Pinworm Infections In The United StatesAug 7th, 2013 | By Jacob | Category: Health
By Lynette Norris
Greene Publishing, Inc.
It’s not a nice or pleasant subject, but pinworm infections are the most common intestinal parasite infection in the United States and Western Europe. Each year, around 40 million cases of pinworms are diagnosed in the U.S. alone. Pinworms live and thrive in temperate zones rather than tropical climates, and they are a problem all around the globe. Because the eggs are so easily transmitted between people, as well as from environmental surfaces to people, pinworms can occur in affluent as well as impoverished societies. The pinworm is a type of roundworm or nematode that infects humans and mammals. So far, three species of pinworm have been identified, but only one species, the Entrobius vermicularis, infects human hosts. The worms are small, thin and white, almost translucent, growing to a length of 1/4 to 1/2 inch, and are about as big around as a bit of sewing thread. In fact, they are known as “threadworms” in the United Kingdom and Australia. How does a person get an infection? Pinworm eggs are hardy, and can live on household surfaces such as bedding, clothing, furniture, toys or bathroom fixtures for two to three weeks. They are microscopic in size and only barely visible to the naked eye when thousands and thousands of eggs are stuck together in very tiny translucent clumps. The eggs have a sticky surface when first laid, and are initially laid on the skin just outside the anus, where they can then be transferred to underwear, bedding, other clothing, and even fingers. If the infected person experiences anal itching and scratches the area, the dislodged eggs can adhere to fingers and be transferred to other surfaces or become stuck under fingernails. Household pets can carry pinworm eggs on their fur without become infected themselves. Infected bedding can contain literally hundreds of thousands of dislodged eggs. If this infected bedding is shaken out, the eggs can become airborne, attaching themselves to particles of dust, where they can be breathed in. However, the most common means of transmission is ingesting the eggs, whether from touching contaminated the hands to the mouth or eating contaminated food or beverages. The ingested pinworm eggs hatch in the intestines and develop into adults as the worms migrate through the intestinal tract. What is the life cycle of pinworms? Once the eggs are ingested, they hatch into larvae the duodenum, where the small intestine joins the stomach. The larvae grow rapidly into adults as they migrate through the intestinal tract, with the females generally surviving anywhere from 5 to 13 weeks and the males surviving about 7 weeks. The males and females mate in the ileum at the very end of the small intestine, after which the males die off and are passed out of the body with the stool. The females settle in the ileum, the caecum (the beginning of the large intestine), the appendix and the ascending colon. While their bodies fill with developing eggs (an estimated 11,000 to 16,000), the females attach themselves to the mucosa of the intestinal lining and ingest the contents of the colon. When they are ready to lay the eggs, they migrate toward the rectum and emerge outside the human body while the host sleeps, moving across the folds of anal skin, depositing eggs. Once this process is over, the female dies. What is the effect on the host? The infected person rarely experiences any symptoms other than anal itching, and some people with very mild infections do not even have the itching. However, in other cases, the itching can be so severe and bothersome that it interferes with sleep, causing irritability and fatigue. In spite of the pinworm’s short life cycle, the host’s tendency for re-infection, especially if itching is present and scrupulous hygiene is not observed (especially thoroughly washing the hands after using the bathroom or changing diapers, and always before meals, together with avoiding touching the mouth with the fingers) a pinworm infection can last indefinitely. Who is most likely to get a pinworm infection? Pinworm infections are most common among school-age children, and people who live together in close quarters i.e., other family members, or people in an institutional setting. Infections occur in about equal numbers in both genders. Children who are thumb-suckers or finger-suckers, and people who are nail-biters (a good reason to STOP biting your nails, if you are a habitual nail-biter) are more likely to get an infection or keep re-infecting themselves. How are infections diagnosed? The definitive diagnosis is the finding of pinworm eggs, and this is often done with the “scotch-tape test.” The host presses a bit of sticky tape against the anal area immediately upon waking, usually for three days in a row, and takes the tapes to the health care provider, who examines the tape pieces under a microscope for pinworm eggs. How is it treated? Mild infections may not need treatment at all. After the pinworm lives out its life cycle in the host, it dies, and if the host frequently, carefully and thoroughly washes all underwear, nightclothes, bedding and other clothing to remove lingering eggs, washes his hands often with disinfecting soap and avoids touching his mouth with his hands, this infection will eventually clear up. If treatment is required – for example, if the infection is severe enough to cause gastro-intestinal discomfort or weight loss, or the itching is making sleep impossible, an oral medication will be prescribed. The most common anti-parasite medications used are Mebendazole and Albendazole. How can re-infection be prevented? Bathe immediately after waking up Wash pajamas, other nightclothes and bed sheets often Wash hands regularly and thoroughly, especially after using the bathroom or changing a diaper Change underwear every day Avoid nail biting or putting the fingers in the mouth Avoid scratching the anal area For more information about pinworm infections visit the websites www.mayoclinic.com/heath/pinwormDS000687 or www.nlm.nih.gov/medlineplus/pinworms.html