Entamoeba dispar

Amebiasis ajfects 10% of the world s population. In the U.S., amebiasis is usually seen in those living in crowded, unsanitary conditions. Entamoeba dispar accounts for 90% of human infections and E. histolytica/or only 10%, but only E. histolytica causes human disease. Humans are the only known hosts for these protozoa, which are transmitted almost exclusively by the fecal-oral route. E. histolytica cysts ingested from contaminated food or water transform into trophozoites that reside in the large intestine. Many individuals infected with E. histolytica are asymptomatic but excrete infectious cysts, making them a source for further infections. In others, E. histolytica trophozoites invade the colonic mucosa with resulting colitis and bloody diarrhea (amebic dysentery). Rarely, E. histolytica trophozoites invade through the colonic mucosa and reach the liver via the portal circulation, where they establish an amebic liver abscess. 

Because of its worldwide distribution and serious gastrointestinal manifestations, amebiasis is one of the most important parasitic diseases of humans. " "" The major causative organism in amebiasis is Entamoeba histolytica, which inhabits the colon and must be differentiated from the E. dispar, which is associated with an asymptomatic carrier state and is considered nonpathogenic. Although E. histolytica and E. dispar are indistinguishable morphologically, recent research... 

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