Victory over a parasite - the global eradication of Guinea Worm

Hooray for science! The New England Journal reports on the imminent eradication of the Guinea worm.

For those who haven't heard of this nasty little parasite, it is a really horrible infection to get. It starts with the ingestion of Dracunculus medinensis infected water. The larvae, when freed from their copepod carriers, migrate from the GI tract, copulate, work their way to the skin, and the adult worms then cause a painful, burning blister as they emerge. The human host, seeking relief, will often seek to immerse the blister in water - and when it bursts the cycle continues as the larvae are released.

Humanity can thank the Carter Center, the Bill and Melinda Gates foundation, the CDC, and World Health Organization for the following graph:

This is the number of Guinea Worm infections worldwide. Eradication efforts began in the early 80s.

Here is the NEJM summary

Thanks to the two-decade campaign against guinea worm disease, the global incidence has fallen from an estimated 3.5 million cases in 1986 to 25,217 in 2006.1 A slight increase in the reported incidence during 2006 is attributable to improved detection in newly accessible areas of southern Sudan.1 The eradication program has reduced the number of countries with endemic dracunculiasis from 20 in 1986 to 9 in 2006 (with 5 of the 9 having reported fewer than 30 cases each). The World Health Organization (WHO) has now certified 180 countries as free of guinea worm disease, and all countries where the disease was endemic have signed a WHO Geneva declaration pledging to wipe out the parasite by 2009.2 Whereas massive funding is funneled into campaigns to eradicate poliovirus, to control malaria and tuberculosis, and to prevent the spread of human immunodeficiency virus, guinea worm disease is about to be eradicated without any drug therapy or vaccine. Its demise will be proof that people can be persuaded to change their behavior through innovative health education.
...
Much has been written about the inadequacy of "vertical," single-disease programs that fail to focus on widespread reductions in poverty, on infrastructure development, and on the broad-based provision of primary care. But the Dracunculiasis Eradication Program is leaving a legacy of development in sync with the United Nations Millennium Development Goals. It has helped to improve the quality of water sources for communities that previously lacked access to clean and safe water, created jobs for the (often elderly) unemployed, and empowered volunteers, frequently inspiring them to pursue health-related employment. In communities where guinea worm was endemic, networks of women have been created for education campaigns; Ghana alone has 6500 female Red Cross volunteers assisting in the program, and in Benin newly created women's clubs have helped to stop transmission of the disease.3 School absenteeism has decreased as fewer children have become infected. Research in Mali had linked a 5% decrease in production of two food crops to guinea worm disease, and the annual economic losses due to guinea worm in three rice-growing Nigerian states was estimated to be over $20 million, but now agricultural productivity has improved.5 Thus, this vertical program has been shown to combat poverty, hunger, and even illiteracy (by decreasing school absenteeism), as well as to empower women -- all Millennium Development Goals.

One unmentioned aspect of this program, that I remember hearing about on NPR last year, was the problem of dealing with some people with funny overvalued ideas in the process of eliminating this disease. In this case, the idea that certain bodies of water were holy, and should not be treated - or even shown to outsiders - for fear of damaging their sanctity. The eradication effort convinced members of villages who knew where these water spots were to then de-sanctify them - usually by throwing in the body of a dead animal - so that the water could be treated and a horrible disease eliminated. An interesting conflict of religious ideas and public health concerns.

One forgets that in the United States we had our own nasty parasite that ate through flesh and was similarly eliminated through public health measures - the screw worm. It was endemic to North America - and still persists in the tropics. It was the larval stage of a fly that would leave its young in open wounds of animals - not actually a worm. The larvae - which unlike maggots would eat live flesh - would then emerge from the wounds causing pain. Attempts to extract them would cause them to bury themselves deeper into tissue (hence screw-worm). We eliminated them by using the sterile insect technique to eliminate the species.