Prevalence of Onchocerciasis Infection in the Sub-Saharan Africa Countries: A Systematic Review and Meta-analysis

Background: Findings from many African countries show that the prevalence of onchocerciasis infection is fragmented and in a wide range. Clear and organized evidence that showed the prevalence is limited. Therefore, this systematic review and meta-analysis estimated the pooled prevalence of onchocerciasis infection in the sub-Saharan African Countries. Methods: Published articles found in Scopus, PubMed/Medline, Science Direct, Google Scholar, and Cochrane Library databases were systematically searched. Based on the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was employed to determine the prevalence for onchocerciasis infection among peoples of all age groups in Africa. Observational studies from 1 January 2015 to 10 February 2021 revealed the prevalence of onchocerciasis in the sub-Saharan African countries was incorporated. The pooled prevalence of the studies was computed using STATA version 14 statistical software. The heterogeneity of the study was assessed using Cochrane Q test statistics, the I-squared values test, and the Galbraith plot. Considering within and between variability, the randomeffect model was used to determine the pooled prevalence. Funnel plot and egger’s tests were conducted to assess publication bias. Results: Out of 1985 accessed studies, 17 studies fulfilled the eligibility criteria and were included to estimate the pooled prevalence of onchocerciasis infection. The pooled prevalence of onchocerciasis was 30% (95% CI: 13, 47) in sub-Saharan Africa. Thirty-two percent (95% CI: 9, 56)) and 28% (95% CI: 2, 54) of onchocerciasis infection were identified from the study conducted before 2015 and after 2015, respectively, based on the subgroup analysis. The prevalence of onchocerciasis among farmers and housewives was 35% (95% CI: 12, 58), 18% (95% CI: 10, 27), respectively. Conclusion: Onchocerciasis is still of immense public health importance. Hence, the local government and other stakeholders should implement rigorous and comprehensive onchocerciasis prevention strategies such as improved sanitation, vector control, mass drug administration campaigns, and multifaceted methods based on their context.