Pinworm

Human gastrointestinal tract, primarily inhabiting the cecum, appendix, and adjacent parts of the ascending colon.

Feeds on intestinal contents, mucosal cells, or bacteria within the human large intestine.

Nocturnal migration where gravid females move through the anus to deposit eggs on the perianal skin, causing intense itching. Life cycle occurs entirely in humans through ingestion of eggs.

Causes enterobiasis, an infection characterized by perianal itching (pruritus ani), irritability, and disturbed sleep. While generally not dangerous, it is highly contagious and requires medical treatment.