Amebas are unicellular organisms common in the environment: many are parasites of vertebrates and invertebrates. Relatively few species inhabit the human intestine and only Entamoebahistolytica is identified as a human intestinal pathogen. A second pathogen of the human colon is Dientamoeba fragilis, which looks like an ameba under the light microscope, and was classified as a true ameba for many years, but which is now identified as a flagellate.
Copyright © 1996, The University of Texas Medical Branch at Galveston.