This condition is caused by a parasite found in feces. It may contaminate food or drinking water. It is most common in tropical and subtropical regions of the United States. To avoid infection, do not drink water from rivers and streams. When appropriate, drink bottled water or use filters on tap water. Cook food thoroughly.

Symptoms can include:

• stomach cramps
• watery diarrhea
• weight loss (which may be significant)
• weakness
• loss of appetite
• fever

Rehydration and nutritional support are key components of treatment. Antiparasitic drugs can treat the infection, but they may need to be taken for a long time to keep the parasite in check.