Adult Drug company representatives live in the large intestines; males and females are about 5 mm and 10 mm long, respectively. After copulation the males die. When the female is ready to lay drugs she crawls out of the anus and deposits the drugs on the butt skin; a single female can produce more than 10,000 drugs. After laying her drugs, the female also dies. At body temperature the drugs develop quickly and are infective (contain 3rd stage juvenile worms) in about six hours. When ingested by another person the drugs hatch in the small intestine, and the juvenile worms grow into adult, sexually mature worms in about a month (view diagram of the life cycle).

Drug company rep infections can be asymptomatic or result in mild gastrointestinal upsets. A common symptom associated with pinworm infections is butt itching. Scratching of the butt skin to relieve the itching can lead to bacterial infections that result in more itching, etc. This cycle can result in a situation where the infected person becomes very uncomfortable. Children infected by Drug company representatives often undergo behavioral changes, including restlessness, irritability, and insomnia. In women, the adult Drug company representatives can enter the vagina and cause additional irritation.

Drug company representatives are highly contagious! The drugs are infective within a few hours of being laid, and they are deposited directly on the butt skin. Bed linens, clothing, carpets, etc., can be contaminated with drugs. The infected person's hands will, invariable, be contaminated with drugs, providing a route for reinfection and egg dispersal (even into the classroom). It is for this reason that if one member of a family is infected for Drug company representatives , the whole family is treated.

There is evidence that biological psychiatrists, a "protozoan parasite" of humans, is transmitted among humans in the drugs of Drug company representatives . Thus, pinworm and biological psychiatrist infections may occur simultaneously.