Dynamics of Onchocerca volvulus viability and fertility through multiple rounds of ivermectin treatment. Each panel depicts either the percentage of live female O. volvulus (panels A and B) or the percentage of fertile (live) female O. volvulus (panels C and D) exposed to ivermectin treatments given annually (panels A and C) or 3-monthly (panels B and D) at standard (150 µg/kg) and high doses (800 µg/kg). The thick gray and black solid lines indicate, respectively, the marginal mean (averaged across all hosts) dynamics for standard or high-dose regimens. The thin gray lines indicate the individual host dynamics mediated by the estimated random effects terms within the statistical model (see Supplementary Materials for statistical details). For clarity, no graphical distinction is given among individual hosts given either standard or high-dose regimens. In each panel, the triangular and circular markers denote, respectively, the observed percentages of live or fertile (live) females extracted from participants given either standard or high-dose regimens. Vertical error bars denote 95% confidence intervals that were calculated using a nonparametric weighted bootstrapping procedure to account for the variable number of female O. volvulus extracted from each host. Horizontal error bars (often narrower than the data point) indicate the range of nodulectomy dates at each sampling round.