Pinworm - Enterobius vermicularis

This is a gross one! Pinworms are intestinal parasites of humans. They cause enterobiasis, the primary symptom of which is anal itching. It's most common in children.

The life cycle goes like this:
Infection occurs through self-inoculation (transferring the parasite to the mouth with hands that have scratched the anus) or through exposure to eggs in the environment (contaminated surfaces, clothes, sheets, etc.). Following ingestion, the larvae hatch in the small intestine and then the adults establish themselves in the colon. At full maturity, adult females migrate (nocturnally) outside the anus and lay eggs while crawling on the skin of the perianal area. This causes itching. The person itches their butt, contaminates surfaces or ingests the eggs, and then the cycle begins again.

*Whole mount slide