Entamoeba histolytica can live in the large intestine (colon) without causing damage to the intestine. In some cases, it invades the colon wall, causing colitis, acute dysentery, or long-term (chronic) diarrhea. The infection can also spread through the blood to the liver. In rare cases, it can spread to the lungs, brain, or other organs.
This condition occurs worldwide. It is most common in tropical areas that have crowded living conditions and poor sanitation. Africa, Mexico, parts of South America, and India have major health problems due to this disease.
Entamoeba histolytica is spread through food or water contaminated with stools. This contamination is common when human waste is used as fertilizer. It can also be spread from person to person, particularly by contact with the mouth or rectal area of an infected person.
Risk factors for severe amebiasis include:
- Older or younger age
- Recent travel to a tropical region
- Use of corticosteroid medication to suppress the immune system
In the United States, amebiasis is most common among those who live in institutions or people who have traveled to an area where amebiasis is common.