Pinworm

The human large intestine; eggs are commonly found on bedding, clothing, and household surfaces.

Intestinal contents and cellular debris within the human host.

At night, female worms migrate out of the anus to deposit eggs on the surrounding skin, causing intense itching. This is a common parasitic infection, especially in children.

Risk: Causes enterobiasis, leading to itching (pruritus ani), disturbed sleep, and irritability. While generally harmless, heavy infestations can cause secondary skin infections. Benefit: None.