The amebas may be spread from person to person or through food or water.
People may have no symptoms or may have diarrhea, constipation, cramping abdominal pain, tenderness in the upper abdomen, and fever.
Doctors base the diagnosis on analysis of a stool sample and, if needed, other tests, such as colonoscopy or ultrasonography and blood tests.
People are given a drug that kills the amebas, followed by a drug that kills the dormant form (cysts) of the amebas in the large intestine.

(See also Overview of Parasitic Infections.)
Amebiasis tends to occur in areas where sanitation is inadequate. The parasite is present worldwide, but most infections occur in areas of Africa, the Indian subcontinent, and parts of Central and South America. In the United States, it is most likely to occur in immigrants and, less commonly, in people who have traveled to developing countries.
Worldwide each year, about 50 million people develop amebiasis, and as many as 100,000 of them die.
Entamoeba species exist in two forms:

An active parasite (trophozoite)
A dormant parasite (cyst)