Dientamoeba fragilis FAQs

What is Dientamoeba fragilis?

Dientamoeba fragilis is a parasite that lives in the large intestine of people. Infection is common worldwide, including in the United States.

What are the symptoms of infection with Dientamoeba fragilis?

Many infected people do not have any symptoms. The most common symptoms are diarrhea and abdominal pain. Symptoms also can include loss of appetite, weight loss, nausea, and fatigue. The infection does not spread from the intestine to other parts of the body.

What should I do if I think I might be infected?

See your health care provider.

How is infection with Dientamoeba fragilis diagnosed?

Your health care provider will ask you to provide stool specimens for testing. Because the parasite is not always found in every specimen, you might be asked to submit stool from more than one day. You might also be tested for pinworm eggs, which sometimes are found in people who are infected with D. fragilis.

Is medication available to treat infection with Dientamoeba fragilis?

Yes. Safe and effective medications are available to treat D. fragilis infection.

How do people get infected with Dientamoeba fragilis?

This question is difficult to answer because we aren’t sure how D. fragilis is spread. Most likely, people get infected by accidentally swallowing the parasite; this is called fecal-oral transmission. The parasite is fragile; it probably cannot live very long in the environment (after it is passed in feces) or in stomach acid (after it is swallowed). An unproven possibility is that pinworm eggs (or the eggs of another parasite) help protect and spread D. fragilis.

Who is at greatest risk for infection?

Anyone can become infected with this parasite. However, the risk for infection might be higher for people who live in or travel to settings with poor sanitary conditions.

How can I prevent Dientamoeba fragilis infection?

• Wash your hands with soap and warm water after using the toilet, after changing diapers, and before preparing or eating food.
• Teach children the importance of washing hands to prevent infection.

More on: Handwashing

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This information is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the parasites described above or think that you may have a parasitic infection, consult a health care provider.