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What are pinworms?

Pinworms are tiny, white thread-like parasitic worms that live in the intestines. Female worms crawl out of the anus at night and lay their eggs in the folds of the skin.

What are the symptoms?

Symptoms include anal itching, sleeplessness, irritability, and anal irritation due to scratching. Pinworms may also be present without symptoms. Pinworms are a nuisance, not a disease. They are very common in children and spread easily among children and staff in childcare facilities.

How are pinworms spread?

Pinworms are spread from person to person. Pinworms of animals are not spread to people. Pinworms are spread when an uninfected person touches the anal area of an infected person (eg. during diaper changing), sheets or other articles contaminated with pinworm eggs and then touches their mouth, transferring the eggs and swallowing the eggs.

An infected person can spread pinworms by scratching the anal area, and contaminating food or other objects, which are then eaten or touched by uninfected persons. Pinworms can be spread as long as either worms or eggs are present. An uninfected person picks up pinworm eggs from an infected person's clothes, sheets or surroundings. The eggs can survive up to 2 weeks away from a human host.

How are they diagnosed?

A physician can do a simple test to check for pinworms by applying transparent adhesive tape to the perianal area and examining the tape microscopically for eggs. If they are found, the pinworms can be treated with medication. All household members or daycare attendees may need to be treated at once if several members are infected. However, the pinworms can reoccur if the person comes into contact with pinworm eggs.

How can I prevent them from spreading?

• Proper hand washing among children and adults, particularly before preparing or eating food and after using the toilet.
• Exclude a child with pinworms from school or childcare facility until 24 hours after the child has received the first treatment. The entire family may have to be treated to prevent reinfection.
• Discourage children from scratching the anal area.
• Keep fingernails short and discourage nail biting.
• Machine wash bed liners and hand towels using hot water and machine dry using a heat setting.
• Change frequently and clean underclothing and night clothes, preferably after bathing. Change sheets frequently.
• Clean and disinfect bathroom surfaces.
• Clean/vacuum sleeping and living areas daily for several days after treatment.

For more information please call Public Health at 519-376-9420 or 1-800-263-3456.