TUMANGO, Uganda Nurse Oweka Johnson pulls his goggles down onto his face and revs the engine of the motorbike, ready to roar off into the dust.

Each day Johnson drives far out into the bush of northern Uganda to provide lifesaving health care to scores of children suffering from a baffling condition known as nodding syndrome .

The neurological disorder is often ignored, as many of the thousands of children affected live in Ugandas remote north, a land at peace but struggling with the legacy of long years of civil war. Its partly because of the areas remoteness that the causes of the syndrome remain a mystery .

Though limited in its spread, nodding syndrome is devastating to the tiny communities that are affected. Scientists first recorded cases of nodding syndrome in Tanzania in the 1960s, but it is not clear whether that outbreak is related to the one in Uganda. (Neighboring South Sudan has also reported cases, but the ongoing conflict there makes the extent difficult to assess.)

Photographer Sumy Sadurni and I had come to find out more about what was behind a strange syndrome that has left thousands of children crippled and in pain. And joining Johnson on motorbikes was the only way to reach the remote farms at the end of narrow tracks.