ERCARIAE OPISTHORCHIS FELINEUS AND METORCHIS BILIS FROM FIRST INTERMEDIATE HOSTS FOR THE FIRST TIME IN BASIN OF CHANY LAKE (NOVOSIBIRSK REGION, RUSSIA) IS FOUND

Objective of research: to perform the analysis of long-term (15 annum) dynamics of Bithyniidae snails infected by trematode parthenites from the Chany Lake, the biggest lake in the south of Western SiberiaMaterials and methods: The Bithyniidae snails examined in the lake-river systemsChanyLake in 1994-2013 (in the middle reaches and in the estuary of theKargatRiver) and in theZolotyeRossypiBay and theMalyeChanyLake. The Bithyniidae snails were collected from May to September (twice in any ten days) by hand from 4–6 plots of0.25 m2 at a depth of 0.1–0.7 m. In total, 8,316Bithynia troscheli (Paasch, 1842) and 766 В. tentaculata (L., 1758) were examined. Identification of parthenitae trematode was based on observation when mature cercariae were capable of leaving the shell of the host snail on their own.Results and discussion: In Bithyniidae snails, we found parthenites from trematodes from 12 families Cyathocotylidae Mühling, 1898 Poche, 1925; Prosthоgonimidae Luhe, 1909; Pleurogenetidae Looss, 1898; Lecithodendriidae Odhner, 1911; Microphallidae (Ward, 1901) Travassos, 1920; Plagiorchiidae Lühe, 1901 Echinostomatidae (Looss 1899) Dietz, 1909 Odhner 1910); Psilostomidae (Looss 1900) Odhner 1913; Notocotylidae Luhe, 1909; Monorchiidae Odhner, 1911; Cyclocoelidae Kossack, 1911 и Opisthorchidae (Lass, 1899) Braun, 1901. The prevalence of bithyniid snails infected by trematode parthenites varied from 1,6% to 24,1% in different years.The double infection by trematode parthenites was found in 0,96% bithyniid snails from estuary of theKargatRiver; 4,45% in theMalyeChanyLake, and 26,6%, in theZolotyeRossypiBay. The cercariae of Opisthorchidae family in four annum of the fifteen detected. The prevalence of bithyniid snails infected by trematode parthenites from Opisthorchis felineus (Rivolta, 1884) and Metorchis bilis (Braun, 1890) was observed inChanyLakesystems for the first time. Both species (O. felineus and M. bilis) of trematodes have danger to human health and causes very dangerous disease, opisthorchiasis and metorchiasis.