Pinworm
Scientific Name: Enterobius vermicularis
Order & Family: Order: Oxyurida, Family: Oxyuridae
Size: Females are 8-13 mm; males are much smaller, 2-5 mm.
Natural Habitat
The human gastrointestinal tract, specifically the large intestine and rectum.
Diet & Feeding
Intestinal contents and nutrients found within the human host's digestive system.
Behavior Patterns
Nighttime activity where gravid females migrate out of the anus to lay thousands of eggs on the perianal skin, causing itching ('pruritus ani').
Risks & Benefits
Risk: Causes Enterobiasis, a common parasitic infection leading to itching, restless sleep, and irritability. Ecosystem: No known benefits; strictly a human parasite.
Identified on: 2/17/2026