EntomoebahistolyticaCO - Amebiasis (caused by Entomoeba...

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Amebiasis (caused by Entomoeba histolytica - course objective) Alaina Maxwell (I tried to highlight the important parts.) highest prevalence of amebiasis is in developing countries with inadequate barriers between human feces and food/water supplies primarily spread via fecal-oral route and sexual transmission is also possible most cases are asymptomatic, but dysentery and invasive extraintestinal disease can occur amebic liver abscess is the most common manifestation can also involve other organs Pathophysiology E histolytica is a pseudopod-forming, nonflagellated protozoal parasite that causes proteolysis and tissue lysis (hence its name) and can induce host-cell apoptosis Cytolysis can be undertaken by amoebapores, a family of peptides capable of forming pores in lipid bilayers in animal models of liver abscess, trophozoites induced apoptosis via a non-Fas and non–tumor necrosis factor-α1 receptor pathway The amoebapores, at sublytic concentrations, can also induce apoptosis infection cycle: ingestion of E. histolytica cysts from the environment excystation in the terminal ileum or colon to form highly motile trophozoites after colonizing the colonic mucosa, the trophozoite may encyst it is then excreted in the feces or may invade the intestinal mucosal barrier and gain access to the blood stream and disseminate to the liver, lung, and other sites. excreted cysts reach the environment to complete the cycle processes of encystation and excystation are poorly understood E histolytica is, thus far, the only Entamoeba species definitely associated with disease; the others are considered nonpathogenic Epidemiology overall prevalence is ~4% groups predisposed to amebic colitis very young patients, pregnant women, recipients of corticosteroids, malnourished individuals
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This note was uploaded on 02/18/2012 for the course PAS 600 - 601 taught by Professor Garrubba during the Fall '10 term at Chatham University.

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EntomoebahistolyticaCO - Amebiasis (caused by Entomoeba...

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