Pinworm

Natural Habitat

The human large intestine; they are found globally, especially in temperate climates and among children.

Diet & Feeding

They feed on content in the human colon and epithelial cells.

Behavior Patterns

The life cycle is entirely within humans. At night, gravid females migrate out of the anus to lay thousands of eggs on the perianal skin, which causes intense itching. Eggs are spread via the fecal-oral route.

Risks & Benefits

Risk: Causes Enterobiasis, characterized by perianal itching, restless sleep, and irritability. Benefits: None; they are obligate parasites.

Identified on: 3/25/2026