any of a genus (Schistosoma) of flukes that live as parasites in the blood vessels of birds and mammals, including humans
See schistosome in American Heritage Dictionary 4
(shĭsˈtə-sōmˌ)
noun
Any of several chiefly tropical trematode worms of the genus Schistosoma, many of which are parasitic in the blood of humans and other mammals. Also called bilharzia, blood fluke.