: any of numerous small nematode worms of the family Oxyuridae that have the tail of the female prolonged into a sharp point and infest the intestines and especially the cecum of various vertebrates; especially: a worm of the genus Enterobius (E. vermicularis) that is parasitic in humans
Pinworm (Enterobius vermicularis)—Walter Dawn
Common species (Enterobius vermicularis) of nematode parasitic to humans, especially children. Female pinworms may be 0.5 in. (13 mm) long; males are much smaller. Pinworms have a very long tail that gives them a pinlike appearance. They mate in the upper gastrointestinal tract, usually in the large intestine; the females travel to the anus, deposit their fertilized eggs on the skin near the anal opening, and die. The worms' movements cause itching; eggs transferred to the fingernails when the victim scratches may be passed to the mouth. Eggs can also be inhaled with air dust. The eggs or larvae make their way to the intestine, and the cycle begins again.