A mysterious disease is killing thousands of children in Uganda, Sudan and Tanzania.

The cause of the "nodding disease" is as yet unknown but it only affects children between the ages of five and 15.

Thought to be an epileptic neurological effect of the Onchocerca volvulus parasitic worm that causes Onchocerciasis or river blindness, victims suffer seizures that often start with nodding of the head, giving it its name.

Malcolm Webb reports from northern Uganda.