Pinworm

Natural Habitat

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

Diet & Feeding

Intestinal contents and epithelial cells of the human colon.

Behavior Patterns

Nocturnal migration; gravid females crawl out of the anus at night to deposit eggs on the perianal skin, causing intense itching. Life cycle involves ingestion of eggs through contaminated surfaces (fomites) or hands.

Risks & Benefits

Risks: Causes enterobiasis, leading to anal itching, irritability, and restlessness. They are highly contagious parasites but generally not considered medically dangerous. Benefits: None to humans; they are obligate parasites.

Identified on: 2/15/2026