Commonly referred to as the pinworm, this parasite currently afflicts approximately 400 million people worldwide. It has a very interesting life cycle. The pinworm's eggs are not deposited in the body of the host as is the case with most parasites. Instead, the impregnated female pinworm crawls out of the anus of the infected host to deposit her eggs over surrounding skin and clothes.

Pinworm eggs can be carried over large distances via dust in the air. Anyone can become infected by inhaling air or ingesting food that has been contaminated by these eggs. Women may also become infected should a pinworm crawl into a genital opening.

After the pinworm eggs enter your body, they hatch in your small intestine and then migrate to your cecum, appendix, or colon. Symptoms include gastrointestinal pain (due to the fact that the worms often attach themselves to the lining of the gut) and extreme itching. Children infected with pinworms become restless, irritable, and insomniac.