Introduction to Diagnostic Medical Parasitology
Enterobius vermicularis is a common intestinal nematode of the large bowel. Pinworm infections often remain asymptomatic.
The short-lived female worm (about 1 cm in length) deposits its eggs once on the perianal skin. Within hours these eggs become infectious with a first-stage larva. If eggs are swallowed, these larvae hatch, moult twice in the intestine and become adults. Within 2 weeks, female adult worms may produce eggs.
- Distributed worldwide; more common in temperate climates
- Infections most frequent in children (auto-infections!)
- Humans are the only definitive host; no animal reservoir
- Attachment of the worms can elicit mild inflammation
- Rarely, worms are found in ectopic sites (appendicitis!)
- Most common symptom is perianal pruritus
- Disturbed sleep and restlessness
- Sometimes secondary infections of scratched skin
The female pinworms deposit their eggs on the perianal skin. Therefore they are not usually found in faecal samples. The adequate method to detect eggs is the cellulose tape test.
Adult female worms (8–13 mm long) may be seen around the anus or on the surface of a stool sample.
No tests developed
No tests available
Serology has no diagnostic value
Besides parasitological examination, no alternative strategy is needed.
Prevention and control
- Prevent autoinfection by hand washing, short fingernails, wearing underwear, regular washing of bedclothes
- Treatment of all family members to stop transmission
- Education in personal hygiene