Dientamoeba fragilis is a parasite that causes gastrointestinal problems. Despite its name, Dientamoeba fragilis is not an ameba but a flagellate. This protozoan parasite produces trophozoites; cysts have not been identified. Infection may be either symptomatic or asymptomatic.


What is Dientamoeba fragilis?

Dientamoeba fragilis is a parasite that lives in the large intestine of humans. 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. Loss of appetite and weight loss, nausea, and fatigue also are common. 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 samples for testing. Because the parasite is not always found in every stool sample, you might be asked to submit stool samples from more than one day. You might also be tested for pinworm eggs, which are commonly (but not always) found in persons infected with D. fragilis.

Is medication available to treat infection with Dientamoeba fragilis?

Yes. Safe and effective medications are available for D. fragilis infections.

How did I get infected with Dientamoeba fragilis?

This question is difficult to answer because we aren't sure how D. fragilis is spread. The parasite is fragile and probably cannot live very long in the environment. Infection might be spread by:

  • Accidentally swallowing pinworm eggs (which might protect this fragile parasite) or the eggs of another parasite.
  • Swallowing something, such as food or water, or touching to your mouth something contaminated with stool from someone infected with 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 have weak immune systems and those 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, changing diapers, and before preparing foods.
  • Teach children the importance of washing hands to prevent infection.



Causal Agent:

Despite its name, Dientamoeba fragilis is not an ameba but a flagellate. This protozoan parasite produces trophozoites; cysts have not been identified. Infection may be either   symptomatic or asymptomatic.


Life Cycle


The complete life cycle of this parasite has not yet been determined, but assumptions were made based on clinical data. To date, the cyst stage has not been identified in D. fragilis life cycle, and the trophozoite is the only stage found in stools of infected individuals. D. fragilis is probably transmitted by fecal-oral route.The and transmission via helminth eggs (e.g., Ascaris, Entamoeba spp has been postulated. Trophozoites of D. fragilis have characteristically one or  two nuclei and it is found in children complaining of intestinal (e.g.,   intermittent diarrhea, abdominal pain) and other symptoms (e.g., nausea,   anorexia, fatigue, malaise, poor weight gain).

Life cycle image and information courtesy of DPDx.

For more information view the source:Center for Disease Control