Guinea worm disease or dracunculiasis is vying with poliomyelitis to be the second human disease after smallpox to be eradicated. It will be the first human disease eradicated without using vaccines (or medicines). Eradication will be achieved by changing behaviour, a cause for optimism that other types of behaviour change are possible. The people who will benefit are among the poorest on the planet.
Dracunculus are long, thin nematode roundworms and the name means ‘little dragons’. The disease was described by the Egyptians over 3500 years ago and by the Greeks. Dracunucliasis occurs mainly in Africa but also in India, Pakistan and Yemen. The name Guinea worm disease was given by 17th-century European explorers visiting the West African coast of Guinea.
The disease is characterised by nodular skin lesions and can be eliminated because humans are the principal host and apparently the primary means of spread, although Dracuncula can cause nodular skin lesions in other mammals including cattle. The disease is transmitted by drinking stagnant water contaminated with Guinea worm larvae, which are always carried on water fleas (Cyclops). Gastric acid kills the water fleas but not the larvae, which mature into female and much smaller male worms. The males die after mating and are absorbed, while the females grow up to a metre long and migrate over months to the skin, usually of the foot or leg, to form excruciatingly painful blisters. Bathing the foot causes the worm to release eggs into the water, which develop into larvae and the cycle continues.
Pain can be debilitating enough to prevent walking. The traditional way of getting rid of the worm is by wrapping it round a stick, and rotating the stick is also painful and can take anything from hours to months (see Fig. 1). This ancient technique may be the origin of the rod and twined serpent carried by Aesculapius (or Asclepius), the Greek god of medicine and healing. The serpent-entwined rod is often used as a medical symbol (see Fig. 2) and is itself the possible origin of the white pole with the helix of stripes (red in the UK, red and blue in the USA) seen outside barbers' shops, indicating the traditional link between surgeons and barbers.
In poor communities, prevention is best achieved by filtering drinking water using fine-mesh cloth filters to remove the Cyclops water fleas. In addition, cases need to be detected, their lesions washed to reduce numbers of eggs and they need to be persuaded not to set foot in community drinking water.
In 1986, there were an estimated 3.5 million cases of Guinea worm disease globally. At this time, the philanthropic Carter Center, established by former US President Jimmy Carter, spearheaded a global campaign of eradication, in conjunction with the US Centers for Disease Control, WHO and UNICEF, and with later significant financial support from the Bill & Melinda Gates Foundation and the UK Department for International Development. The Sudan Civil War impeded the programme, which has nonetheless been stunningly successful, with only 807 cases detected in 2011, almost all in war-torn South Sudan. The cost of eradication, although considerable at about $375 million, is less than the cost of smallpox eradication more than 30 years earlier. It has been argued convincingly that a disease-centric approach to developing countries does not solve their underlying problems of poverty and health inequality, but improving health systems is notoriously difficult, while focusing on an achievable target encourages health workers and donors. The Guinea worm programme may also provide valuable training of local health-care workers.
We would not be humans if we agreed on everything (or anything). Vermiphiles do not despair. There is a website dedicated to saving the Guinea worm, ‘the world's most endangered species’. To those of us less devoted to worms, however, the story of the Guinea worm is an inspiring one of philanthropic vision and hard work bringing about behaviour change to improve the lives of millions. It is particularly uplifting that this is a story of the rich helping the poor.