PetriKey

Parasite

Giardia duodenalis

Flagellated protozoan with cysts

jee-AR-dee-uh LAM-blee-uh

parasiteprotozoaflagellatecystwater

High-yield clue

Flagellated protozoan + cysts + waterborne exposure clue; G. lamblia is a common synonym.

Overview

A flagellated protozoan, also called G. lamblia or G. intestinalis, used to teach cyst ingestion, waterborne transmission vocabulary, and malabsorption-style educational clues.

Classification

  • Protozoan
  • Flagellate
  • Cyst/trophozoite life-stage vocabulary

Lab & identification clues

  • Ova/parasite exam vocabulary
  • Antigen test concept
  • Pear-shaped trophozoite teaching image

Associations

  • Waterborne outbreak vocabulary
  • Daycare/travel educational cases
  • Malabsorption clue

Commonly confused with

  • Entamoeba histolytica
  • 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.

CDC DPDx: CDC DPDx giardiasis naming and lifecycle overviewsourceOpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource