Fast Facts

*More than 200 million people are infected with schistosomiasis worldwide.

*It is second to only malaria as the most devastating parasitic disease.

*Most human infections are caused by S. mansoru , S. haematobium, and S. japonicum.


The parasite lives in certain types of freshwater snails. Freshwater becomes contaminated when infected people urinate or defecate in it, transferring the eggs. If the appropriate snails are in the water, the worms multiply. The infection occurs when skin is contacted with contaminated water. When the worms penetrate the skin, they develop into adults in the blood vessels and mate; some eggs travel through the bladder and intestines.


Symptoms are caused by the body's reaction to the eggs, not the worms. One to two days after infection, an itchy rash will appear, One to two months after, fever, chills, cough. and muscle aches will occur. Children repeatedly infected with schistosomiasis develop anemia, malnutrition, and learning difficulties. Long term effects include damage to the liver, intestine, spleen, lungs, and bladder.

Common Areas

Schistosomiasis is found in Africa, South America, the Caribbean, the Middle East, Southern China, and parts of Southeast Asia, the Philippines, and Laos.

Measures of Control

Control efforts usually focus on:

*reducing the number of infections in people

*eliminating snails required for the worms' life cycle

*mass drug-treatment of communities

*targeted treatment of school-age children