Dracunculiasis is infection caused by the roundworm Dracunculus medinensis. It causes a painful, inflamed skin sore and debilitating arthritis.

• People become infected by drinking water containing tiny crustaceans infected with the roundworm.
• A blister forms, with swelling, redness, and pain in the area around it, and the joints near the blister may be damaged.
• Doctors diagnose the infection when they see the worm at the blister.
• Drinking only water that has been filtered, boiled, or chlorinated helps prevent the infection.
• The worm is removed by slowly rolling it on a stick or surgically.

The infection occurs mainly in a narrow belt across several countries in southern Africa and in Yemen and only during certain seasons.

People become infected by drinking water containing tiny infected crustaceans, which are intermediate hosts for the worms. After ingestion, the crustaceans die and release the larvae, which penetrate the wall of the intestine. Larvae mature into adult worms in about 1 year. After mating, female worms move through tissues under the skin, usually to the feet. There, they create an opening to the skin so that when they release larvae, the larvae can leave the body, enter water, and find the crustacean host. If the larvae do not reach the skin, they die and disintegrate or harden (calcify) under the skin.

Symptoms and Diagnosis

Symptoms start when the worm breaks through the skin. A blister forms at the opening. The area around the blister itches, burns, and is inflamed—swollen, red, and painful. Materials released by the worm may cause an allergic reaction, which can result in difficulty breathing, vomiting, and an itchy rash. Symptoms subside and the blister heals after the adult worm leaves the body. In about 50% of people, bacterial infections develop around the opening for the worm. Sometimes joints and tendons near the blister are damaged.

Diagnosis is obvious when the adult worm appears at the blister. X-rays may be taken to locate calcified worms.

Prevention and Treatment

Filtering drinking water through a piece of cheesecloth, boiling water, and drinking only chlorinated water help prevent dracunculiasis.

Usually, the adult worm is slowly removed over days to weeks by rolling it on a stick. The worm can be surgically removed after a local anesthetic is used, but in many areas, this method is unavailable. People who also have a bacterial infection are sometimes given metronidazoleSome Trade Names
FLAGYL
to reduce inflammation.

Last full review/revision March 2007 by Richard D. Pearson, MD