There are approximately 43 species of trematodes which man acquires from eating improperly cooked fish, frogs, or crustaceans. A variety of wild and domestic mammals and birds also serve as the definitive host for the flukes. The organisms acquired from the ingestion of fish, parasitize the bile ducts and liver, all parts of the intestine as well as taking up residence in ectopic sites. The flukes acquired from ingesting crustacea parasitize the lungs and ectopic sites while those acquired from eating tadpoles or frogs inhabit the intestines of the host.