Spreading and Preventive Measures of Metagonimosis in the Amur Region

The purpose of the research is studying biology of Metagonimus yokogawai, metagonimosis seasonal dynamics in the Upper Amur River region, and influence of temperature factors on infection extensity.Materials and methods. The material for the research was collected in the Amur Region waters. The mollusks were studied for being infected with M. yokogawai by the A. S. Shatrov method: the water from petrie dishes was studied under an MBS-9 microscope for trematoda larvae after the mollusks were exposed in it for a day at water temperature of 18 оС. The mollusk Semisulcospiro cancellata liver was also studied for trematoda larvae using a compressor trichinelloscopy. 37 fish species were studied for being infected with metacercarias M. yokogawai by the G. A. Glazkov method. The infection of fish with metacercarias M. yokogawai and the prevalence of metacercarias were determined by infected scales using a microscope.Results and discussion. The infection of various fish species with metacercarias M. yokogawai in the study areas of the Amur Region is different and varies from 4 to 57%. The highest infection of definitive hosts in autumn leads to an increase in the concentration of parasite eggs in water reservoirs in such period, and to mass infection of molluscan intermediate hosts. The duration of M. yokogawai development in intermediate hosts is due to a low water temperature in the Upper Amur Region rivers in an autumn-winter-spring period. An infection peak of Carnivores with metagonimosis in the climate of the Upper Amur Region is observed once a year, in autumn. The fish caught in lowland rivers in autumn is the greatest danger for a human being.