morphology

Last reviewed 06/2021

E. vermicularis (threadworm/pinworm):

  • is a member of the order Oxyurida
    • male pinworm is about 2–5 mm in length and no more than 0.2 mm wide. The male worms are haploid
    • females are diploid and reach a length of 8–13 mm and a width of up to 0.5 mm. The female worms are light yellowish white and have a thin, long, sharply pointed tail
    • eggs are:
      • 50–60 micrometers by 20–32 micrometers
      • have a smooth, clear outer capsule
      • eggs are are flattened on one side
      • are destroyed by ultraviolet lamps, dry heat and sunlight. The eggs are resistant to various 'cleaning mechanisms' including chlorination in swimming pools, hydrocyanic gas, paradichlorobenzene, and naphthalene