Dracunculus is a genus of spiruroid nematode parasites in the family Dracunculidae. The worms can reach a metre in length. If one simply pulls off the protruding head of the worm, the worm will break and leak high levels of foreign antigen which can lead to anaphylactic shock and fast death of the host. Hence it is important to remove the worm slowly (over a period of weeks). This is typically undertaken by winding the worm onto a stick (say, a matchstick), by a few centimetres each day. Life cycle All members of Dracunculus are obligate parasites of mammals or reptiles. Adult females reside just under the skin, and eventually form a blister in the host's skin through which they access the environment. When the blister comes into contact with water, the female releases several hundred thousand first-stage ("L1") larvae. L1 larvae must be ingested by a cyclopoid copepod, which serves as an intermediate host. Inside the copepod, the larvae develop to the third-stage ("L3"). Definitive hosts acquire Dracunculus by incidentally ingesting infected copepods while drinking water, or by consuming a paratenic host (e.g. a frog or fish) that has itself consumed a copepod. Inside the definitive host, the L3 larvae leave the digestive tract and migrate to deeper tissues, where within 60–70 days they undergo their final two molts to form sexually mature adults. Male and female adult worms then mate, and pregnant females migrate back to the host's skin – typically to an extremity – and form a blister to repeat the cycle. Following the release of her larvae, the female worm dies, and is either extracted by the affected animal, or falls back into the tissue and is calcified. Description Once released, the L1 larvae measure 0.3–0.9 millimeters in length and feature a very long tapered tail. As they develop into L3 larvae, they lose the tapered tail, broaden, and develop a tri-lobed tail; the lengths of most L3 larvae are unknown. Adults of both sexes are narrow yellow-white colored worms, with a rounded front-end, and a conical tail-end with a pointed tip. Females of different species within the genus tend to look similar, and can rarely be distinguished on morphology alone. The body of a fertilized adult female is almost completely filled by its uterus, distended with L1 larvae. Adult female Dracunculus worms are noted for their extraordinary length, with some growing up to 100 centimeters