Pinworm

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

Absorbs nutrients from the host's intestinal contents and organic matter.

Nocturnal migration; adult females travel to the perianal area at night to deposit eggs, which causes intense itching (pruritus ani). Infection occurs via ingestion of eggs.

Risk: Causes enterobiasis, leading to itching, irritability, and disturbed sleep. Benefit: None (human parasite).