Impact of annual community-directed treatment with ivermectin on the incidence of epilepsy in Mvolo, a two-year prospective study

This slower change is attributed to the ability of adult worms to produce microfilariae for over a decade, even in the absence of ongoing transmission [16], and the den- sity-dependent processes that govern the lifecycle of the parasite [17]. [...] 3.3 Prevalence of epilepsy in 2020 and 2022 In the surveys conducted in 2020 and 2022, respectively, 815 of 15,755 individuals and 677 of 15,092 individuals with suspected epilepsy were referred to a physician for confirmation (Table 3). [...] A strength of the study was the consistency in the methodology and the retention of some research team members across surveys in Mvolo, Maridi and Mahenge, contributing to the reliability of the findings and integrated analysis. [...] To address the poten- tial bias of overlooking newly developed epilepsy cases in the incidence calculations, the 2022 survey was used retrospectively to calculate the incidence for the year preceding the 2020 sur- vey, and newly diagnosed epilepsy cases reported between 2022 and 2021 were excluded from the incidence rate calculations to prevent underestimation. [...] Concerning the latter, while there is a potential for recall bias as coverage data were assessed eight and ten months after the last treatment round in 2019 and 2021, respectively, the high endemicity of onchocerciasis in Mvolo, the community’s awareness of the condition, which was targeted by an awareness campaign in 2020 [41], and the need for preventive treatment may help minimise this bias.