Pinworms (threadworms)

What are pinworms?  

Pinworms are tiny (5 to 13 millimetres), thread-like, white worms that can live in the colon and rectum of humans. They are very common in children. Pinworms are not dangerous.

While the infected person sleeps, female pinworms lay thousands of eggs in the folds of the skin around the anus.

What are the signs and symptoms of pinworm?

Signs and symptoms are often seen 1 to 2 months after exposure and include: 

  • Itching around the anus (bum) or vaginal area.
  • Itching throughout the night.

Many will not have any signs and symptoms.

How is it spread?

Pinworms can be spread: 

  • From person-to-person contact via a fecal-oral route (e.g., unwashed hands). 
  • Transmission of eggs by hand to mouth, after touching infected surface. 

How long are they contagious?

  • As long as the parasite deposits its eggs on the infected person’s perianal skin.
  • Eggs can survive on surfaces up-to 2 weeks (e.g., bed linens, towels, toys).

How do you control pinworm?

  1. Wash in the morning. Pinworms lay their eggs at night. Washing the anal area in the morning can help reduce the number of pinworm eggs on the body.
  2. Change underwear and bed linen.
  3. Launder in hot water. Wash bedsheets, underwear, washcloths and towels in hot water to help kill pinworm eggs. Dry on high heat.
  4. Don't scratch. Avoid scratching the anal area, trim your child's fingernails and discourage nail biting.
  5. Wash your hands. To reduce your risk of getting or spreading an infection, wash your hands thoroughly after having a bowel movement or changing a diaper and before eating.

Should I see healthcare provider?

Yes, contact your healthcare provider if you think you or your child has pinworm. They can be treated with medication. School exclusion is not recommended.

Pinworms are not reportable to the Health Unit.

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