FISH INVASION BY OPISTHORCHID FLUKES IN THE WATERPOTS OF THE CITY OF NOVOSIBIRSK

Abstract

The article presents data on the contamination of carp family fish with opisthorchid metacercariae and on the basis of this study, local foci of opisthorchidosis in reservoirs within the city of Novosibirsk were identified. Fishes for research were caught in the Nizhnyaya Yeltsovka and Inya rivers within the city of Novosibirsk. Fish studies were carried out by the compressor method. A total of 121 specimens of five species were investigated: ide, roach, dace, bream, verkhovka. Three types of opisthorchid metacercaria are found: Opisthorchis felineus, Metorchis bilis, and M. xanthosomus. The first two species have an epidemic significance, the latter – epizootic one. To assess the infection of fish, indicators of extensiveness and intensity of invasion, as well as an abundance index, were used.The results of studies showed that the level of infection of carp fish with larval forms of opisthorchids is 48.8% in total, while infection with metacercariae is: O. felineus 19.8%, M. bilis is 27.3% and M. hantomomus is 4.1%. In Lower Yeltsovka, the infection rate was 45.8%, in Ina – 55.3%. Earlier, our studies in the Lower Yeltsovka river detected mollusks-bitiniids, the first intermediate hosts of opisthorchids infected with their partins. Since the presence of the first and second intermediate, as well as definitive (human) hosts, is recorded at this point, the presence of a local focus in Lower Eletsovka can be considered indisputable. In Ina, the presence of a local focus is highly likely; for its final proof, it is necessary to detect opisthorchid-infected mollusks of this parthenites of Bithyniidae family.