From a distance, President Jimmy Carter thought, it looked like a baby. Male? Female? He was too far away to tell.

The woman cradling the child was standing near the outskirts of the crowd. The former president of the United States, who had kept his campaigning days playing with babies, walked over to say hello. After a few steps, he paused.

“It wasn’t a baby she was holding,” he says. “It was her right breast … and there was a worm coming out of its nipple.”

It was the late ’80s in a tiny village in Ghana, just a handful of miles outside the capital city of Accra, and the scene wasn’t all that uncommon. Dracunculiasis, or “Guinea worm disease,” had plagued the region for decades.

The infection, which seems straight out of a horror movie, occurs when one drinks water containing a Guinea worm parasite. After breeding in the host’s abdominal region, the parasite grows into a foot-long worm over the course of a year, then emerges from the body — usually from the foot or leg. (Although, as some cases have shown, the exit path may vary.)

In 1986, there were 3.5 million cases of Guinea worm disease across Africa and parts of western Asia. Today, experts say, only 126 cases remain throughout remote regions in South Sudan, Mail, Chad and Ethiopia.

If eliminated in these four countries, Guinea worm will become the second disease in history — behind smallpox — to be completely eradicated.

There isn’t a drug or vaccine to prevent Guinea worm disease; anyone is susceptible to it. And it’s not uncommon for multiple worms to grow inside one person simultaneously. Most people living in affected areas contract the disease every year; for some, it has become routine.

The disease operates in a vicious cycle. After the worm is fully grown inside of a host, it creates a searing hot blister as it exits the body. Typically, the blister is so painful that the victim returns to water to ease the burning, which in turn reunites the worm with the water source — and the cycle repeats.

Since the mid-1980s, global health organizations, including the Carter Center (hence President Carter’s trips to Ghana), have worked with local African communities to safely remove the worms from infected victims. The key, they say, is to remove the worms using sticks — a process that can take days, even weeks, to complete — and kill the worms before they have the chance to get to water.

Those efforts, in conjunction with on-site education programs and water filtration devices, have led to the drastic reduction in cases over the years.

But the biggest challenge moving forward, says Dr. Mark Siddall, curator of the Division of Invertebrate Zoology at the American Museum of Natural History in New York City, is tracking down the remaining cases — almost all of which are in remote, off-the-beaten-path areas.

Some organizations have started using $100 incentives, in which they provide cash to anyone in previously infected villages who can point them to areas where the disease is still prevalent. For a disease to be officially eradicated, every infected country must pass a certification test by the Center for Disease Control. The CDC’s website defines “eradication” as such:

[The] permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts; intervention measures are no longer needed

The timeline for Guinea worm’s eradication, if successful, is still up in the air, but Dr. Siddall says he’s confident it will be within the next few years.

“The main thing is that we want people [to be able to] have their worms removed without going to water,” he says. “That’s the containment issue that needs to happen so that next year no one else becomes infected. We’re getting very close.”

Video produced and edited by Eric Larson. New York footage filmed by Phil Nolan. All Africa footage courtesy of the Carter Center.

The Countdown to Zero: Defeating Disease exhibit, which highlights the steps to eliminating various diseases from the planet, is currently on display at the American Museum of Natural History in New York, until July 2015.

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