Jimmy Carter’s greatest victory was in the worm-killing business

Former US President Jimmy Carter is dead at the age of 100. While there are many aspects of Carter’s life that deserve attention, few can be as remarkable as his efforts to help eradicate one of the world’s most dreaded parasites, the guinea worm (Dracunculus medinensis).

Carter died at her home in Plains, Ga., on Sunday, nearly two years after she first began hospice care. Although he only served one, often much criticizedterm as the 39th President of the United States, his accomplishments extended beyond those four years. Chief among these successes is that of the Carter Center Guinea worm eradication programwho is already inches away from total victory.

Guinea worm is a parasite of such long standing that it is referenced in the Old Testament. The freshwater nematode it usually infects humans through consumption of drinking water that contains copepods—small crustaceans—which are themselves infested with worm larvae.

The larvae reach our intestines where they fully mature and mate. The males then die, and the pregnant females – which grow up to three feet (100 centimeters) long – migrate to a place under our skin, usually along our legs. About a year after infection, the females cause a blister to form. When this blister bursts, the worm slowly exits our skin, causing a painful burning sensation that prompts the infected person to cool their wound in the nearest water source. The female then releases thousands of larvae into the water, restarting the entire process.

This infection is not just unpleasant to suffer – it is often downright debilitating. The worm can take days or weeks to safely and painfully extract, during which time people cannot work or go to school. And if the worm breaks off during removal, it can cause secondary infections that can eventually lead to permanent damage.

While freshwater sanitation made Guinea worm disease less of a global problem by the end of the 20th century, about 3.5 million people still contract these infections annually in Africa and Asia in the 1980s. In 1986 Carter’s nonprofit organization, the Carter Center, launched a public health campaign to eradicate the guinea worm. And that was it a clear success. Last year, there were only 14 reported cases of Guinea worm in humans; by November there were only 7 cases in 2024

Carter and his organization don’t deserve all the credit, of course. The World Health Organization and other major groups have also played a significant role, while community leaders and residents in endemic areas have been the driving force behind eradication efforts on the ground. Since there is no vaccine or medicine for Guinea worm, the eradication campaign relies heavily on physical interventions such as durable straws that filter infected copepods from drinking water, as well as close surveillance of potential cases.

Not everything has been smooth sailing for the campaign. Guinea worm was a suitable candidate for eradication because worms rely primarily on human hosts to reach their full life cycle. For a long time we thought that only humans could act as this final link in the chain, but a decade ago it became clear that species could also mature in other animals, especially dogs. So while annual human cases have remained low in recent years, there are thousands reported annual infections in animals during the last decade.

This latest development has hampered the Guinea worm eradication schedule. Until infections in both humans and animals reach zero and remain at zero for several years, the worm can continue to exist. But health officials and communities in endemic areas are adapting. Annually reported animal cases recently dropped from 886 cases in 2023. at 448 so far this year, an indication that efforts on the ground are mitigating the parasite’s spread among animal hosts.

Jimmy Carter said in 2015 that he hoped to see Guinea worm has been completely eradicated before his death. Unfortunately, that didn’t happen. But Carter certainly left behind a monumental public health legacy that will continue long after his death.