"Nodding syndrome" is a poorly-understood disease that causes children and teens to nod violently, as if having a seizure, when in the presence of food or when they get cold. Likened to epilepsy because of its effects, the disease is thought to be related to parasitic worms that also cause river blindness. First discovered in the Sudan in the 1980s, a new outbreak of nodding syndrome is sweeping across Uganda, and could spread elsewhere too.

New Scientist reports:

The current outbreaks are concentrated in the districts of Kitgum, Pader and Gulu. In Pader alone, 66 children and teenagers have died. More than 1000 cases were diagnosed between August and mid-December.

Onchocerca volvulus, a nematode worm that causes river blindness, is known to infest all three affected districts. Nearly all the children with nodding syndrome are thought to live near permanent rivers, another hint of a connection with river blindness.

The link is not clear cut, though. "We know that [Onchocerca volvulus] is involved in some way, but it is a little puzzling because [the worm] is fairly common in areas that do not have nodding disease," says Scott Dowell, who researches paediatric infectious diseases and is lead investigator into nodding syndrome with the US Centers for Disease Control and Prevention.

Nodding syndrome can cause severe neurological damage, and there are reports that it can stunt the growth of its young victims. There is currently no known cure, and doctors are trying to fight the symptoms with anticonvulsants.