Global prevalence and epidemiological determinants of African horse sickness: A systematic review and meta-analysis

African horse sickness (AHS) is a highly fatal, vector-borne viral disease of equids with substantial economic and animal health impacts, particularly in endemic regions. Despite numerous epidemiological studies, reported prevalence estimates remain highly variable, and a comprehensive quantitative synthesis is lacking. This study aimed to systematically evaluate and synthesize the global prevalence of AHS and to identify sources of epidemiological heterogeneity. A systematic review and meta-analysis were conducted following PRISMA 2020 guidelines, with the protocol registered in the Open Science Framework. Seven databases were searched for observational studies on AHS prevalence. Study quality was assessed using the Joanna Briggs Institute checklist. Pooled estimates were calculated using a random-effects model with logit transformation. Heterogeneity, subgroup analyses, meta-regression, and publication bias were evaluated using I², τ², funnel plots, and Egger's test. All statistical analysis were performed using RStudio software version 4.4.2. Twenty-five studies conducted between 1978 and 2025 met the inclusion criteria. The overall pooled prevalence of AHS was 50.34% (95% CI: 26.95-73.58), with substantial heterogeneity (I² = 98.1%, τ² = 6.3284; p < 0.0001), and a wide prediction interval (0.50-99.51%) indicating considerable variability in prevalence across settings. Subgroup analyses revealed marked variation by host species, age of equids, geographic region, diagnostic method, season, and study period. Meta-regression analyses indicated no significant change in the temporal trend. Funnel plot asymmetry and Egger's test suggested potential publication bias. AHS remains highly prevalent and epidemiologically heterogeneous, particularly in endemic regions. Strengthened surveillance, targeted vector control, and standardized epidemiological reporting are essential to mitigate disease burden and improve global preparedness.