The World’s Last Worm: A Dreaded Disease Nears Eradication

A dreaded tropical disease is on the verge of eradication

Join Our Community of Science Lovers!

A parasite that has plagued the human race since antiquity is poised to become the second human disease after smallpox to be eradicated. “We are approaching the demise of the last guinea worm who will ever live on earth,” says former U.S. president Jimmy Carter, whose Carter Center has spearheaded the eradication effort.

Unlike polio's high-profile eradication program, the mission to eliminate guinea worm disease has largely been off the public's radar. Affecting some of the poorest and most remote communities in Africa—97 percent of cases are in South Sudan—guinea worm is a parasitic infection caused by the nematode roundworm Dracunculus medinensis. It is the only disease transmitted solely by drinking water, and humans are its only reservoir, says James Hughes, professor of medicine and public health at Emory University. The disease spreads when villagers consume water containing fleas that harbor guinea worm larvae. The larvae grow to maturity inside the human body and emerge after a year as a fully grown two- to three-foot-long worm that often exits through the leg or foot. It is an excruciatingly painful process, and individuals often immerse the limb in water to cool the burning sensation, which starts the cycle all over again.

Since 1986 groups such as the Carter Center have distributed cloth water filters to villagers and educated residents about how not to spread the infection. They have also selectively used Abate, a larvicide, to control fleas in the drinking water.

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

So far the efforts have resulted in a 99 percent reduction in infections, says Sharon Roy of the U.S. Centers for Disease Control and Prevention. In 1986 there were 3.5 million cases, as compared with only 1,060 in 2011 and a mere five as of the first few months of 2012.

COMMENT ATScientificAmerican.com/jul2012

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American