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Epidemiology & Risk Factors

Schistosomiasis is an important cause of disease in many parts of the world, most commonly in places with poor sanitation. School-age children who live in these areas are often most at risk because they tend to spend time swimming or bathing in water containing infectious cercariae.
If you live in, or travel to, areas where schistosomiasis is found and are exposed to contaminated freshwater, you are at risk.

Areas where human schistosomiasis is found include:

  • Schistosoma mansoni
    • distributed throughout Africa: There is risk of infection in freshwater in southern and sub-Saharan Africa–including the great lakes and rivers as well as smaller bodies of water. Transmission also occurs in the Nile River valley in Sudan and Egypt
    • South America: including Brazil, Suriname, Venezuela
    • Caribbean (risk is low): Dominican Republic, Guadeloupe, Martinique, and Saint Lucia.
  • S. haematobium
    • distributed throughout Africa: There is risk of infection in freshwater in southern and sub-Saharan Africa–including the great lakes and rivers as well as smaller bodies of water. Transmission also occurs in the Nile River valley in Egypt and the Mahgreb region of North Africa.
    • found in areas of the Middle East
  • S. japonicum
    • found in Indonesia and parts of China and Southeast Asia
  • S. mekongi
    • found in Cambodia and Laos
  • S. intercalatum
    • found in parts of Central and West Africa.
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