a species of ameba that is the only distinct pathogen of the genus, the so-called “large race” of Entamoeba histolytica,
causing tropical or amebic dysentery in humans and also in dogs (humans are the reservoir for canine infections).
In humans, the organism may penetrate the epithelial tissues of the colon, causing ulceration (amebic dysentery);
in a small proportion of these cases, the organism may reach the liver by the portal bloodstream and produce abscesses (hepatic amebiasis);
in a fraction of these cases it may then spread to other organs, such as the lungs, brain, kidney, or skin and frequently be fatal.