A genus of small flukes, usually less than 3 mm in length, common as parasites of dogs and cats in the Far East, N Siberia, and the Balkan States. Adult flukes of M. yokogawai occasionally infect the duodenum of man if undercooked fish (the intermediate host) is eaten. They may cause inflammation and some ulceration of the intestinal lining, which produces a mild diarrhea. Flukes can be easily removed with tetrachlorethylene.
A genus of flukes belonging to the family Heterophyidae.