OJURU, Uganda — Haunted by a merciless and debilitating disease that doctors cannot cure, villagers in this remote enclave in northern Uganda have turned to traditional healers like Alfred Ojara.

On a recent day, Mr. Ojara delivered a bitter elixir of water and vine root to the tiny contorted hands of Charles Okello, 12, and a line of other child patients supported delicately by their parents under the shade of a duru tree.

“Sometimes there will be decline,” he warned as he held up a plastic baggie of powder and recommended two doses a day. “All in all, if you stick to this one here, you will get improvement, no doubt.”

But when it comes to nodding disease, a mysterious ailment that has stalked the brains and nervous systems of thousands of children in this part of Africa, there is considerable doubt. It is a little-understood disease, dating back years, that stunts growth, causes mental retardation and sets off sudden seizures. No one knows what causes it, and it appears to attack only children, who lose their appetites, grow frail and slowly waste away.