PetriKey

Parasite

Cyclospora cayetanensis

Produce-linked acid-fast coccidian

sy-kloh-SPOR-uh ky-uh-tuh-NEN-sis

protozoacoccidianacid-fastfoodborneproduce

High-yield clue

Variably modified-acid-fast oocysts that autofluoresce blue under UV and are ~8-10 microns (about twice Cryptosporidium) is the key study clue.

Overview

An intestinal coccidian parasite whose oocysts require environmental sporulation before becoming infectious, so it spreads via contaminated fresh produce and water. It matters as the classic outbreak-associated watery-diarrhea coccidian.

Classification

  • Protozoa
  • Apicomplexa
  • Coccidian
  • Oocyst-forming intestinal parasite

Lab & identification clues

  • Modified acid-fast stool oocysts (variable uptake)
  • Blue oocyst-wall autofluorescence under UV
  • Oocyst ~8-10 microns vs Cryptosporidium ~4-6
  • Not infectious until sporulated

Associations

  • Imported fresh produce (raspberries, cilantro, basil) outbreaks
  • Fecal-oral via contaminated water
  • Prolonged/relapsing watery diarrhea vocabulary
  • Seasonal outbreak epidemiology framing

Commonly confused with

  • Cryptosporidium
  • Cystoisospora belli

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