Fig. 4: Onchocerciasis-associated epilepsy (OAE) prevalence as a function of Onchocerca volvulus microfilarial (mf) prevalence for three values of inter-individual exposure heterogeneity.

The coloured (beaded) lines correspond to the EPIONCHO-IBM-predicted OAE prevalence. a The solid black line and shaded grey area represent, respectively, the logistic meta-regression model fitted by Pion et al.⁷ to paired epilepsy and mf prevalence data from African settings and associated 95% confidence interval⁷. b The markers and error bars showing the 95% confidence intervals, represent data (sample sizes given in ref. ⁷) for 7 countries across sub-Saharan Africa to which the meta-regression model in ref. ⁷ was fitted (CAR, Central African Republic; Uganda, two studies: Kaiser et al. (1996) and Kipp et al. (1994)⁷). The starting point of mf prevalence for each coloured line corresponds to the modelled threshold biting rate (minimum annual biting rate for onchocerciasis endemicity) for each value of the k_E parameter (~ 75; ~ 180, and ~ 350 bites/person/year, respectively, k_E = 0.2, 0.3 and 0.4). All simulations were conducted with 300 model repeats.