snail fever --> schistosomiasis
disease (bilharzia) caused by digenetic trematode worms of the genus schistosoma, the adults of which live in the urinary or mesenteric blood vessels. Eggs shed by the female worms pass to the outside in the urine or faeces, but many also lodge in and obstruct the blood flow in the liver. Eosinophils seem to be particularly important in the killing of the invasive larval stage (schistosomulum). Evasion of the host's immune response by adult schistosomes seems to involve the acquisition of a coat of host cell surface material by the parasite.