For today's Interesting Medical Fact of the Week, we're going to get a little bit Agatha Christie. I love Agatha Christie, because a) I love mysteries and b) I'm an old granny at heart. But in terms of mysterious illnesses, this one takes the biscuit.
So-called nodding disease (or nodding syndrome) was first described in the mountains of Tanzania in the 1960s. Since then, it's spread to areas in south Sudan and northern Uganda. It's an extremely serious progressive disease which only affects children, and it's almost always fatal. There is no cure. And no-one is even sure what causes the illness.
The symptoms of nodding disease include complete and permanent stunting of growth, including development in the brain, which leads to mental retardation. The name of the illness comes from the characteristic seizures suffered by affected individuals, which cause their heads to nod rapidly; the only treatment currently available for nodding syndrome is epilepsy drugs which can help to control these seizures. Extra weird is the fact that these seizures seem to happen most commonly when the child begins eating or feels cold. Children become severely malnourished because they are frequently rendered unable to eat. Many children with nodding disease actually die from falls or accidents like drowning or burning, which they're at higher risk of because of their mental impairment.
At the moment, the hypothesis that seems most likely to explain this disease suggests that it may be linked to river blindness (onchocerciasis), an illness caused by a kind of parasitic worm which is transmitted to humans through the bite of the black fly. Cases of nodding disease are concentrated in areas where there are high levels of infection with the river blindness parasite and it seems there may be a link, although no-one's yet worked out what it is. There may also be a link with low serum concentration of the blood.
There is a little bit of good news. The mysterious illness has attracted some international attention, and this week Uganda opened its first treatment centres specifically for children with nodding disease. At the moment, though, the best they can aim for is to control the illness's symptoms.