Enterobiasis (Oxyuriasis)

  • It is caused by Enterobius vermicularis or pinworms
  • Manifested mainly in children.
  • Statistics: Size of the female worm -10mm; size of the male worm - 3mm; size of the ova - 50µm x 30µm.
  1. Transmission
  • Life cycle;


_Transfer of ova from the perianal area to fomites e.g. clothing and toilet seats

_Ova are picked up by the new host

_They are transmitted to the mouth, and swallowed.

_The ova are hatched and mature in the lower GIT (it takes 2-6wks)

_The female worm migrates, mainly at night, out of the anus to the perianal region and deposit the eggs



     _May occur through finger transfer of

    ova from the perianal area to the mouth.

_Retro-infection may occur where eggs are hatched in the anal-rectal area and the larvae migrate retrogradely to caecum.

  • Mainly asymptomatic
  • Restlessness
  • Perianal itching (the main symptom) and sometimes excoriations
  • Abdominal pain
  • Vaginitis and perianal lesions (though rare).
  • Seizure (rare)
  • Insominia (rare)
  • Worms in the perianal region (worms appear 1-2 hrs after retiring to bed and early in the morning).
  • Ova in the perianal region (collected early in the morning using cellophane tape).
  • Occasionally eggs in the urine, stool and vaginal smear.


Over 2 years: (children and adults): _Tabs/susp Albendazole 400mg stat


_Tabs Levamizole Adults: 120mg stat. Children 1-4 years: 40mg stat.  5-15 years: 80mg stat.


_Tabs Mebendazole 100mg BD x 3/7 or 500mg stat.


Tabs / susp Pyrantel pamoate 10mg/kg stat



Ivermectin 200 mcg/kg OD x 3/7Treatment is repeated after 10 days  as viable ova are excreted  at least 2 weeks after therapy.

  • Treatment rarely affects the ova
  • Antipruritic creams or ointments
  • Preventive measures include:

_Treatment of the whole household

_Regular washing of hands (especially after

   visiting the toilet)

_Morning shower

_Regular washing of fomites e.g. beddings, towels, clothes and toilet.

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