We human beings have a checkered history, but we deserve some credit for banding together to all but exterminate the wretched parasite that is the guinea worm.
As of the end of July, global health organizations had reported 53 new cases of guinea worm disease around the world. As many folks don’t know much about guinea worm, 53 might seem like a pretty scant number—it could equally signify outbreak or containment. But what that number indicates is actually tantamount to a revolution in healthcare. In 1986, health officials estimated that there were 3.5 million new cases of guinea worm disease annually across 20 countries. That means in just under three decades, we’ve eliminated more than 99 percent of cases, and restricted it to the most remote and troubled regions of four African countries: Chad, Ethiopia, Mali, and South Sudan.
At this pace, it’s likely that guinea worm will be the second human disease (and third disease overall) in history that we defeat—following the 1979 eradication of smallpox and the 2010 elimination of rinderpest in cattle. That means we’re closer to defeating this disease than polio, which counted over 300 new cases in 2013, often thought of as one of the great health campaigns of the modern era. But the conquest of guinea worm may be an even more extraordinary medical achievement than that of smallpox. While smallpox was a virus, long treated and cured through inoculation and finally defeated by a massive, decades-long vaccination campaign, guinea worm disease is caused by a parasite—a living and perceptible organism—and has no known treatment or vaccination. In other words, we’ve almost conquered this foul disease by killing off a species via medical elbow grease alone.
Guinea worm disease, also known as dracunculiasis, is both bizarre and mysterious. It has afflicted humans for at least 3,500 years, but was only first seriously studied in the 1860s. Caused by drinking water containing fleas infected with guinea worm larvae, the disease takes hold as tiny worms hatch in one’s body. The worms grow for about a year, causing no pain or symptoms, until, one day, a worm, as thick as a spaghetti noodle and measuring up to four feet in length, crawls down the leg between the bone and skin, forming a massive blister. Once the blister bursts, after about 72 hours, the worm slowly emerges from the popped pustule over the course of several weeks, causing extreme burning that can only be soothed by dipping the afflicted leg in water, thus allowing the parasite to release more eggs and perpetuate its life cycle.
The disease is rarely deadly, only causing damage when people try to remove the worm all at once and kill it—it must be removed over weeks by winding it around a stick. If the body of the worm breaks, the blister wound can putrefy, leading to dangerous infections. But more importantly for developing regions where a lack of sanitation facilities helps the disease thrive, guinea worm is debilitating, knocking out entire villages for weeks, and can be contracted repeatedly as the body cannot develop a resistance. In one notable case, due to a mass outbreak of guinea worm disease, a Nigerian region lost as much as $20 million in potential earnings per year.
Photo by CDC, via Wikimedia Commons
Perhaps because it was a disease that affected the most marginal, poor people, a global eradication program didn’t emerge until 1980, led by the United States’ Center for Disease Control. But the campaign only took off in 1986, when former U.S. President Jimmy Carter and his Carter Center decided to make guinea worm their flagship cause. They operated on a low-tech basis, using principles similar to those employed in tracking down, containing, and eliminating smallpox outbreaks. Teams were sent into the hinterland to identify villages with outbreaks, to teach locals simple ways to filter their water using little more than cloth, to chemically kill the parasites in water, to recruit local volunteers to help spread general sanitation messages, as well as to minister to those infected and prevent them from contaminating the drinking water. Along with local partners, these aid workers would continue to monitor a region after the outbreak had been contained to make sure no new cases emerged. And since guinea worm is unique to humans and cannot infect other animals, the proper education and treatment could break the cycle of reproduction and fully eradicate the parasite from a region.
These low-tech solutions are appealing for their simplicity, but would have meant nothing without strong partnerships on the ground. That’s where Carter came in, not only recruiting partners from major health organizations, but also zeroing in on prominent leaders in nations susceptible to guinea worm infestation, like generals-cum-heads of state Amadou Toumani Toure of Mali and Yakubu Gowan of Nigeria. By 1995, the World Health Organization had begun officially declaring countries free of guinea worm, and by the mid-2000s the Gates Foundation joined the action, donating millions to track down and monitor the most remote cases. By 2012 the WHO announced plans to eliminate guinea worm entirely by 2020. In 2014 alone, both Ghana and Nigeria became eligible for guinea worm-free certification. The Carter Center believes up to 80 million cases have been averted to date.
The last obstacles standing between Carter and the complete eradication of the worm are bad infrastructure and local conflicts in some of these remote areas. Most of the remaining cases have emerged in Mali and South Sudan, in regions of civil strife where it’s extremely difficult to get monitors. But amazingly, in 1995, Carter actually negotiated a four-month ceasefire in the Sudanese civil war for the sole purpose of containing guinea worm outbreaks.
Given how close we’ve come to eradicating the worms, though, some have begun to question the ethics of exterminating a species, which, no matter how vicious, is part of the ecosystem. Parasite Rex author and parasite-loving science writer Carl Zimmer wrote a preemptive obituary for the pest last year, mourning the loss of potential scientific knowledge concerning the little known creature. But, he concluded, as the parasite’s ecosystem is exclusively our own bodies, it’s probably not so bad to kill them off. The New Yorker joined in the fray recently as well, publishing a piece by a parasitologist entitled “An Extinction to Celebrate,” predicting that the elimination of the disease would have no negative ramifications, but was instead promising for the growth and health of long neglected communities.
It seems now that little can stop the demise of the guinea worm. Despite past failures in preventative and behavioral change efforts, regardless of wars, and without much concern for the ethics of extinction, the numbers continue to dwindle each year. The success of such a low-tech, low-cost, and grassroots initiative ought to give us hope for our power to combat diseases in the future. Perhaps once guinea worm is gone, we can take what we’ve learned and double down on efforts to eradicate polio, and whatever lies beyond.