Blood fluke

Blood fluke, also called schistosome, is a term in zoology and medicine for a parasitic flatworm. The adult flatworm lives in the blood vessels of birds and mammals and hence called blood fluke. It causes the disease called bilharzia in humans. The immature form of the blood fluke infests freshwater snails. Thus it needs two hosts to complete its lifecycle. It belongs to the genus Schistosoma, class Trematoda, and the sub class Digenea.