SUMMARY

Recent studies have suggested a possible relationship between onchocerciasis and epileptic seizures. In 1996, we identified 344 epileptics in the North Western region of Central African Republic in the Ngaoundaye sub-prefecture (44100 persons). The prevalence of epilepsy was therefore 10.9%o. This prevalence varied positively with the onchocerciasis association between onchocerciasis and epilepsy. However this survey was subjected to biases and other studies are needed to confirm this results.

Keywords: Africa, Central African Republic, Epilepsy, Onchocerciasis

RESUME

Des études recentes ont suggére une relation possible entre l’onchocercose et la survenue de crises épileptiques. En 1996, 344 épileptiques ont été identifiés dans la région Nord-Ouest de la République Centrafricaine, dans la sous-préfecture de Ngaoundaye (44.l00 personnes). La prévalence de l’épilepsie etait par conséquent de 0,9%o habitants. Cette prévalence variait positivement avec le niveau d’endémicite onchocerquienne dans les villages (r=0,73 ; p<0,001). Ces résultats descriptifs sont en favour d'une association entre l'onchocercose et l'épilepsie. Toutefois cette étude était sujette à des biais et d'autres études sont nécessaires afin de confirmer ces resultats. Mots clés : Afrique, Onchocercose, Epilepsie, République Centraficaine

INTRODUCTION

Recent studies done in Uganda(1) and Burundi (2), have suggested a possible relationship between onchocerciasis, a dermal cutaneous filariasis causing river blindness, and epileptic seizures. However, this relationship was not found in a study done by our team in Burkina-Faso3 in an onchocerciasis hypoendemic region. Certain authors indicated the need for further investigations4, ln l996,a census carried out by health agents in 40 villages in the Ngaoundaye sub-prefecture of 44 100 persons, in the North Western region endemic for onchocerciasis of Central African Republic, identified as well, people with epilepsy in the region.
The onchocercal endemicity in each village was estimated before ivermectin mass treatment Campaign, using a rapid screening technique5. The mean distance from the nearest neighbouring river was estimated for each village. In total, 344epileptics were found and the prevalence of epilepsy was 10.9%. This prevalence varied positively with the onchocerciasis endemicity in the village.

A positive correlation between the onchocercal endemicity and the prevalence of epilepsy (r=0.73; p<0.001) and a negative correlation between epilepsy prevalence and the mean distance of the villages from the nearest river (r=-0.34; p<0.03) were evident. These descriptive results are in favour of an association between onchocerciasis and epilepsy. This study has certain biases: the number of epilepsy cases was probably underestimated, however, this underestimation was uniform among areas of different onchocerciasis endemicities; distances were estimated but not accurate measurements; endemicities were assessed using a rapid method on a community basis and not on individuals; the analytical method was cross-sectional which does not eliminate other confounding factors. Despite all these limitations, these results seem particularly interesting and indicate to set up a detailed study in this country, with epilepsy being confirmed by a neurologist and onchocerciasis confirmed by skin biopsies. Table: Prevalence of epilepsy and mean distance from the nearest river according to onchocerciasis endemicity. Central African Republic, 1996

Onchocerciasis endemicity