Pinworm (Enterobius Vermicularis)
A pinworm (“threadworm”) is a small, thin, white roundworm (nematode) called Enterobius vermicularisthat sometimes lives in the colon and rectum of humans. Pinworms are about the length of a staple. While an infected person sleeps, female pinworms leave the intestine through the anus and deposit their eggs on the surrounding skin.
Transmission
Pinworm is spread through the fecal-oral route, meaning transmission occurs from the anus to someone’s mouth through:
- Environment to Person by contaminated items, such as clothing, bedding, food or other objects.
- Person to Person direct contact with contaminated hands, often on the fingers or under fingernails.
Although anyone can become infected with pinworm, the following groups are more likely to become infected:
- Preschool and school-aged children.
- Household contacts of infected children.
- People in a hospital, nursing home or other group settings.
A person will remain infectious for as long as there are worms laying eggs on the skin around his or her rectum. Pinworm eggs can remain infectious in an indoor environment for two to three weeks. A person can also reinfect themselves or be re-infected by eggs from another person.
Symptoms
Not all infected people will have symptoms. If symptoms do occur, they are usually noticed one to two months after infection and will include:
- Itching around the rectum
- Difficulty sleeping and restlessness, as a result of itching
Diagnosis
A diagnosis of pinworm can be made by seeing the adult worms around the rectum. Consult a health care professional if you think you or your child has pinworms.
Treatment
Treatment shortens the length of time pinworm is spread. Your health care provider can prescribe medications to kill adult worms.
- Over-the-counter medications
- Prescription medications
All household contacts and caretakers of the infected person should be treated at the same time. If left untreated, itching and scratching associated with these infections may result in secondary bacterial infections. Some of these may be difficult to treat. Untreated people can continue to infect other people.
For more information about the treatment of pinworm, contact your health care provider or visit CDC - Enterobiasis - Treatment.
Prevention
- Hand washing is the most important preventive measure
- Wash hands frequently, especially after using the bathroom, scratching affected skin and before preparing meals and eating
- Good hygiene; infected people should:
- Shower every morning to help remove eggs on the skin and rectal area
- Cut fingernails regularly and avoid biting the nails and scratching around the anus
- Change underwear and bedding frequently to help prevent re-infection
- Avoid co-bathing and the reuse or sharing of washcloths during treatment and two weeks after the final treatment
Exclusion Guidance
Individuals with pinworms should not be excluded from work, school, or child care unless the general exclusions apply.