Scientists still in the dark about nodding syndrome

A four-day international scientific meeting in the Ugandan capital, Kampala, highlighted the many unknowns of so-called "nodding disease" or "nodding syndrome", which has affected more than 3,000 people in the north of the country, with patients suffering from involuntary nodding, neurological deterioration and, in many cases, death.

Nodding syndrome was detected in the 1960s in parts of Tanzania. It also appeared in what is now South Sudan in the 1990s, but the syndrome began attracting international attention in 2011 as hundreds of cases were reported in northern Uganda, a region emerging from a decades-long conflict with the Lord’s Resistance Army.

Uganda's Ministry of Health introduced a national plan at the beginning of 2012 to treat the symptoms of the syndrome in three affected districts - Kitgum, Lamwo and Pader - including distributing anti-epileptic medication and nutritional supplements. Nodding syndrome patients generally suffer from malnutrition because food - along with cold weather - are frequent triggers of the nodding. Since the plan was announced, the syndrome has been detected in three additional northern districts - Gulu, Amuru and Oyam.

The international meeting, which ended on 1 August, was the first to bring together various actors, including the UN World Health Organization, the US Centres for Disease Control, the UK's Department for International Development and health officials from Sudan, Tanzania and Uganda.

While much remains unknown, the participants did settle on an official name - nodding syndrome - and a case definition that will help field workers in all three countries determine the extent of its spread. People with nodding syndrome (almost exclusively children under 18) exhibit at least two incidents of involuntary nodding every 5-20 minutes. They also exhibit neurological abnormalities, nodding triggered by food or cold weather, physical wasting, delayed sexual or physical development and psychiatric symptoms.

Cause unknown

That is where the definite answers stopped, though. Jane Ruth Aceng, director-general of health services at Uganda's Ministry of Health acknowledged: "We do not know the cause."

Participants were not certain if the syndrome was neurological or psychiatric, since many of the patients are living in post-conflict settings. There is also little historical information or even confirmation of all of the places where it is present. Some participants suggested the syndrome could also be in Kenya, Liberia and Cameroon.

Participants were able to settle on areas of potential research to identify the cause.

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In Uganda, attention has focused on the relationship between the syndrome and onchocerciasis (river blindness), a parasitic disease transmitted by black flies. All of the reported cases so far have occurred in sub-Saharan Africa's onchocerciasis belt. But researchers also called for investigations to determine if there was a possible relationship between the syndrome and two parasitic roundworms - mansonella streptocerca and mansonella perstans.

Initial research also indicates that Vitamin B6 deficiency, early malnutrition, fungal contamination of food and other environmental toxins could also be possible causes.

They ruled out two possible theories - exposure to munitions and the food from internally displaced camps - that have gained popular attention in Uganda. Because the disease is almost exclusively appearing in areas that were ravaged by the LRA, the affected populations have been quick to make a link between the conflict and the syndrome.

Through laboratory and epidemiological tests "we find that there is really no difference between the children who have been exposed and have gone on to develop nodding syndrome and those who have not," said James Sevjar, a neuroepidemiologist with CDC.

With a renewed, unified agenda, the international community is now looking for funding to set up studies and a systematic surveillance system across all of the affected countries. In the absence of more knowledge, they also called for more funding to determine the best way to treat the syndrome's symptoms so that patients could attempt to resume normal activities.

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