Schistosomiasis is a widespread disease of man, other mammals and birds. It is due to infection by adult flukes which live in the blood stream and whose abundant eggs lodge in the capillaries of the bladder and intestine, producing local inflammation and not infrequently resulting in neoplasms. The eggs, discharged in urine or feces, hatch in water into free-swimming miracidia, which bore into fresh-water snails, pass through larval stages and emerge as fork-tailed free-swimming cercariae, which pierce the skin of the vertebrate host and find the blood stream, in which they complete the complicated life cycle.
All public health measures in prophylaxis and local eradication of the disease rest on the zoologic knowledge of the habits, life history, ecology and immunology of both the parasite and its intermediate host or hosts, for the fluke adapts itself to various mollusks.
This debilitating and potentially dangerous infection of man depends for its