The “Nodding Disease Syndrome” (NDS) is devastating to the affected people, their families and the communities where it exists. So far it kills all who get it and these happen to be mostly children and adolescents aged between 10 and 19 years.
The failure to find a cause to the syndrome or to its mode of transmission is a big challenge to the Health ministry, the government and to all scientists and experts, including local and international epidemiologists and anthropologists.
We are informed that a joint team of experts from the US Centers for Disease Control, the World Health Organisation, Mulago National Referral Hospital and Makerere University comprehensively studied NDS in 2009, six years after a similar syndrome had been reported in Lui, South Sudan.
The first big question is whether the two similar diseases occurred separately or whether the one in South Sudan crossed the border into Uganda and how this happened.
We are informed that the current outbreaks of the disease are concentrated in Kitgum, Pader and Lamwo districts, with more than 1,000 cases having been diagnosed in Kitgum alone between August and mid-December 2011. Total cases now number around 3,000 with about 200 deaths. There are also reports that the disease has reached Yumbe District, indicating that it is spreading.
First things first
The important questions scientists and other experts need to answer urgently are: What causes NDS? How is it transmitted? Can it be controlled so that it does not affect more people and spread to other areas?
At the moment, the available information is speculative, presumptive and based on suspicion without any proven scientific evidence.
The clinical medicine specialists have done an excellent job telling us in some detail the signs and symptoms of the NDS. We are told how the patient gets gripped by a series of seizures which force the patient’s neck to arch forward, then down and then up again, which looks as if someone is forcing the chin down onto the chest. And it is this movement that has caused the disease to be labelled the “Nodding Disease”.
It has been intriguingly observed that seizures normally occur when the affected person starts to eat or when the surroundings are cold. The seizures also seem to be triggered by the patient looking at and eating familiar food such as sorghum or millet, but not by looking at or eating unfamiliar food, like a bar of chocolate. The nodding starts almost immediately the food is supplied and stops when one finishes eating. There is also drooling of saliva during the attack.
What makes this disease to be considered a syndrome are the other signs which include mental retardation, stunted physical growth, malnutrition in many cases, and dehydration.
Some homes have more than one affected person raising the question of whether there is a transmittable agent causing the syndrome, and increasing the urgency of the need to find out the exact cause and mode of its transmission.
There are several hypotheses that have been advanced as to the causes of the NDS, but so far, there is again no conclusive scientific evidence to support any of them. They include the following:
The parasitic worm Onchocerca volvulus, which is responsible for causing river llindness. But the big question is how this worm, which affects about 18 million people worldwide, mostly in Africa, and is common in many places does not cause the NDS in these other places.
Secondly, although the worm is also known to infest all the three affected districts in Uganda, what must be triggering the worm to cause the NDS in these districts and not anywhere else where it occurs, if it really contributes to the causation of the disease.
All the children with NDS are said to live near permanent rivers. Could there be another agent within these rivers causing the NDS, other than the worm?
Other people tend to blame the war against the Lord’s Resistance Army rebels but we are told that toxicology reports have ruled out anything connected with this as a cause.
The 2009 Experts’ Survey found out that over 83 per cent of the cases found were suspected to have eaten Bush Meat and there is suspicion that this could have contributed to causing the NDS.
Although cross-species transmission of disease-causing agents like Prion, seem to be limited by an apparent Species Barrier, the epidemic of the Mad Cow Disease, also known as the Bovine Spongiform Encephalopathy (BSE) in the United Kingdom and its transmission to humans tends to eliminate this limitation and shows how these agents can also pose a significant public risk.