guinea worm

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A long threadlike nematode worm (Dracunculus medinensis) of tropical Asia and Africa that is a subcutaneous parasite of humans and other mammals and causes ulcerative lesions on the legs and feet.

from The Century Dictionary.

• noun A formidable parasitic nematode or threadworm, Filaria medinensis, of extreme tenuity, from a few inches to several feet long, often infesting the human body, especially in hot countries. See Filaria.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a painful and debilitating infestation contracted by drinking stagnant water contaminated with Guinea worm larvae that can mature inside a human's abdomen until the worm emerges through a painful blister in the person's skin
• noun parasitic roundworm of India and Africa that lives in the abdomen or beneath the skin of humans and other vertebrates