PetriKey

Parasite

Trichuris trichiura

Whipworm with barrel-shaped bipolar-plug egg

trik-YOO-ris trik-ee-YOOR-uh

nematoderoundwormwhipwormsoil-transmittedintestinal

High-yield clue

Barrel- (lemon-) shaped egg with clear bipolar plugs is the classic identification clue; heavy infection is linked to rectal prolapse in children.

Overview

A soil-transmitted intestinal nematode (whipworm) named for its whip-like shape, used in coursework for its distinctive egg morphology and heavy-infection presentation.

Classification

  • Nematode (roundworm)
  • Soil-transmitted helminth
  • Whip-shaped adult
  • Resides in the large intestine (cecum/colon)

Lab & identification clues

  • Barrel-shaped egg with polar plugs at both ends
  • Eggs identified on stool examination
  • No larval lung migration (unlike Ascaris/hookworm)

Associations

  • Fecal-oral via embryonated eggs from soil
  • Heavy load linked to rectal prolapse and colitis vocabulary
  • Warm, humid tropical distribution
  • Poor sanitation epidemiology

Commonly confused with

  • Ascaris lumbricoides
  • Enterobius vermicularis

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