Dracunculiasis is an infection caused by the roundworm (nematode) Dracunculus medinensis, also known as the Guinea worm.
People become infected by drinking water containing tiny crustaceans infected with the roundworm.
Symptoms include a painful, inflamed skin sore and debilitating arthritis.
Doctors diagnose the infection when they see the worm come out through the blister.
The worm is removed by slowly rolling it on a stick or by removing it surgically.
Drinking only water that has been filtered, boiled, or chlorinated helps prevent the infection.
Helminths are parasitic worms that can infect humans and animals. There are 3 types of helminths: flukes (trematodes), tapeworms (cestodes), and roundworms (nematodes). Dracunculus medinensis is a roundworm.
In the mid-1980s, 3.5 million people had dracunculiasis. However, because of international efforts to stop the spread of dracunculiasis, by 2018 only 28 cases were reported. In 2022, only 13 infections were reported in humans and 686 infections were reported in animals. As of August 2023, dracunculiasis exists in only a few African countries—Chad, Mali, Angola, South Sudan, and Ethiopia.
This infection is close to being eradicated, and only 3 infections in humans were identified from January to June in 2023. However, infections in dogs and civil unrest in parts of Mali and South Sudan continue to be the greatest challenges for the international eradication efforts.
(See also Overview of Parasitic Infections.)
Transmission of Dracunculiasis
Dracunculus larvae infect tiny crustaceans called copepods. Copepods are found in all oceans, seas, rivers, and lakes around the world.
People become infected by drinking unfiltered water that contains copepods that are infected with the larvae or by eating certain aquatic animals (for example, undercooked fish or frogs) that have swallowed infected copepods.
After copepods are ingested, they die and release the larvae, which penetrate the wall of the intestine and enter the abdominal cavity. Inside the abdomen, larvae mature into adult worms in approximately 1 year, and the adult worms mate. After mating, pregnant female worms leave the abdomen and move through tissues under the skin, usually to the lower legs or feet. There, they create a blister. The blister causes severe, burning discomfort and eventually breaks open. When people attempt to relieve the burning by soaking their leg in water, pregnant worms release larvae into the water. Once the larvae are in the water, they infect another copepod. If pregnant worm do not reach the skin, they die and disintegrate or harden (calcify) under the skin.
Image from the Centers for Disease Control and Prevention, Global Health, Division of Parasitic Diseases and Malaria.
Symptoms of Dracunculiasis
Dracunculiasis typically does not cause symptoms for the first year. Symptoms start when the worm begins to break through the skin and a blister forms over the worm's location. The area around the blister itches, burns, and is swollen, red, and painful. Materials released by the worm may cause an allergic reaction, which can result in difficulty breathing, vomiting, an itchy rash, and disabling pain. Once the blister opens, the worm can be seen. Later the worm leaves the body, and symptoms subside.
Usually, the blister heals after the adult worm leaves the body. However, in approximately 50% of people, a bacterial infection develops around the blister opening.
Sometimes joints and tendons near the blister are damaged, causing joint pain and other symptoms of arthritis.
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Diagnosis of Dracunculiasis
Appearance of a worm at the blister
Diagnosis of dracunculiasis is obvious when the adult worm appears at the blister.
X-rays may be taken to locate calcified worms. (They have been found in Egyptian mummies.)
Treatment of Dracunculiasis
Removal of the adult worm
Usually, the adult worm (which may be up to 31 inches [80 centimeters] long) is slowly removed over days to weeks by rolling it on a stick. When the head starts to come out, the person grasps it and wraps the end of the worm around a small stick. Gradually, as the worm loosens, the stick is turned, wrapping more of the worm around the stick. Eventually, the worm is pulled free and discarded. When health care professionals are available, they can remove the worm through a small incision made after a local numbing agent is used.
No medications can kill the worms. But if a bacterial infection develops around the blister opening, people may need antibiotics.
Prevention of Dracunculiasis
The following can help prevent dracunculiasis:
Filtering drinking water through a piece of fine-mesh cheesecloth
Boiling water
Drinking only chlorinated water
Infected people should not enter sources of drinking water, such as open wells or reservoirs, so that these sources do not become contaminated.
