (4 cycles) in the habitats of minor day jirds and the maximum interepizootic period was 36 years. The topography of epizooties shows an irregular pattern of their spatial arrangement and a pronounced confinement to specific sites of the area. Differentiation of epizootic sectors by the incidence of recurrent plague and its duration makes it possible to identify the "cores" of epizooties at these sites.