Oxyuris equi

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Revision as of 09:57, 2 June 2010 by Bevpanto (talk | contribs) (Text replace - 'pruritis' to 'pruritus')


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OXYURIS EQUI

General

  • Pinworm; caecum; large intestine; rectum.
  • Very common.

Morphology

  • Female worms, <10cm long, white, long pointed tail.
  • Male worms, <1cm (difficult to see).

Life-Cycle

  • Adults in lumen of colon.
  • Female migrates to anus, lay eggs on perianal hair (white streaks on hair; operculate eggs, 80-90µm, flattened on one side).
  • Eggs fall to ground, L3 develops inside egg, ingested, L3 invades colonic mucosa, emerges as L4 matures.
  • Prepatent period = 5months.

Pathogenicity

  • Larvae (L4) - feed on colon mucosa, nip off epithelium, not true plug-feeders (erosions).
  • Adults - non-pathogenic, feed on gut contents; but egg-laying activity of female worms irritant (pruritus ani), broken hair and bare patches over rump and tail head (seat itch).

Diagnosis

  • Clinical signs.
  • Egg streaks on perianal hair (sample using sellotape, place on slide).
  • Faeces on gound (adult female worms).

Control

  • Regular anthelmintic treatment.
  • Sponge perianal region frequently when clinical signs present (scald sponge after).