PetriKey

Disease

Amebiasis

Bloody dysentery plus liver abscess

am-uh-BYE-uh-sis

protozoafecal-oraldysenteryliver-abscesstropical

High-yield clue

Bloody dysentery with flask-shaped colonic ulcers and a possible right-upper-quadrant 'anchovy-paste' liver abscess is the classic amebiasis clue.

Overview

A colonic protozoal infection by Entamoeba histolytica, studied for invasive bloody dysentery and its extraintestinal liver abscess.

Classification

  • Protozoal enteric syndrome
  • Entamoeba histolytica infection
  • Fecal-oral cyst ingestion
  • Invasive and inflammatory

Lab & identification clues

  • Trophozoites with ingested red cells (erythrophagocytosis) vocabulary
  • Flask-shaped colonic ulcer vocabulary
  • Serology and stool antigen concept

Associations

  • Transmission: fecally contaminated food/water and oral-anal contact
  • Amebic dysentery with bloody stools and abdominal pain
  • Amebic liver abscess ('anchovy paste') vocabulary
  • Endemic where sanitation is poor / tropical regions

Commonly confused with

  • Bacillary dysentery (Shigella)
  • Giardiasis
  • Nonpathogenic Entamoeba dispar

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource