About guinea-worm disease

© WHO

Guinea-worm disease is caused by the parasitic worm Dracunculus medinensis or "Guinea-worm". This worm is the largest of the tissue parasite affecting humans. The adult female, which carries about 3 million embryos, can measure 600 to 800 mm in length and 2 mm in diameter. The parasite migrates through the victim's subcutaneous tissues causing severe pain especially when it occurs in the joints. The worm eventually emerges (from the feet in most of the cases), causing an intensely painful oedema, a blister and an ulcer accompanied by fever, nausea and vomiting.

Infected persons try to relieve the burning sensation by immersing the infected part of their body in local water sources, usually ponds water. This also induces a contraction of the female worm at the base of the ulcer causing the sudden expulsion of hundreds of thousands of first stage larvae into the water. They move actively in the water, where they can live for a few days. More details.

For further development, these larvae need to be ingested by suitable species of voracious predatory crustacean, Cyclops or water fleas which measure 1–2 mm and widely abundant worldwide. In the cyclops, larvae develop to infective third-stage in 14 days at 26°C.

When a person drinks contaminated water from ponds or shallow open wells, the cyclops is dissolved by the gastric acid of the stomach and the larvae are released and migrate through the intestinal wall. After 100 days, the male and female meet and mate. The male becomes encapsulated and dies in the tissues while the female moves down the muscle planes. After about one year of the infection, the female worm emerges usually from the feet releasing thousands of larvae thus repeating the life cycle.

No drug is available to prevent or heal this parasitic disease – exclusively associated with drinking contaminated water. Dracunculiasis is, however, relatively easy to eliminate and eventually eradicate.

Guinea-worm disease is rarely fatal. Frequently, however, the patient remains sick for several months, mainly because:

• The emergence of the worm, sometimes several, is accompanied by painful oedema, intense generalised pruritus, blistering and an ulceration of the area from which the worm emerges.
• The migration and emergence of the worms occur in sensitive parts of the body, sometimes the articular spaces can lead to permanent disability.
• Ulcers caused by the emergence of the worm invariably develop secondary bacterial infections which exacerbate inflammation and pain resulting in temporary disability ranging from a few weeks to a few months.
• Accidental rupture of the worm in the tissue spaces can result in serious allergic reactions.

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