Pinworm

The human gastrointestinal tract, primarily the large intestine and rectum.

Intestinal contents and materials found in the human digestive system.

Adult females migrate out of the anus at night to lay thousands of eggs on the surrounding skin. The movement causes itching, leading to the spread of eggs via the hands to surfaces or other hosts.

Causes enterobiasis, an infection characterized by intense perianal itching. While generally not dangerous, it is highly contagious and can lead to secondary skin infections or disrupted sleep. There are no ecosystem benefits.