What you need to know:
Unwrapping the mystery. Amid the blame-game and head-scratching over the mysterious disease that continues to kill hundreds, Professor George B Kirya, the former head of the Department of Medical Microbiology and Virology at Makerere University, offers an insight.
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.
So, this is not a far-fetched suspicion to warrant being investigated. The connection could also be due to some other disease-causing agent, other than the Prion, from these Bush animals.
There has been suspicion of the disease coming from infected monkey flesh.
Of recent, there has been suspicion of this being due to an epileptic epidemic. But as we know, epilepsy is not contagious, being transmitted from person to person, as the case seems to be with the NDS. We, therefore, need to find what could be triggering this epileptic-type of seizures in the affected districts, if we are to continue with the epilepsy hypothesis.
Low Vitamin B6 in the blood has also been mentioned as a possible cause.
There is so far no known cure for the NDS. Treatment being given is therefore supportive, palliative and is treating the signs and symptoms presented by the patient. This is most welcome, in the sense that much as it is not a cure and the end result is known to be death, this inevitable death should come with dignity and with little suffering to the patient.
There is what is known as a “slow virus infection of the brain”. These slow viral nervous system infections are divided into those due to conventional viruses, like measles and rubella, and are detectable in the patient and also cause immunological changes in blood and brain fluids.
The virus can also be isolated from the central nervous system fluid of the patients. It is very unlikely that the NDS we are experiencing is caused by any of these slow virus diseases.
Then there is another group of infections due to what are known as unconventional agents, whose viral nature has not yet been fully established, and they do not cause any immunological changes in the patient’s blood or other body fluids.
Among the unconventional agents that cause the slow virus infection of the brain are kuru, creutzfeldt-Jakob-disease, Gerstmann-Straussler-Scheinker, all causing diseases in man. These infections are caused by unconventional agents called prion protein.
The prion is a small protein-like infectious particle which is resistant to inactivation by most procedures, including heat, that normally modify other living cells and viruses. They do not show any abnormalities in the blood or the fluids in the brain. The disease changes by these agents that are limited only to the brain. They can, however, be transferred to chimpanzees and monkeys.
Once the brain disease is established, it progresses slowly over months or years and the person finally dies. These unconventional infectious agents do not give any detectable immune response in the infected person at all.
It is being reported that the numerous tests that were carried out in the USA did not reveal much about the disease, according to Dr Scott Dowell, the specialist from CDC.
One good example of the slow virus disease is kuru, a name derived from a term in the fore language of the eastern highlanders of Papua, New Guinea, which means “to shake from fear.”
Kuru was spread in Papua New Guinea through cannibalism, where the then native custom, dictated that bone marrow, the intestines and brain be cooked and eaten following deaths of family members - with the female relatives usually consuming the brain, which was the most infected organ. The disease mostly affected women and children of both sexes and rarely affected men.
After discovering the cause and the mode of transmission of the fatal disease kuru, the prohibition of cannibalism in the 50s led to the decline in the epidemic, although the disease has persisted in very small numbers of people because of an incubation period that sometimes exceeded 50 years.
It is all well and good to continue providing good supportive palliative and symptomatic care and treatment to patients with the NDS - has been reported that a number of “Treatment Centres” have been set up and health workers are being trained on how to best treat and handle the signs and symptoms of these patients.
It is, however, very important to remind ourselves that this is not a cure to NDS. More new cases are likely to continue emerging, more people will continue dying and, may be, the disease may spread to other areas so far not yet affected, until we are able to establish the cause of the NDS, its mode of transmission and the possible control of the disease, like it happened with kuru.
This is why it is absolutely important that, as we continue providing the palliative and symptomatic treatment to the sick, we do not lose sight of doing everything possible to deal with the NDS.
This is the time when we may need to “move out of the box” and start looking at different causes of this new rare disease, outside the known and now suspected causes.
It is, therefore, high time that we sounded an international alarm to our development partners and the international scientific and health financing community to help find some answers.
We need to build a strong national and international team of experts and scientists to thoroughly study this new disease. This team should include neuro-pathologists, general pathologists, immunologists, microbiologists, zoologists, epidemiologists and others.
The Ministry of Health needs to establish very strong and carefully selected collaborative scientific centres anywhere in the world, where work of all types on this research can be carried out without much hindrance.
This study needs a special budget of its own, not that from the Ministry of Health, which after all, is insufficient to run even the usual health services. This needs to be taken as a national emergency project.
Lastly, it is very possible that NDS is one of the conditions caused by a slow brain infective-type of agent, not necessarily a virus or virus-like agent but one that behaves in a similar manner.
It is known that currently, there is no diagnostic test on blood or other body tissue-fluids for such brain-disease-causing agents. The only way to get to a diagnosis of such diseases is through either a brain biopsy, which is restrictive, or carrying out a post-mortem and carefully studying the brain parts by various experts.
Apparently, it is the general culture among the people in the districts affected by NDS not to accept the dead to be subjected to post-mortem examination.
In case there has been any post-mortem carried out so far, it will be necessary to make sure that special expert post-mortem examinations are carried out on as many patients who die from NDS as possible, if we are to get to the root-cause of this disease.
Once the causative agent is identified other experts will find it easy to build the full picture, including control, of this syndrome. Those who have lost their loved ones need to be encouraged and supported to be willing to allow post-mortems to try and save those still alive.
It took close to 25 years for researchers in Papua, New Guinea to solve the kuru riddle, and discover the cause and how the disease is transmitted, through carrying out careful, collaborative post-mortem and epidemiological studies, among other studies, which eventually led to the disease’s control.
It does not have to take us that long but we have to start somewhere – and start quickly.