Jimmy Carter's successful war against tropical diseases

One of the most exclusive clubs on Earth is that of living ex-U.S. presidents. The gang of four – Jimmy Carter, George Bush Sr., Bill Clinton and George W. Bush – spend their retirement years hitting the links, building presidential libraries, giving $100,000 speeches, writing autobiographies and doing humanitarian work.

But it is Mr. Carter, president from 1977-81, who has carved out the most fascinating and underappreciated legacy. When he founded the Carter Center shortly after his humiliating defeat by Ronald Reagan, the former peanut farmer was determined to use his fame and (very modest) fortune "to take on projects that others didn't want to address."

While he has made his mark as a U.S. envoy – official and unofficial – there is one project that makes him proudest, he told the Association of Health Care Journalists conference in Atlanta this past weekend: the eradication of guinea worm disease.

He called it an obsession. And, now, a quarter century into the quiet crusade, he is a hair's breadth from victory. "My goal now is to outlive the parasite," the 87-year-old Mr. Carter said, flashing his legendary smile.

Dracunculiasis – better known as guinea worm disease – is a millennia-old affliction that is contracted by drinking water contaminated with microscopic water fleas. The fleas carry worm larvae that settle in the body and hatch. The worms, which grow to a metre in length, burrow through the skin, causing excruciating joint pain, disfiguring lesions and often permanent disability.

The worms are so dreaded they are known as fire serpents.

Guinea Worm Disease is one of a family of neglected tropical diseases that affect the poorest of the poor. The Carter Center is also working on reducing the burden of five other NTDs aside from guinea worm:

* Onchocerciasis (river blindness): a parasitic worm disease, contracted from the bite of a black fly. It causes blindness and itching so unbearable that many sufferers commit suicide.

* Trachoma: a bacterial infection that causes the eyelashes to grow inward, causing irritation of the cornea, intense pain and blindness.

* Schistosomiasis (snail fever): contracted through contact with contaminated water housing the larvae of the parasitic flatworm, the infection damages internal organs like the bladder, kidneys and colon.

* Lymphatic filariasis (elephantiasis): a parasitic worm that lodges in the lymphatic system causing gross swelling of body parts like the arms and legs.

* Malaria: a potentially fatal blood disease caused by a parasite that is transmitted to human and animal hosts by the Anopheles mosquito; it can largely be prevented by the use of bed nets.

Many of these problems overlap. So, while promoting the filtering of drinking water, the group will also distribute mosquito bed nets and build latrines.

Mr. Carter, who negotiated a peace treaty between Israel and Egypt, said he has made more concrete and lasting contributions in his post-presidential years by working with his hands. "I am the most famous latrine builder on earth," he joked.

It is in the field of guinea worm disease that Mr. Carter has had the greatest impact. In human history, only one disease has been eradicated – smallpox. The high-profile push to eradicate polio is maddeningly close. But the eradication of dracunculiasis, done far from the limelight, is imminent.

When the guinea-worm campaign began in 1986, there were more than 3.5 million cases, concentrated in 20 countries. It is not a big killer, but it is disabling. It causes ulcers, usually in the lower legs, that grow to the size of a tennis ball, then burst, releasing the spaghetti-like parasitic worm.

The disease is confined to the poorest communities, those that tend to be at the end of the road, with little or no access to safe drinking water.

What that means, generally, is that water is drawn from ponds or puddles, and the source of drinking water is often used for bathing and toileting.

The disease is extremely painful – it feels like hot coals under the skin – and sufferers immerse their bodies in water to seek relief. The water acts as a trigger for the worm to release more larvae, which perpetuates the disease.

Staff and volunteers from the Carter Center have visited every one of the 26,500 villages where guinea worm was identified.

There, they do education work, showing villagers how to filter their water with crude strainers. They use cheesecloth, sometimes copper filters (provided by a charity) or even bed nets (if they're not treated with insecticide). The process does not magically make the water safe, but it does remove the water fleas and their larvae.

The volunteers also treat sufferers. There is no drug treatment. Instead, they have to draw out the worm and then slowly pull it out, wrapping it around a small stick over a period of weeks. It is slow, painstaking work, but it has paid off.

They are also told to keep out of water so they don't spread the larva to others.

In 2011, there were 1,060 cases of guinea worm disease identified in the world, in four countries.

Virtually all of the cases were found in a single country, with 1,030 reported in South Sudan – perhaps the most miserable, war-ridden place in the world. The other cases of guinea worm occurred in Mali (12), Chad (10) and Ethiopia (8).

Mr. Carter is hands-on, visiting these countries and affected villages himself. Having a U.S. president visit is a big deal for despots and democrats alike, and he exploits that fact. "I don't want a state banquet, I want action," Mr. Carter said.

His approach is to negotiate directly with kings, presidents and rebel leaders, to get them to sign contracts. In South Sudan, he negotiated a temporary peace treaty to allow health workers to concentrate on guinea-worm eradication.

The key to his success, Mr. Carter said, is to be self-effacing, to allow the leaders to take credit themselves when the disease is wiped out.

It is perhaps the ultimate irony that, in making the forgotten disease of forgotten people his cause, Mr. Carter's contribution has been largely forgotten.