PetriKey

Parasite

Trichinella spiralis

Encysted muscle larvae from undercooked pork

trik-ih-NEL-uh spih-RAL-iss

nematoderoundwormzoonosismusclefoodborne

High-yield clue

Undercooked pork (or wild game) leads to larvae encysting in skeletal muscle, with periorbital edema, myalgia, and marked eosinophilia.

Overview

A tissue nematode acquired by eating undercooked meat containing encysted larvae, the classic study model linking foodborne roundworm infection to muscle disease.

Classification

  • Nematode (roundworm)
  • Larvae encyst in striated skeletal muscle
  • Zoonotic, foodborne
  • No egg stage passed in stool

Lab & identification clues

  • Encysted larvae in muscle biopsy vocabulary
  • Marked peripheral eosinophilia
  • Serologic (antibody) testing concept

Associations

  • Undercooked pork or wild-game consumption
  • Periorbital/facial edema and myalgia vocabulary
  • Splinter hemorrhages association
  • Trichinellosis public-health framing

Commonly confused with

  • Taenia species
  • Toxocara species

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