Factors influencing vector control for onchocerciasis in Sub-Saharan Africa: A systematic review

Abstract

Onchocerciasis, commonly known as river blindness, remains a significant public health challenge in Sub-Saharan Africa, where the blackfly serves as its primary vector. This review synthesizes evidence on the factors influencing vector control programs in the region. A search was conducted in the Cochrane Library, PubMed, Web of Science, and Scopus to identify factors which influence the successful implementation of vector control programs in sub-Saharan Africa, covering studies published between 1 January 2000 and 31 March 2025, including both experimental and quasi-experimental designs. Study selection was conducted by two reviewers using Rayyan software, disagreements resolved by a third reviewer. Quality appraisal was assessed with JBI critical appraisal checklist. Findings were synthesized thematically and narrated. Seventeen studies were included in this review. The review identified several key determinants affecting vector control. Financial constraints were a major barrier, with high start-up and maintenance costs limiting the sustainability of larviciding programs. Community-based interventions, such as the 'slash and clear' method of removing trailing vegetation, were cost-effective but required consistent local commitment. Improper application of larvicides and the emergence of insecticide resistance posed additional challenges, as did environmental factors such as high rainfall and fast river currents, which affected breeding site accessibility and intervention efficacy. The success of vector control programs for onchocerciasis in Sub-Saharan Africa is influenced by several factors which requires enhanced investment, community engagement, and technical capacity building for the long-term success of onchocerciasis elimination efforts in the region.