CURRENT DATA ON THE SPECIES DIVERSITY OF TREMATODE METACERCARIA IN CYPRINIDS IN THE LIPETSK REGION

Cyprinids as the second intermediate host are a source of infection of the definitive host with zoonotic trematode infections. Currently in some regions of European Russia, opisthorchiasis is constantly recorded in humans. This relates to the Lipetsk Region, where the species diversity and distribution of opisthorchides, ecological biological and epizootological aspects of the circulation of opisthorchidosis remain unstudied. The materials were collected in 2021-2022 in the south-eastern part of the Lipetsk Region on the Usman River. We studied 179 specimens of 4 Cyprinid species: the roach (97 specimens), the bleak (41 specimens), the silver bream (21 specimens) and the rudd (20 specimens). The highest infection rates were observed for opisthorchide metacercariae (Opisthorchis felineus, Pseudamphistomum truncatum, Metorchis bilis and Metorchis xanthosomus) with the infection prevalence (IP) of 78.2%; the second position was occupied by Posthodiplostomum cuticola with the IP 63.7%; they were followed by Paracoenogonimus ovatus with similar parameters with the IP 21.8% and Metorchis xanthosomus with the IP 19.6%. According to the results of our research, 6 species of trematode metacercariae including 3 opisthorchide species (O. felineus, P. truncatum, M. bilis) of epidemiological significance were recorded for the first time in cyprinid fish in the Lipetsk Region. For all metacercariae species, the current parameters of infection in cyprinids were revealed.