BILHARZIA

Disease caused by worms that parasitize people. Also called schistosomiasis.. Three main species of these trematode worms (flukes)--Schistosoma haematobium, S. japonicum, and S. mansoni—cause disease in humans. Larval forms of the parasite live in freshwater snails. The cercaria (form of the parasite) is liberated from the snail burrow into skin, transforms to the schistosomulum stage, and migrates to the urinary tract (S. haematobium), liver or intestine (S. japonicum, S.mansoni) where the adult worms develop. Eggs are shed into the urinary tract or the intestine and hatch to form miracidia (yet another form of the parasite) which then infect snails, completing the life cycle of the parasite.. Adult schistosome worms can seriously damage tissue. The name bilharzia comes from that of the shortlived German physician Theodor Bilharz (1825-1862).