Nodding syndrome, a disease that has sickened more than a thousand children in northern Uganda since the summer, is named for its most distinctive symptom: involuntary, at times violent bobbing of the head, like someone repeatedly nodding yes or snapping out of a doze. Outbreaks of nodding syndrome cropped up in South Sudan this summer, in the same region of Uganda two years ago, in southern Sudan---not yet an independent nation---in 2001, and periodically in remote mountain villages in Tanzania. Nearly half a century has passed since the first reported case, but epidemiologists still have only a rudimentary understanding of this mysterious disease. They've found few hints as to what might cause it, and no effective treatments. The diseases strikes otherwise healthy children, usually between ages 5 and 15. The children first have trouble concentrating; soon, the characteristic head-nodding, often triggered by eating or the sight of food, begins. As the disease progresses, it stunts growth and leads to physical disabilities and cognitive decline. The prognosis only gets worse from there: pediatrician Jennifer Foltz, an Epidemic Intelligence Service Officer who tracked the 2009 Ugandan outbreak, says in a CDC video about the condition, "We haven't had any reports that anybody's improved and gotten better from this disease, and we have gotten reports that children have passed away from the disease." Scott Dowell, another CDC investigator, had an even bleaker take. "Once they have it, they are going to die with it, and much earlier than they would have otherwise," he told Nature News. Recent investigations have yielded some clues. Epidemiologists now know that the syndrome is a new seizure disorder, with seizures that, among other effects, cause the neck to momentarily lose muscle tone, triggering a head bob. Brain imaging studies have uncovered signs of neural degeneration. Some researchers have suggested that
the parasitic worm that causes river blindness, might be linked to nodding syndrome as well---but what the parasite's role in the disease is, exactly, remains a mystery. So, too, does how to treat the condition. Read more at Nature News.