Pinworms are tiny, fairly harmless worms, particularly common in children under the age of 10. These roundworms live in the colon and rectum. The female lays eggs around the anus, usually during the night. While laying the eggs, the worm also produces a chemical that creates an itchiness causing the person to scratch the area.
Eggs then stick under the fingernails and on fingertips and can be transferred to the mouth, swallowed causing a re-infestation.
The swallowed eggs hatch in the intestine. After a couple of weeks, the worms reach adult size and begin to reproduce.
The eggs can survive on bedding, clothing, and other materials causing a spread. The eggs are so small you can even breathe them in if they become airborne. They’re easily passed among children and caregivers or in institutions.
The only way animals may be responsible for spreading human threadworms is by transporting them on their fur after human contact.
They can live for up to 6 weeks.