ABSTRACT
Amoebae belong to the subphylum Sarcodina, a group comprised mostly of freeliving organisms living in a wide variety of habitats. Symbiotic amoebae commonly found in the intestinal tract of humans and domestic animals belong to the genera Entamoeba, Endolimax and Iodamoeba (Fig. 1). Species infecting extraintestinal sites include members o f the genera Naegleria, Hartmannella and Acanthamoeba. The life cycle may involve just a motile, feeding trophozoite stage, or both trophozoite and cyst stages. In most members the trophozoite is amoeboid only, moving by means of pseudopodia. In some life cycles, both flagellate and amoeboid trophozoites are represented. Reproduction involves mitotic divisions of the nucleus followed by binary fission. Cysts may be ingested, or possibly even inhaled. Excystation generally occurs in the small intestine of the host.
