The life cycle of Entamoeba histolytica begins when humans ingest infective cysts via feces, fingers, food, fomites, and fleas. Then the cyst passes to the small intestine where excystation occurs and trophozoites multiply asexually by binary fission. The diagnostic stage is marked by resistant, infective cysts passed in feces.
Entamoeba histolytica (ameba). Infection occurs by ingestion of infective cysts from feces, hands, food, fomites, and flies. Excystation occurs in the small intestine; asexual multiplication and trophozoites in the large intestine. Infective cysts are released through the feces. Diagnosis by recovery/identification of cysts or trophozoites from feces or intestinal mucosa. Image from CDC via Pinterest, information from Medical Parasitology, A Self-Instructional Text.