Pinworm infection

Pinworm infection (threadworm infection in the UK), also known as enterobiasis, is a human parasitic disease caused by the pinworm, Enterobius vermicularis. The most common symptom is itching in the anal area. The period of time from swallowing eggs to the appearance of new eggs around the anus is 4 to 8 weeks. Some people who are infected do not have symptoms.

The disease is spread between people by pinworm eggs. The eggs initially occur around the anus and can survive for up to three weeks in the environment. They may be swallowed following contamination of the hands, food, or other articles. Those at risk are those who go to school, live in a health care institution or prison, or take care of people who are infected. Other animals do not spread the disease. Diagnosis is by seeing the worms which are about one centimetre long or the eggs under a microscope.

Treatment is typically with two doses of the medications mebendazole, pyrantel pamoate, or albendazole two weeks apart. Everyone who lives with or takes care of an infected person should be treated at the same time. Washing personal items in hot water after each dose of medication is recommended. Good handwashing, daily bathing in the morning, and daily changing of underwear can help prevent reinfection.

Pinworm infections commonly occur in all parts of the world. They are the most common type of worm infection in Western Europe, Northern Europe and the United States. School-aged children are the most commonly infected. In the United States about 20% of children will develop pinworm at some point. Infection rates among high-risk groups may be as high as 50%. It is not considered a serious disease. Pinworms are believed to have affected humans throughout history.