What is nodding syndrome?
Imagine a syndrome so unusual that it has been reported in only one small corner of the world. Nodding syndrome may be such a condition. Nodding syndrome, also referred to as nodding disease, is characterized by a nodding behavior of the head that is accompanied by convulsions, staring spells, or other manifestations of seizures. The condition mainly affects children aged 5-15 years and has been reported in Africa, specifically in South Sudan, Northern Uganda, and southern Tanzania.
What causes nodding syndrome?
The U.S. Centers for Disease Control and Prevention (CDC) began an investigation of this unusual neurologic condition in May 2011, when CDC officials conducted a study of the illness in two different geographic locations in South Sudan. Current infection with the parasite Onchocerca volvulus (as diagnosed by skin snip biopsy) was more common in the patients with nodding syndrome than in the general population. About 73% of affected patients had onchocerciasis, compared to about 47% of nonaffected individuals. Still, no definitive reason has been identified that would correlate parasite infection with the symptoms of nodding syndrome. However, the CDC recommended the continued use of mass treatment against onchocerciasis until more is understood about this puzzling condition. In addition, the CDC plans to investigate nutritional and chemical toxins as other potential participants in or causes of this condition.
No association with other risk factors, including exposure to munitions, parents' occupations, or demographic characteristics has been identified in the children who suffered from nodding syndrome. No child has been known to recover from the condition and its exact cause and risk factors remain unknown. Further research is needed to clarify the role, if any, that infection with Onchocerca volvulus may have in the causation of this illness. Recent reports from Africa suggest valproate, an antiseizure medication, has improved some children's symptoms, but has not cured the condition. Studies are currently underway to elucidate the cause of this mysterious syndrome.
Centers for Disease Control and Prevention. "Nodding Syndrome -- South Sudan, 2011." Morbidity and Mortality Weekly Report (MMWR) 61.3 (2012): 52-54.