In 2009, the Centers for Disease Control and Prevention (CDC) received a plea from officials in Uganda: Could the agency investigate a mysterious head-nodding disease spreading among more than 3,000 young people there? Healthy children would suddenly begin to nod their heads uncontrollably, sometimes falling into a trancelike state. The incidents seemed to be triggered by food, so eating was a struggle for the victims; some were dying of malnutrition as a result.
“We saw families lock their children in their homes or tie them to trees to prevent them from injuring themselves while the family was working,” says the CDC’s Scott Dowell, an infectious disease specialist charged with finding the cause.
Examining the children with brain scans, Dowell determined the spells were seizures like those seen in epilepsy. But what was the cause? Blood and urine tests ruled out hundreds of viruses, as well as hepatitis E, measles, heavy-metal ...
