Entamoeba histolytica


  • Protozoan parasite, causes diarrhea, dysentery, invasive intestinal, and extraintestinal disease (e.g., amebic liver abscess).
  • Quadrinucleate cyst passed in feces transmits the infection. Excystation occurs in small intestine. Trophozoites migrate to large intestine and invade mucosa.[9]
    • Galactose/N-acetyl-D-galactosamine (Gal/GalNAc)-specific lectin mediates parasite adhesion to colonic mucin.
    • Invasion related to penetration of mucous layer, killing of epithelial cells by amoebapore (5kDa protein).
    • Deep ulcerations that spread in the submucosa form flask-shaped ulcers and cause microhemorrhages.
  • Immunity mediated by mucosal IgA recognition of Gal/GalNAc lectin.

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Last updated: July 31, 2016