Amebiasis is an infection of the large intestines caused by Entamoeba histolytica, a single-celled parasite.

What is going on in the body?

The large intestine, or colon, is infected after amebic cysts are eaten. The parasite can then invade the colon, causing it to become inflamed.

What are the causes and risks of the infection?

Direct transmission of amebiasis occurs through contact with infected stool. The infection is also a sexually transmitted disease, particularly among male homosexuals. Fruits and vegetables can be contaminated when they are grown in soil fertilized by human stool, washed in polluted water, or prepared by someone who is infected.

Amebiasis is more common and more severe in subtropical and tropical areas. It occurs more often when living conditions are crowded, sanitation is poor, and nutrition is inadequate.