Persistence of Onchocerciasis infection after decades of mass drug administration in the Western North Region of Ghana

Abstract

Introduction Onchocerciasis, a neglected tropical disease caused by Onchocerca volvulus, remains a significant public health concern in endemic regions despite decades of mass drug administration (MDA) with ivermectin (IVM). This study evaluates the impact of IVM MDA on onchocerciasis transmission in the Sefwi Akontombra district of Ghana and identifies factors contributing to the persistence of the infection. Methodology A cross-sectional study was conducted across 25 communities in the district. Participants were clinically examined for palpable onchocercomata, and compliance with IVM treatment was assessed through structured interviews and community health records. Participants with one or more palpable sub-cutaneous nodule had skin snips taken from the iliac crests for microfilariae assessment. Data were analysed using descriptive statistics, chi-square tests, and logistic regression models. Results Of the 1,980 participants assessed, 35.4% had subcutaneous nodules, with variations in prevalence across communities. The district community microfilariae load (CMFL) and geometric mean intensity were 0.25 MF/ss and 0.26 MF/ss respectively. Age, MDA compliance and gender were the independent predictive factors significantly associated with onchocerciasis in the district. Conclusion While MDA has reduced onchocerciasis prevalence, transmission persists. To accelerate elimination efforts, targeted interventions should focus on increasing MDA compliance through intensified community engagement, integrating alternative treatment strategies such as anti-Wolbachia therapy, and adopting more sensitive diagnostic tools for improved surveillance.