The role ofOnchocerca volvulusin the development of epilepsy in a rural area of Tanzania

Abstract

SUMMARYIntroduction.Several reports indicate high prevalences of both onchocerciasis and epilepsy in some regions of Africa. This raises the question of whether these diseases are associated. We therefore investigated people with epilepsy and/or onchocerciasis living in an area in Tanzania endemic forOnchocerca volvulus(O. volvulus).Methods.We collected clinical information, skin snips, and blood from 300 individuals, and cerebrospinal fluid (CSF) from 197. Participants were allocated to 4 groups consisting of people with epilepsy and onchocerciasis (n=135), those with either epilepsy (n=61) or onchocerciasis only (n=35), and healthy individuals (n=69). Samples were evaluated for microfilaria, IgG4antibodies againstO. volvulus,O. volvulusantibody index (CSF/serum), and CSF routine parameters. Polymerase chain reaction (PCR) was performed on skin snips and CSF.Results.No difference was found in microfilarial density between participants with and without epilepsy (P=0·498). The antibody index was raised in 2 participants. CSF PCR was negative in all samples tested.Discussion.Our results do not give evidence of a relationship betweenO. volvulusand epilepsy. Despite the fact that 2 participants had raised antibody index, the existence of cerebral onchocerciasis caused by migration of microfilariae into the CSF appears unlikely. However, to date unexplored reactions to the infestation withO. volvuluscausing epilepsy cannot be excluded.