Life cycle of Entamoeba histolytica

Entamoeba histolytica exists in two forms: cysts that can survive outside the body and labile but invasive trophozoites that do not persist outside the body. Cysts, ingested through feces-contaminated food or water, pass into the lumen of the intestine, where the trophozoites are liberated. The trophozoites multiply, and they either invade and ulcerate the mucosa of the large intestine or simply feed on intestinal bacteria. [Note: One strategy for treating luminal amebiasis is to add antibiotics, such as tetracycline, to the treatment regimen, resulting in a reduction in intestinal flora, the ameba’s major food source.] The trophozoites within the intestine are slowly carried toward the rectum, where they return to the cyst form and are excreted in fece Large numbers of trophozoites within the colon wall can also lead to systemic invasion.