Human pinworm parasite lifecycle. Diagram showing the life cycle of the parasitic nematode (pinworm) Enterobius vermicularis, cause of the common intestinal infection enterobiasis in humans. Human pinworm eggs are deposited on the perianal folds, making the area itchy. Self-infection occurs when a person scratches the perianal folds and ingests the eggs. Human pinworm infection can be treated by improving hygiene and using over-the-counter anthelminitic medicines such as mebendazole and pyrantel pamoate.