[In Depth] Parasitic worm may trigger mystery nodding syndrome
Between 1990 and 2013, thousands of children in war-torn South Sudan and northern Uganda suddenly developed a severe and puzzling form of epilepsy. When exposed to food or cold temperatures, affected children nodded their heads uncontrollably. Over time the seizures often worsened, leaving the children severely disabled. Many died of malnutrition, accidents, or secondary infections. The outbreak triggered an intense hunt for the cause, but searches for viruses, bacteria, environmental toxins, genetic factors, and nutritional deficits all came up empty. One key clue: Areas with nodding disease also had high rates of infection with the parasite Onchocerca volvulus, best known for causing so-called river blindness. Now, a study finds that the worm might trigger the body's own defenses to attack neurons. Author: Gretchen Vogel