Freshwater gastropods as pathogens of natural focal invasions in the aquatic ecosystems of the Chernobyl exclusion zone

It has been established that 20 species (including two species complexes) of freshwater gastropods from 7 families live in water bodies on the territory of the PSRER, in which 51 species of trematodes from 21 families with a predominance of species of the Echinostomatidae family (10 species) parasitize at the parthenitis stage. The maximum number of trematode species was registered in the mollusks Lithoglyphus naticoides and Planorbarius corneus – 8 species of parasites with an infestation of 11.0 and 28.4 %, respectively. In the exclusion zone of the Chernobyl NPP, the circulation of natural focal helminthiasis caused by parasitization of trematodes Opisthorchiidae (Metorchis bilis, Pseudamphistomum truncatum, Opisthorchis felineus) identified in the studied animal species was established. For the mollusk Bithynia leachii, a high degree of infection (43.1 %) with the trematode O. felineus was noted.