"Once inside the body, the stomach acid digests the water flea, but not the guinea worm larvae sheltered inside. These larvae find their way to the small intestine, and then pass into the body cavity. During the next 10–14 months, the female copulates with a male guinea worm. The small male (1.2–2.9 centimeters, 0.5-1.1 inches, long) dies and is absorbed into the larger female. The female develops into its full length of 60–100 centimeters (2–3 feet) long and a narrow width similar to that of a cooked spaghetti noodle. Having mated, the adult female is packed with thousands of tiny larvae. The worm migrates to the area of the body from which it will emerge, which, in more than 90% of all cases, is on one of the lower limbs.
A blister develops on the skin at the site where the worm will emerge. This blister causes a very painful burning sensation, and, within 24 to 72 hours of its appearance, will rupture, exposing one end of the emergent worm. To relieve the burning sensation, infected persons often immerse the affected limb in water. When the blister, which shortly becomes an ulcer or open sore, is submerged in water, the adult female releases a milky white liquid, containing hundreds of thousands of guinea worm larvae, into the water. Over the next several days, the female worm is capable of releasing more larvae whenever it comes in contact with water. These larvae contaminate the water supply and are eaten by copepods, thereby repeating the lifecycle of the disease, as described above."
http://en.wikipedia.org/wiki/DracunculiasisNow you know, and you probably wish you didn't.