Since 1986, former President Jimmy Carter has devoted his foundation, the Carter Center, to the eradication of Guinea worm, a parasitic disease transmitted in contaminated drinking water. The end is near. Only 148 cases were found in the world last year, and Dr. Donald R. Hopkins, a former director of the Centers for Disease Control and Prevention now leading the foundation’s efforts, said this year’s total should be closer to 100.

On Jan. 13, the American Museum of Natural History will open “Countdown to Zero,” a display devoted to the efforts to eradicate Guinea worm and other diseases. Mr. Carter is expected to attend the opening, according to museum officials.

Guinea worm — formally dracunculiasis, or “affliction with little dragons” in Latin — is ancient. Worms have been found in Egyptian mummies and may be, as the Bible says, the “fiery serpents” that attacked the Israelites. Dracunculiasis hovers on the brink of extinction, in line to be the second human disease ever eradicated, after smallpox.

You get it from drinking pond water. But symptoms take a year to show, when a blister of acid forms under the skin. Once that pops, the head of a pale white worm emerges — usually from a foot, but it can erupt anywhere, even eye sockets. Your instinct is to thrust your scorching limb into water. But doing so completes the worm’s life cycle, causing millions of larvae to squirt out to await the next victim.