[Onchocerciasis and epilepsy. Epidemiological survey in Mali]

Abstract

A door-to-door survey was conducted in 18 villages in Mali with a total of 5,243 inhabitants classified according to the endemicity of onchocerciasis. Each epileptic was matched with two controls. The survey protocol included the following steps in cases and controls: census taking, socioeconomic data, screening for epilepsy, clinical examination, laboratory testing to detect parasites in stools and urine, and snip-test. The crude prevalence of epilepsy was 13.35 per 1,000 (n = 70). Epidemiological study provided a number of valuable demographic insights concerning age at onset, type of seizure activity during seizure and personal and family medical history. A transverse study showed that the prevalence of epilepsy was not significantly higher (p = 9.09) in zones of high endemicity of onchocerciasis (16.1 per 1000) than in zones of low endemicity (10.8 per 1000). Case-control findings showed evidence of onchocerciasis in 22.4 p. 100 of epileptics and 21.7 p. 100 of controls (odds ratio = 1.02 IC 95 p. 100: 0.4-2.19, not significant). Various risk factors including genetic factors and low socio-economic status could explain the trend toward a higher incidence of epilepsy as well as higher morbidity rates in zones of high endemicity of onchocerciasis.