Dracunculosis is an infection caused by a parasitic worm known as Dracunculus medinensis, the guinea worm. Infected water fleas release the larvae of the worm into drinking water. Ingestion of contaminated water causes the larvae to migrate from the intestines via the abdominal cavity to the tissue under the skin. The larvae mature and release a toxic substance that makes the overlying skin ulcerate. After treatment, symptoms disappear and the worms can be safely removed from the skin.
Dracunculosis is characterized by chronic skin ulcers. Tissue under the skin is infiltrated by developing larvae of the parasitic worm known as Dracunculus medinensis, or Guinea worm. A female worm ready to release larvae produces stinging elevated spots (papules), causing redness and itching of the skin. These symptoms may be an allergic reaction to the parasite. The spots form blisters and later rupture, developing into painful ulcers. Multiple ulcers (usually on the legs) are common. Without treatment, the worms are absorbed or protrude from the skin over a period of several weeks.
The cause of dracunculosis is the consumption of water contaminated by the larvae of the parasitic worm Dracunculus medinensis, which live in an intermediate host in the water. The larvae are released from the intermediate host while in the stomach, where they mate and grow. This stage lasts for as long as a year. The female apparently survives this process and may grow to three feet in length. The symptoms and characteristic ulcers and infections occur when the female moves from the stomach or intestine to tissues under the skin.
In 1986, there were approximately 3.2 million cases of dracunculosis worldwide. However, due to the efforts of several national and international organizations in cooperation with local governments, the incidence of the disease has significantly decreased. According to current estimates, there are now fewer than 100,000 cases of dracunculosis worldwide, with the remaining cases primarily occurring in Sudan and certain countries in West Africa, such as Nigeria and Niger.
In individuals with dracunculosis, the condition is diagnosed based upon characteristic symptoms (e.g., fever, pain, and blistering and ulceration of the affected area) in association with the emergence of the adult worm through the individual's skin.
The administration of certain medications that are destructive to worms (antihelmintic therapy), such as metronidazole or thiabendazole, may help to alleviate associated symptoms. However, the effectiveness of such agents against the guinea worm's activity has not been demonstrated.
In most cases, once the worm begins to emerge, it may be gradually extracted by a few centimeters daily through winding of a small stick. Complete removal of the worm usually takes from weeks to months. In some cases, the worm may be surgically removed.
Boiling, appropriate chemical treatment, and filtering of contaminated drinking water may help to prevent transmission of dracunculosis.
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eMedicine – Dracunculiasis : Article by Shuvo Ghosh, MD