Schistosomiasis are acute or chronic visceral parasitic diseases due to 5 species of trematode worms (schistosomes).
The 3 main species parasitizing humans are Schistosoma haematobium, Schistosoma japonicum and Schistosoma mansoni. The distribution area of Schistosoma mekongi and
Schistosoma intercalatum is more limited.
Humans are contaminated during bathing in infested freshwater schistosome larvae.
Infestation phases (transient localized itching at the transcutaneous penetration of larvae) and invasion (allergic manifestations and gastrointestinal symptoms during migration schistosomules) often go unnoticed.
The diagnosis is usually referred to the state phase.
Each species determines a clinical form: urogenital schistosomiasis due to S. haematobium, intestinal schistosomiasis due to S. mansoni, S. japonicum, S. mekongi and S. intercalatum.
The severity of the disease depends on the parasite load, an important factor for the occurrence of visceral involvement with potentially irreversible sequelae.
Children 5 to 15 years are the most vulnerable group: in this group the prevalence is highest and parasite load is maximum.
In endemic areas, an antiparasitic treatment should be given, even if there is a risk of re-infection, to reduce the risk of severe injury.