Mysterious nodding syndrome spreading through Uganda

from New Scientist
by Curtis Abraham

Large areas of northern Uganda are experiencing an outbreak of nodding syndrome, a mysterious disease that causes young children and adolescents to nod violently when they eat food. The disease, which may be an unusual form of epilepsy, could be linked to the parasitic worm responsible for river blindness, a condition that affects some 18 million people, most of them in Africa.

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.

There is no known cure for nodding syndrome, so Uganda's Ministry of Health has begun using anticonvulsants such as sodium valproate to treat its signs and symptoms. Meanwhile the disease is continuing to spread, say Janet Oola, Pader's health officer, and Sam William Oyet, the district's medical entomology officer.

It has now reached the Ugandan district of Yumbe, which borders the Republic of South Sudan – and cases have also been reported in the southern region of the world's newest country. Since gaining independence from the rest of Sudan in July, South Sudan has remained on track to eradicate one of humanity's oldest diseases – guinea worm. It is unclear, though, whether foreign aid for the new country could help prevent the spread of nodding syndrome.