PetriKey

Parasite

Entamoeba histolytica

Amebic trophozoite with RBC clue

en-tuh-MEE-buh his-toh-LIT-ih-kuh

parasiteprotozoaamebacystfecal-oral

High-yield clue

Trophozoites with ingested RBCs is the classic study clue.

Overview

An amebic protozoan used to teach cyst/trophozoite vocabulary, flask-shaped ulcer vocabulary, and ingested RBC morphology clues.

Classification

  • Protozoan
  • Ameba
  • Cyst/trophozoite concept

Lab & identification clues

  • Ova/parasite exam vocabulary
  • Antigen/PCR concepts
  • Ingested RBC teaching image

Associations

  • Amebic dysentery vocabulary
  • Liver abscess vocabulary
  • Fecal-oral transmission framing

Commonly confused with

  • Giardia duodenalis
  • Cryptosporidium

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