Scientific research on OAE and Nodding syndrome
There is a high prevalence and incidence of epilepsy in many onchocerciasis endemic regions where onchocerciasis is insufficiently controlled. NSETHIO collaborators recently performed door to door studies in villages close the blackfly breeding sites in the Democratic Republic of the Congo, Cameroon, Tanzania, Uganda, and South Sudan. In these villages the prevalence of epilepsy was found to be between 2 and 8%. This is much higher than the median epilepsy prevalence in non-onchocerciasis endemic regions in Africa, which estimated to be 1.4%. Therefore, at least 1% of the excess epilepsy in onchocerciasis endemic regions is probably triggered by the Onchocerca volvulus parasite.
These studies also showed that Nodding syndrome should be considered as only one of the clinical manifestations of onchocerciasis-associated epilepsy (river epilepsy) and that river epilepsy is an important neglected public health problem.
Prof. Colebunders and his team hope to finally discover the cause of river epilepsy, and to detect an effective control strategy to decrease the incidence of epilepsy in onchocerciasis endemic areas. They endeavor to contribute to the establishment of the burden of disease caused by OAE, to an internationally accepted case definition of OAE and to the creation of an international alliance to seriously address the important neglected public health problem caused by OAE.
UAntwerp researcher finds cause of mysterious nodding disease
River blindness is the root cause, and nodding disease can easily be controlled by administering an anti-parasitic drug and exterminating the blackfly.
For several years now, researchers from the University of Antwerp have been collaborating with African scientists to investigate the causes of 'nodding disease', a mysterious form of epilepsy that only affects children on the African continent. Dr Joseph Nelson Siewe Fodjo, a researcher from Cameroon, has now discovered that river blindness is the root cause, and that nodding disease can easily be controlled by administering the anti-parasitic drug ivermectin and exterminating the blackfly.
Some 50 million people worldwide suffer from epilepsy and around 80% of them live in low- and middle-income countries, often in areas of Africa where river blindness occurs. The reason for this was unknown until recently, when Dr Joseph Nelson Siewe Fodjo, from Cameroon, investigated the correlation between river blindness and epilepsy during his PhD research under the supervision of Professor Bob Colebunders as part of a project funded by the European Community.
"The study confirmed the high incidence of epilepsy in areas where river blindness is not under control, such as Cameroon, the Democratic Republic of Congo and South Sudan. In some villages, up to 6% of the population had it," says Dr Siewe. "We discovered various forms of epilepsy associated with river blindness: mainly epilepsy with generalised seizures, but also nodding disease and Nakalanga syndrome, which is associated with severe growth retardation, retarded sexual development, cognitive disorders and sometimes bone deformities."
"We saw otherwise healthy children between the ages of 8 and 12 suddenly develop epileptic seizures. This often occurred in several children in the same family. The affected families usually lived close to breeding sites of the blackfly, the transmitter of the worm that causes river blindness. As many of them cannot afford treatment with anti-epileptic medication, people with epilepsy in these areas rarely live past the age of 30."
However, according to Dr Siewe, there is a simple remedy. "This form of epilepsy is perfectly preventable, simply by distributing ivermectin – a drug that cures river blindness – annually to the entire population. Twice a year would be even better, especially in combination with efforts to destroy the breeding grounds of the blackfly and eradicate river blindness altogether."
Further research is needed to find out exactly how the worm causes the brain damage that leads to nodding disease and other forms of epilepsy. "But in any case, there is an urgent need to step up efforts to alleviate – and hopefully even prevent completely – the immense suffering of families with children with epilepsy in many regions of Africa," concludes Professor Colebunders.