PetriKey

Parasite

Cryptosporidium

Acid-fast oocyst protozoan

krip-toh-spor-ID-ee-um

parasiteprotozoaoocystacid-fastwater

High-yield clue

Tiny acid-fast oocysts + waterborne diarrhea vocabulary.

Overview

A protozoan parasite used in coursework for oocyst vocabulary, waterborne outbreak framing, and modified acid-fast staining concepts.

Classification

  • Protozoan
  • Apicomplexan
  • Oocyst concept

Lab & identification clues

  • Modified acid-fast stain vocabulary
  • Antigen/PCR concepts
  • Oocyst morphology

Associations

  • Waterborne outbreak vocabulary
  • Immunocompromised-host severity framing
  • Chlorine-tolerant oocysts and recreational-water outbreak vocabulary

Commonly confused with

  • Giardia duodenalis
  • Entamoeba histolytica
  • Cyclospora

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 cryptosporidiosis oocyst and waterborne vocabularysourceOpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource