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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

Frequently asked questions

What is Cyclospora cayetanensis?

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.

What are the lab clues for Cyclospora cayetanensis?

Lab clues for Cyclospora cayetanensis include Modified acid-fast stool oocysts (variable uptake), Blue oocyst-wall autofluorescence under UV, Oocyst ~8-10 microns vs Cryptosporidium ~4-6, and Not infectious until sporulated.

What is Cyclospora cayetanensis commonly confused with?

Cyclospora cayetanensis is commonly confused with Cryptosporidium and Cystoisospora belli.

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 foundations - sourceNCBI Bookshelf: Medical Microbiology organism chapters - sourceCDC: CDC disease and public-health topic pages - source