Even brief exposures to contaminated water can result in infection. Travelers are advised not to bathe, swim or wade in fresh water in areas that are known to have this problem. Salt-water swimming is safe. Symptoms usually occur 2-3 weeks after exposure, but most acute infections are symptomatic. Acute symptoms may include fever, lack of appetite, abdominal pain, weakness, diarrhea, nausea and cough.
Chronic infection can cause disease of the lungs, liver, intestine and bladder.
Occassionally, people develop an itchy feeling immediately upon leaving the contaminated water. There is no practical way for the traveler to recognize infected water. It is best to just avoid fresh water in countries where Schistosomiasis exists. In such areas, heating water to 122F for 5 minutes or chlorinating water will make it safe for bathing. If water is left to stand for three days, the larvae will die in that time period and the water will be safe for washing.