This is the "Guinea worm". It is a large worm, up to 80 cm long, and is one of the oldest known human parasites. The female, who lives subcutaneously in humans, produces live larvae which cause ulcerations in the skin and are freed into water. The treatment for this parasite is noteworthy. The worm, protruding from an ulcer, is slowly wound onto a stick to pull it from the human.