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Small bowel (small intestine)

Infectious disorders

Entamoeba histolytica

Reviewer: Hanni Gulwani, M.D. (see Reviewers page)
Revised: 17 December 2012, last major update August 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.


● Dysentery causing protozoa that can also cause fulminant colitis; causes up to 100,000 deaths per year (Trop Biomed 2011;28:194)
● Increased incidence in homosexual men and AIDS patients


● Fecal-oral spread
● Amoeba invade colonic crypts, burrow into lamina propria, create flask shaped ulcer with broad base
● 40% invade portal vessels, embolize to liver and cause abscesses up to 10 cm
● May activate apoptosis in target cells (Trends Parasitol 2011;27:254)
● Rare abscesses in lung, heart, kidneys, brain

Life cycle

Micro images

Various images

Amoebic colitis, numerous trophozoites of amoeba are noted (courtesy of Dr. Hanni Gulwani)

Amoebic colitis, PAS stain (courtesy of Dr. Hanni Gulwani)

End of Small bowel (small intestine) > Infectious disorders > Entamoeba histolytica

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