There is really just one cause of a pinworm infection, which is swallowing the eggs of the pinworm. Pinworm infections are most common among children between the ages of five and 10, according to MayoClinic.com. The broader question most parents have is "How did my child come into contact with pinworm eggs?"
Exposure at Home
Female pinworms crawl out of the anus of an infected person and lays eggs around the anal opening. These eggs can fall off and get into bed linens or dirty clothing. When children or other family members come into contact with sheets and blankets that have pinworm eggs, they can infect themselves. The actions of the female pinworm can cause itching in the anal area, and if the infected person scratches, he can get eggs under his fingernails and spread them around to any surfaces he touches. Because of the ease with which eggs can be spread, if a single family member is infected, it is quite possible for the entire family to be infected. For this reason, your doctor may prescribe treatment for your entire household, notes MayoClinic.com.
Exposure at School
The National Institute of Allergy and Infectious Diseases reports that pinworm eggs can survive off the human body for up to two weeks. This means that if a child with an active pinworm infection goes to school or day care and touches her bottom without washing her hands afterward, it is possible for her to spread the eggs to other children through person-to-person contact, on toys or on doorknobs, and at water faucets. Frequent hand washing is the best way to prevent the spread of pinworm infection in a school or day care. Daily cleaning of shared toys and common areas can also prevent eggs from being transmitted among children.
Other Factors and Sources
Pinworm egg transmission is made easier in crowded living or school conditions simply because there is a greater risk of contact between an infected person and the surfaces or areas in which non-infected children may play or live. Pinworms are more common in temperate climates, which is part of the reason why they are the most common roundworm parasite infection in those climates, reports the NIAID. Pinworm eggs are so light, they can become airborne. While not common, this means that a child can become infected by simply breathing in and swallowing eggs.
Misconceptions
You cannot become infected with pinworms from your pets, reports the KidsHealth website. Household pets can be infected with pinworms, but they are a different species than those that infect humans. Pinworm infection does not mean a child lives in unsanitary conditions. The eggs are spread so easily that infections can occur even in households or institutions with the highest standards of cleanliness.
