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Persistence Pays Off in Guinea Worm Fight
Rebecca Voelker
JAMA. 2007;298:1856-1857.
Last February, when Ernesto Ruiz-Tiben, PhD, accompanied former US President Jimmy Carter and his staff to Savelugu, Ghana, they were greeted with a heart-wrenching sight. More than 300 people, mostly children, flocked to a makeshift dracunculiasis clinic, hoping to obtain relief for pain so intense that the ancient Egyptians had called it a fiery serpent.
"It breaks your heart to see so much misery," says Ruiz-Tiben, director of dracunculiasis eradication at the Carter Center, a nonprofit human rights organization founded by the former president.
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Guinea worm eradication efforts include teaching simple interventions to stop transmission and treating those infected by removing worms and treating the lesions to avoid secondary infection. (Photo credit: Left: A. Poyo/The Carter Center; right: The Carter Center.)
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The trip to Savelugu was precipitated by news that more than 1000 cases of dracunculiasis, or guinea worm disease, had been reported in Ghana in January. Savelugu, a town of about 25 000 in the northern region, had 533 of those cases. The figures sounded an alarm—a year earlier, Savelugu had only 29 guinea worm cases in January and cases for the entire country for all of 2006 had totaled 4136, according to the World Health Organization.
Failure of the dilapidated water system that piped clean water from Tamale, the northern region's capital, to nearby Savelugu triggered the outbreak. With the system inoperable, townspeople turned to man-made dams or unscrupulous vendors, both of which provided water that harbored tiny copepods carrying infective larvae.
Drinking contaminated water allows guinea worm larvae to settle in the human abdomen, maturing until they grow up to 3 feet long. After an incubation period of about a year, the worms break through the skin in painful blisters. The cycle of infection is perpetuated when an infected person plunges the blister into soothing water and the worm releases thousands of larvae that will be ingested by copepods in the water.
"Guinea worm is an anachronism," says Ruiz-Tiben, a long-time leader in the fight against the disease. His voice is tinged with the kind of controlled anger that comes from witnessing decades of suffering from a preventable disease that is largely a product of poverty, lack of education, and government apathy or corruption. "In this day and age, it should not exist."
NOW, THE GOOD NEWS
The kind of outbreak that occurred in Savelugu is relatively rare, but far-flung public health professionals know setbacks can occur at any time. Even so, the big picture in guinea worm eradication is not one of towns and villages beset by continual disease outbreaks. In fact, say public health experts, work to eradicate guinea worm is a success story that, despite decades of persistent international effort, has not always been a high priority within endemic countries. A nonfatal disease, guinea worm infection competes for funds and personnel with such severe infectious diseases as malaria and AIDS, diseases that kill millions every year.
The Carter Center has spearheaded much of the eradication effort in the last 2 decades, with such partners as the US Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and the United Nations Children's Fund (UNICEF). If eradication is achieved, as expected, guinea worm would be only the second disease to achieve that distinction, behind smallpox. But it would become the first parasitic disease ever eradicated and the first disease to be eliminated without vaccine or medication.
When the WHO's World Health Assembly first adopted a resolution calling for guinea worm eradication in 1986, 3.5 million people in 20 countries had the disease. The number of endemic countries is now down to 9, all in Africa, and 4 of them are poised to report no cases this year. Besides Ghana, trouble spots are Sudan, now recovering from a 20-year civil war but harboring nearly half of all cases, and Mali, where an outbreak of 33 cases was reported in August. Ruiz-Tiben estimates that cases in 2007 will total about 10 000. "That's all the guinea worm that remains in the world," he says.
Today, the question is not so much whether guinea worm disease will be eradicated, but when. The World Health Assembly has set a 2009 target date for eradication after an earlier 1995 goal had come and gone. Public health experts say eradication dates are goals that help keep endemic countries on track, rather than fixed deadlines. But by some experts' accounts, guinea worm disease could be certified as eradicated before the more publicized polio is completely vanquished.
"Because there is no drug treatment and no vaccine, it is just a matter of being persistent with fairly simple interventions," says Dirk Engels, MD, PhD, coordinator of preventive chemotherapy and transmission control at WHO, which certifies countries as guinea worm free if no endemic transmission is detected for 3 years.
DIFFERENT CHALLENGES
Guinea worm has presented a different set of challenges than viral diseases targeted for eradication. In the smallpox campaign, vaccination was the key to success. Teams could vaccinate large regions in a short period of time and move on. While guinea worm eradication does not contend with such problematic issues as proper vaccine storage and transport, it requires an ongoing, systematic effort. "It's much more ponderous," says Ruiz-Tiben.
National eradication programs set up in villages throughout endemic countries generate monthly reports from every village in every endemic country. In 2006, there were reported to be 3583 endemic villages. These reports document minute details about water supplies, water filter use, and other methods to prevent disease. Another complex feature is guinea worm's 1-year incubation period compared with perhaps weeks in viral illnesses. It simply takes longer for health workers to know whether interventions to stop transmission have been successful.
Those interventions are low-tech and low-cost. They consist primarily of filtering drinking water, keeping infected individuals from wading into sources of drinking water, and stepping up health education and community willingness to tackle the disease. Equally important is case containment, which requires health workers to clean the blisters, gradually pull out the worm (a process that can take weeks to months), disinfect the lesion, and bandage it to prevent secondary infection. The Carter Center has distributed tens of thousands of medical kits to aid case-containment efforts.
Behavior modification plays a big role, says Barnett Cline, MD, PhD, professor emeritus, Tulane University School of Public Health and Tropical Medicine, New Orleans, La. But changing behaviors in culturally and geographically diverse regions takes finesse. Cline recalled working in a remote district of Pakistan during the early days of eradication efforts. Families there lived in compounds, each with its own cistern to collect precious rainwater during the short rainy season. "They were fiercely independent people," he says.
Infected individuals would walk into the cisterns to collect water, releasing thousands of disease-causing larvae. At the same time, water treated with the larvicide Abate appeared cloudy and tasted different, giving rise to suspicions that it would poison or sterilize local populations. But by talking with community elders who relayed public messages about breaking the transmission cycle, Cline and his colleagues achieved their eradication goal in the district.
BANG FOR THE BUCK
Since the early 1980s, guinea worm eradication has been conducted on a shoestring budget, costing a total $225 million, according to the Carter Center. It is money well spent, experts say. A 1997 cost-benefit analysis by the World Bank and the Carter Center showed that every US $1 spent on guinea worm eradication produced $1.29 in increased agriculture production. "Investing in improving the health of the population will have beneficial effects in the economic outlook of the country," says Ok Pannenborg, MD, JD, a senior health advisor at the World Bank.
But getting to the last, most difficult-to-reach cases can become very expensive, Pannenborg adds. The World Bank is working to implement innovative, low-cost ways to spur eradication programs in Sudan. One is a barter system in which local entrepreneurs are trained to deliver information, water filters, larvicide, and some treatment services in their communities in return for gum arabic, a substance they can use to make and sell such products as cosmetics, watercolor paints, and shoe polish.
Economic development is an important issue in combating guinea worm disease, notes Ruiz-Tiben. But with eradication close at hand, he cautions that continued vigilance also is a critical commodity. Surveillance networks that have taken decades to build cannot let down their guard.
"Guinea worm never sleeps," says Ruiz-Tiben.
| Guinea Worm and Beyond
The lasting legacy of guinea worm eradication efforts will go beyond the elimination of human suffering from a single disease. Public health experts have built a guinea worm infrastructure that can be used to lower the burden of other diseases that afflict some of the world's poorest, most remote regions.
"There is a village-based system for guinea worm," says Anders Seim, MD, executive director of Health & Development International, a nongovernmental organization based in the United States and Norway. Local volunteers in thousands of African villages help report transmissions every month to the World Health Organization (WHO), which in turn distributes that information to the international health community.
While the WHO would like to use the village reporting systems to help control other worm infections, including schistosomiasis and onchocerciasis, Seim is taking a somewhat different approach. He is working in Niger to use these village-based reporting systems to reduce cases and improve treatment for obstetric fistula, a chronic opening between the vagina and bladder or the vagina and rectum that results from obstructed labor that lasts several days. The WHO estimates that 2 million women, most in Asia and Africa, have the condition.
Seim says the village volunteers could help educate pregnant women and their families about the condition, and inform them about the criteria for seeking medical attention. "We can prevent this tragedy, this indignity," he says.—R.V.
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