Figure 1.
Population at risk and treated in areas covered by the African Programme for Onchocerciasis Control.
Dots represent time points for which data were available; projections for 2011–2015 (shaded area) are based on the assumptions that populations continue to grow according to the latest known growth rates and that all projects scale up therapeutic coverage by 10 percentage points per year (up to a maximum coverage of 75%).
Table 1.
Size and distribution of population in APOC target areas (thousands and fraction of total).
Figure 2.
Predicted prevalence of onchocercal infection and morbidity in APOC areas from 1995 to 2015.
Please note the different scales for the y-axes in the four panels. Shaded areas represent projections for 2011–2015. A) Prevalence of infection is defined as infestation with at least one adult female worm, or alternatively, presence of detectable microfilariae in the skin. B) Prevalence of troublesome itch, caused by onchocerciasis. C) Prevalence of onchocercal visual impairment, defined as corrected visual acuity (i.e. measured with glasses on or through pinhole) of <18/60 and ≥3/60 in the better eye. D) Prevalence of onchocercal blindness, defined as corrected visual acuity (i.e. measured with glasses on or through pinhole) of <3/60 or restriction of visual field to less than 10° in the better eye.
Figure 3.
Disability-adjusted life years (DALYs) lost due to onchocerciasis from 1995 to 2015.
The total height of the bars (colored plus blank) represents the estimated number of DALYs lost in a counterfactual scenario without ivermectin mass treatment (increasing trend due to population growth). The colored part of each bar represents the estimated actual number of DALYs lost (declining trend due to ivermectin mass treatment). The blank part of each bar therefore represents the annual number of DALYs averted by ivermectin mass treatment in the total APOC population.
Table 2.
Health impact and cost of ivermectin mass treatment, 1995–2015.
Figure 4.
Sensitivity analysis for the estimated cumulative number of DALYs averted by 2015.
The multivariate sensitivity analysis (last item) consisted of 200 repeated analyses, based on 200 sets of random parameter values, which were drawn from triangular distributions with modes equal to parameter values used in the main analysis, and minimum and maximum values equal to parameter values used in the univariate sensitivity analysis (first eight items of this figure). The results of the multivariate sensitivity analysis are expressed as the 2.5 and 97.5 percentiles of results from 200 repeated analyses.