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Entamoeba histolytica. Beth Wozney. Geographic Distribution. Worldwide! Higher rates: Tropical areas. Hosts. Definitive Humans Intermediate None are necessary Reservoir Dogs Pigs Monkeys Humans (asymptomatic). Causes Amebic Dysentery. Symptoms: Abdominal pain Weight loss
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Entamoebahistolytica Beth Wozney
Geographic Distribution • Worldwide! • Higher rates: • Tropical areas
Hosts • Definitive • Humans • Intermediate • None are necessary • Reservoir • Dogs • Pigs • Monkeys • Humans (asymptomatic)
Causes Amebic Dysentery • Symptoms: • Abdominal pain • Weight loss • Bloody, mucous diarrhea • Intestinal lesions • Can invade liver, lungs, and brain • May cause death • 40,000-100,000 deaths per year
Entamoebahistolytica • http://animal.discovery.com/videos/monsters-inside-me-entamoeba-histolytica.html
Life Cycle Continued… • Human ingests cysts from fecally contaminated food or water • In the large intestine, trophozoites undergo binary fission and multiply. • Cysts and trophozoites are passed in the feces.
Pathogenesis • Vary from asymptomatic to severe • Amoebic dysentery: trophozoites invade the intestinal wall, leading to amoebic ulcer formations. • Diarrhea with blood and mucus • Liver abcesses • Spread to lungs and brain • Death
Diagnosis • Direct Fecal Smear and staining: ingested red blood cell with distinctive nucleus • Cysts: Cigar-shaped bodies, 4 nuclei, chromatoid bodies • Enzyme Immunoassay (EIA) • Indirect Hemagglutination • Antigen Detection • PCR: for species identification
Treatment • Metronidazole • Tinidazole • Best method: Prevention! • Filter drinking water in endemic areas • Wash fruits and vegetables • Wash your hands
Entamoeba coli • Common • Similar life cycle (Ingested cysts) • Nonpathogenic • Must be differentiated from E. histolytica
Some True/False… • Entamoebahistolytica is only found in Africa and South America. • Entamoebahistolytica is the only pathogenic species of all the amebae. • Trophozoites and cysts can both be found in the stools of infected patients. • An intermediate host is necessary for the transmission of Entamoebahistolytica.