Clinical Information

Amebiasis is an infection caused by the protozoan parasite, Entamoeba histolytica. The infection is acquired by ingestion of cysts in fecally contaminated food or water; excystation and infection occur in the large intestine. After excystation, trophozoites attach to the intestinal wall and excrete extracellular enzymes that enable invasion of the mucosa and spread to other organs, especially the liver and lung where abscesses may develop.

Amebiasis (or amebic dysentery) can cause bloody diarrhea accompanied by fever and prostration. White and red blood cells are found in the stool. Liver abscess can develop several weeks to months later producing hepatomegaly and fever.

Serology may be particularly useful in supporting the diagnosis of invasive disease with E histolytica, which is most commonly associated with amebic liver abscess. Serology should not be used to identify or diagnose amebic dysentery due to poor sensitivity in acute, noninvasive disease.