a helminthic disease that affects the liver and pancreas. Opisthorchiasis is prevalent in Western Siberia and in the region of the Dnieper. The causative agent, the Siberian liver fluke (Opisthorchis felineus), infests the liver, gallbladder, and pancreas of man, cats, and dogs. The main sources of the disease are infected persons and animals, whose feces carry the parasite’s eggs to water. The eggs are swallowed by snails, in which the larvae of the flukes reproduce. Finally, the flukes emerge into the water as cercariae that encyst on cyprinid fish, such as the ide, dace, and roach. Man becomes infected by eating raw or insufficiently fried or salted fish.

The early symptoms of opisthorchiasis are fever, hives, and aching muscles and joints. Pain subsequently develops in the right hypochondriac and epigastric regions. The liver and gallbladder are frequently enlarged. Chloxylum is used in the treatment of the disease. Opisthorchiasis is prevented by eating only well-cooked, well-fried, or thoroughly salted fish. Pollution of bodies of water by fecal matter can also be controlled.

Animals contract opisthorchiasis by eating raw, frozen, or unsalted fish that are infested with metacercaria. Severe infestation exhausts an animal and causes its fur to ruffle. Frequently, the sick animal experiences an increase in appetite. The diagnosis is based on clinical and epizootiological data and on the results of laboratory tests. Opisthorchiasis in animals is treated with hexachloroparaxylol and other anthelmintics. It is prevented by not feeding animals raw fish in regions where opisthorchiasis is prevalent.