For definition of Groups, see Preamble Evaluation .
Schistosomes are trematode worms that live in the bloodstream of human beings and animals.
The adults do not multiply in the body but live there for several years, producing eggs. Some eggs leave the body in the urine or faeces and hatch in water to liberate the miracidium larva, which infects certain types of freshwater snails. Within the snail, the parasites multiply asexually to produce free-swimming cercaria larvae, which infect people by skin penetration. The diagnosis of infection with Schistosoma is based on simple qualitative and quantitative examinations of faeces and urine. S. haematobium infection is identified on the basis of a history of haematuria, observation of gross haematuria, detection of haematuria by chemical reagent strips or detection of eggs in urine by microscopy.