Published by the Financial Times.
Becoming US president from a humble farming background in rural Georgia is hard to surpass. However, the biggest achievement of Jimmy Carter, who turned 90 this month, could yet be to come.
Since 1986 – five years after he left the White House – he has been pursuing a goal arguably more ambitious than anything he did in office: the eradication of Guinea worm disease.
Nearly three decades later, success is tantalisingly near. In 1986, the disease afflicted an estimated 3.5m people a year in 21 countries in Africa and Asia. So far this year, fewer than 100 cases have been reported in four countries.
"We are so close," Mr Carter said this year. "I look forward to personally announcing that we have stopped transmission of Guinea worm disease worldwide."
Should that happen – and Mr Carter believes it will "within the next year or two" – Guinea worm disease will become only the second human disease, after smallpox, to be wiped from the face of the earth.
This would further embellish the reputation of the peanut-farmer-turned-president from Plains, Georgia, as "the best ex-president in US history". By setting up the Carter Center in Atlanta to promote global peace and health, he established a model now common among former statesmen looking for a globe-trotting political afterlife.
But whereas other former politicians such as Bill Clinton and Tony Blair have been criticised for mixing philanthropic and commercial interests, Mr Carter has taken an unshowy approach to brokering peace talks and tackling obscure diseases.
"When organising the Carter Center, I have to admit my first projected goal was to bring peace to people," he says.
"But then we began to see that the main goal . . . would be to fill vacuums in the world; that is to do things that the UN or the US government or Harvard University were not doing."
Guinea worm disease was an ideal candidate. Some academics suggest that the Bible's mention of a "plague of fiery serpents" refers to this unpleasant parasite. The infection is contracted when people drink water from ponds infested with worm's larvae.
Once inside the host, the larvae mate and mature. The female worms – which can grow up to three feet long – emerge about a year later through painful sores in the skin. The best way to soothe the pain is by submerging the affected area in water. But this triggers the worm to release her eggs, and the cycle repeats.
Although not usually fatal, the disease incapacitates people for extended periods, making them unable to care for themselves, work or attend school.
The only known treatment has been used for thousands of years: extraction of the worm by winding it around a small stick – a slow, painful process that can take weeks.
So how has this ancient scourge been brought to the brink of extinction without a medical breakthrough?
The answer could hold lessons for tackling other neglected tropical diseases. Rather than hunting for a medicine or vaccine, the Carter Center focused on community-based intervention to educate and change behaviour. This included teaching people to filter drinking water and keeping anyone with an emerging worm away from sources of drinking water.
Working with partners including the World Health Organisation and national health ministries, the Carter Center has trained thousands of local volunteers to provide grassroots support and surveillance.
Financial rewards are offered to anyone reporting a confirmed case – ensuring that most are caught quickly and prevented from spreading.
Efforts are now concentrated on the four remaining countries where the disease is present: Mali, Chad, South Sudan and Ethiopia. It would be the first parasitic disease to be eradicated, and the first disease of any kind to be eradicated without use of a vaccine or medicine.
However, nobody is taking success for granted, when just one case can lead to dozens more if the larvae are spread.
Few people understand what is at stake better than Abdullahi Rabiu, a Nigerian farmer who holds the dubious record for having the most Guinea worms emerge from his body at one time: 84. "I couldn't move because the worms were coming from so many different places," he recalls of the experience 15 years ago.
Mr Abdullahi, now 40, recovered and went on to marry and have 14 children. Others were not so lucky. "It was hard to believe that one day this disease would be gone from our communities for ever," he says. "But today, people in Nigeria are no longer crippled or disabled because of this disease. They are back to their normal business and are carrying on with their lives."
For that, Mr Abdullahi and millions of others across Africa have President Carter to thank.
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