[The environmental conditions and predictors of formation of the bases for a combination of Diphyllobothrium dendriticum and Triaenophorus nodulosus foci in the flood-river ecosystem of the Angara River].

Investigations were conducted in the context of the landscape-biocenological concept. The formation of water-storage basins in the valley of the Angara River was shown to give rise to the transformation of the morphological structure and hydrological regimen of a landscape, which determined a change in some environmental conditions and factors of a combination of foci and the emergence of others. The morphological structure and hydrological regimen of a landscape, the species composition of ecosystems, the populations of hosts, and their biocenotic relations were transformed due to the direct anthropogenic impact on the landscape. There was an emergence of populations of pathogens, parasitic systems of foci, their functional and spatial structures and a formation of invasion foci as the ecosystems of water-storage basins were transformed. There changes were responsible for the formation of an anthropurgic focus of D. dendriticum and a two-host population-combined natural-anthropurgic focus of diphyllobothriasis - Triaenophorus infection. The susceptibility of hosts, the polyhostality of pathogens, and the mechanisms of their transmission are environmental factors that predetermine the formation of epizootic bases for a combination of foci and, being evolutionally formed and relatively strictly determined, have not undergone cardinal changes in the anthropologically transformed landscape.