Metacercariae Opisthorchids in Commercial Carp Fish From the Lower and Middle Ob

This article shows the infection of commercial cyprinids from the Middle and Lower Ob with muscle trematodes that are dangerous to humans, collected in 2016, 2017 and 2018. From the point of view of human health, the study of carp fish infected with opistorchids is important. It is in the Ob – Irtysh basin that the world's largest opisthorchiasis is located. In the study of carp fish for infection with muscle trematodes, a compression method was used. Comparing the infection of carp fishes of different species with metacercariae opistorchids from different landscape-geographical zones, one can speak of the leading role of ide in maintaining the Ob - Irtysh center of opisthorchiasis.The role of the bream in maintaining the West Siberian focus of opisthorchiasis is gradually increasing due to the ever-growing herd of this fish. O. felineus and M. biliside infestation is most severe in Middle Ob, in the central taiga zone. In another subzone - the northern taiga (v. Hills) and the forest-tundra zone (v. Aksarka), the extensiveness of the O. felineus infection is either equal to 100% or approaches it. The intensity of infection in the ide from Middle Ob found maximum values. In other, more northern subzones, the intensity of infection with O. felineus metacercaria was significantly inferior to the infection of the Middle Ob’s ide. Based on the above, we can talk about the greatest infection of carp fish in Middle Ob. The center of the opisthorchiasis is situated exactly here.