High prevalence of epilepsy in an onchocerciasis endemic health zone in the Democratic Republic of the Congo, despite 14 years of community-directed treatment with ivermectin: A mixed-method assessment

Objectives: To investigate the reasons for the high prevalence of epilepsy (>6%) discovered in 2015 in the Aketi health zone in the north of the Democratic Republic of the Congo. Methods: Persons with epilepsy (PWE) diagnosed in a door-to-door survey in 2015 were traced and re-examined in 2017 by a neurologist. Confirmed PWE were paired with matched controls. For onchocerciasis assessment, children 7–10 years old were tested for IgG4 Onchocerca volvulus (OV16) antibodies, a rapid epidemiological mapping of onchocerciasis (REMO) study was performed, and ivermectin coverage was investigated. Results: Forty-three (61.4%) previously diagnosed PWE were traced; the neurologist confirmed the epilepsy diagnosis in all of them. The overall OV16 positivity rate was 64.5%. Poor ivermectin coverage (55.9%) and a high prevalence of onchocercal nodules (>70%) were observed. The prevalence of epilepsy was 5.7% in Aketi rural town, with nine PWE (13.8%) experiencing head nodding seizures. A case-control study showed that PWE had lower body weight and higher ivermectin coverage in 2017 than healthy controls. Conclusions: The high prevalence of epilepsy in the Aketi health zone, despite 14 years of community-directed treatment with ivermectin (CDTI), was found to be associated with high onchocerciasis transmission and low ivermectin use. An awareness programme to increase ivermectin coverage and the introduction of a bi-annual CDTI programme should be considered. Keywords: Onchocerciasis, Epilepsy, Ivermectin, Prevalence, Incidence, Case–control, Focus group discussion, Stigma