Honcharov S. Helminthoses of the commercial fishes in the natural waters of Southern Ukraine (epizootology and parasite-host relationships)

The dissertational project gives the brand-new data about spreading of the zoonotic parasitic diseases – cryptocotylosis and eustrongylidosis of commercial fishes in the natural waters of the Black Sea and the Dnipro-Buuh estuary. The specific features of cryptocotyulosis among Gobiidae fishes and of eustrongylidosis among predatory fishes and roaches were found. Seasonal and age dynamics of the cryptocotyle and eustrongylide invasions of the commercial fishes in the natural waters of Southern Ukraine was observed. The localization and of the parasitic larvae from the Heterophyidae and Dioctophymatidae bloodline in the bodies of Gobiidae and predatory fishes was defined. Morphological features of the trematoda Cryptocotyle concava and Cryptocotyle jejuna, as well as of the nematode Eustrongylides еxcisus were explored. The referent indexes of the gastric juice amount and Ph among the laboratory rats were experimentally defined. The changes in the parasitic living environment and their potential ability to accommodate in the organisms of unspecific hosts were analyzed. The survival rate of the cryptocotyle metacercaria and the eustrongylide larvae in the researched ducklings and laboratory rats were calculated, analyzing the influence of the helminthoses’ agents on their organisms, as a resullt of the parasite-host relationships, with clinical, path-anatomic and histological changes in the organisms of the definitive hosts being taken as examples. Morphological and biological changes in the blood of the Gobiidae and predatory fishes were found in case of cryptocotylosis and eustrongylidosis. Association of the cryptocotyle and eustrongylide agents with other parasitic agents of commercial fishes was found. It also analyzed the influence of both biotic and abiotic factors on the primary site of the invasion being formed.