After many years of repeated infection, the parasite can damage the liver, intestines, lungs, or urinary bladder. Even without treatment, damage to these organs occurs only rarely in people such as travelers who have relatively short periods of exposure and who avoid reinfection. In the last few years, CDC has received reports of schistosomiasis in U.S. citizens who went on river rafting trips in Africa, tourists who swam in contaminated waters, and Peace Corps volunteers and other persons who lived and had fresh water contact in areas where schistosomiasis is a problem. Because there is no easy way to know if water is contaminated, avoid swimming or wading in fresh water when you are in countries where schistosomiasis is known to occur. Swimming in the ocean and in chlorinated swimming pools is generally thought to be safe.
Research is under way to develop a vaccine for humans, but none is available now.
See your health care provider. Be sure to give a complete description of the time, place, and length of your exposure to fresh water while in parts of the world where schistosomiasis occurs. You might be asked to undergo stool or urine tests to detect the eggs of the parasite. A blood test developed at CDC is also available. This test may be useful for making the diagnosis, particularly in U.S. travelers returning from areas where schistosomiasis occurs.