STUDY OF MOLLUSCS IN BIOTOPES ON PASTURES CONTAMINATED BY FASCIOLA HEPATICA

The mollusk Lymnaea truncatula is an intermediate host of Fasciola hepatica. However, the involvement of other mollusk species (L. stagnalis, Galba palustris, etc.) in the F. hepatica development cycle might take place. In this connection, we have studied the spread of molluscs of these species in areas contaminated by Fasciola hepatica. The research purpose was to study the infection of molluscs by Fasciola larvae in the habitats (biotopes) on pastures contaminated by trematodiasis in the Bryansk Region. We determined the population density of molluscs and their species on the pastures, and the infection dynamics of parthenita stages of F. hepatica in molluscs. The study was performed on 3 pastures of 12 to 27 hectares from April to October 2021. The following molluscs were examined: 10 to 93 specimens of the snail L. truncatula, 11 to 24 specimens of the great pond snail L. stagnalis, and 12 to 42 specimens of the aquatic snail L. palustris. Molluscs were examined for infection with Fasciola larvae by the compression method every month during the grazing period (April-October). As a result of the study, the snail L. truncatula was only found to be infected by larval stages of Fasciola. The remaining lymnaeids were free from this trematode invasion. The snail L. truncatula was more infected with Fasciola in September. The Fasciola larvae in the snail were observed in May, August and September with the infection rate of 2.3%, 3.5% and 4.3%, respectively.