Cause
Pinworm infection is caused by an intestinal roundworm called Enterobius vermicularis.
Pinworms are small, threadlike roundworms found primarily in the colon and rectum. The life cycle of the pinworm—egg, larva (immature stage), and mature worm—takes place inside the human body and requires from 3 to 6 weeks to complete.
The pinworm is the most common roundworm parasite in temperate climates—even in areas that have to good sanitation practices.