Helminths in fish from lake and river systems of the Upper Kolyma Highlands that have medical and veterinary significance

The purpose of the research is to extend information across the distribution of zooanthroponotic helminth infections transmitted through freshwater fish in the Magadan Region.Materials and methods. The study area is located in the Upper Kolyma basin on the Magadan Region and the Republic of Sakha (Yakutia) border. The Omulevsky Park is also located here, one of the clusters of the Chersky National Park named after A. V. Andreev. The existing lake and river systems (Darpir, Momontai, Malyk, Urultun and Ui) are inhabited by 7 fish species: Arctic char (Salvelinus alpinus), east-Siberian grayling (Thymallus arcticus pallasi), round fish (Prosopium cylindraceum), Siberian sucker (Catostomus catostomus rostratus), burbot (Lota lota leptura), common minnow (Phoxinus phoxinus) and sculpin from the Kolyma (Cottus kolymensis). 685 specimens of fish were undergone parasitological survey using established procedures. The found helminths were fixed in 70% ethanol and clarified in glycerol.Results and discussion. In the study of the fish helminth fauna in the lake and river systems of the Upper Kolyma Highlands, three helminth species that posed a danger to humans and animals were identified, Dibothriocephalus dendriticus, D. ditremus (Diphyllobothriidae) and Eustrongylides excisus (Dioctophymatidae). Information was provided on fish infection with these parasites in the lake and river systems, and their distribution in the Magadan Region, and a brief description of these types of helminths was given. In domestic scientific and methodological publications, the problem of eustrongylidiasis as a zooanthroponotic disease is not sufficiently covered, therefore, emphasis is placed on nematodes of the genus Eustrongylides. The research results may attract the attention of sanitary and veterinary service specialists to this issue, especially given the creation of a national park in the Magadan Region. Data on the freshwater fish infection with Diphyllobothriidae in the Upper Kolyma Lake and river systems expand the diphyllobothriasis nosoarea in the Magadan Region and allows the Susumansky District to be included in its boundaries.