Human Filariasis in Africa (2000–2025): Changing epidemiology, uneven diagnostic progress, and persistent neglect

BACKGROUND: Human filariases remain a major group of neglected tropical diseases (NTDs) in Africa. Despite large-scale control strategies and availability of effective drugs, persistent and re-emerging infections indicate gaps in surveillance and diagnostic capacity. Over the past two decades, diagnostic technologies and elimination programs have evolved, yet no synthesis has assessed how these changes affected research output and prevalence estimates across the continent. The objective of this study was to systematically review and synthesize population-based studies on human filariases in Africa from 2000 to 2025, examining temporal trends, diagnostic methods, and prevalence patterns across species and regions. METHODS: A systematic review compliant with PRISMA 2020 was conducted for studies published between January 2000 and October 2025 in PubMed, Scopus, ScienceDirect and African Index Medicus. We included population-based studies reporting prevalence of human filariases using confirmatory diagnostics. Data extraction included study characteristics, diagnostic method and prevalence estimate. Study quality was evaluated using the Newcastle-Ottawa Scale. RESULTS: A total of 180 studies from 31 African countries were included. Research activity peaked in 2011-2015 and then declined. Microscopy remained the dominant diagnostic method throughout the 25-year period, although serology and molecular tools increased after 2011. A consistent reduction in prevalence was observed for lymphatic filariasis and onchocerciasis in settings with mass drug administration (MDA). Mansonellosis and loiasis showed no comparable decline and were frequently detected incidentally, reflecting limited diagnostic oversight and the absence of targeted elimination programs. CONCLUSIONS: Long-term MDA programs are associated with reduced prevalence of lymphatic filariasis and onchocerciasis. Loiasis shows a increasing and unstable trend, influenced by diagnostic method and lack of targeted interventions. Mansonellosis remains neglected, underdiagnosed, and largely unmonitored. Strengthening local diagnostic capacity and integrating filariasis screening into existing platforms (e.g., malaria programs) may prevent silent transmission and resurgence in areas declared free of infection.