Pinworm

The human intestinal tract, primarily the large intestine and rectum, and human environments (bedding, clothing, dust).

The adult worms feed on the contents of the human digestive tract and intestinal debris.

Female worms migrate out of the anus at night to deposit thousands of microscopic eggs on the surrounding skin. This causes intense itching (pruritus ani), which leads the host to scratch and inadvertently transfer eggs back to the mouth or onto surfaces.

Risks include pinworm infection (enterobiasis) characterized by itching, restless sleep, and irritability. While generally harmless and common in children, they can cause secondary skin infections from scratching. They provide no known benefits to the host.