Salmonella in African Animals and Animal-Derived Foods: A Continent-Wide Systematic Review and Meta-Analysis of Prevalence, Serovar Distribution and Antimicrobial Resistance.

BACKGROUND Salmonella remains one of the most important foodborne pathogens globally, yet its burden in African animals and animal-derived food systems has not been comprehensively quantified.

METHODS A systematic search strategy was implemented following the PRISMA guidelines. Databases such as African Journal Online, Web of Science, Scopus and PubMed were searched from their inception until May 2025. Descriptive statistics and a proportional meta-analysis utilising a random-effects model with a 95% confidence interval were employed in the data analysis.

RESULTS A total of 104 studies comprising 41,320 samples were included. The pooled prevalence of Salmonella across all sources was 16.3% (95% CI: 12.6-19.9; I2 = 93.3%). Country-level estimates ranged from 2.5% (95% CI: 1.0-5.0) in Togo to 45.4% (95% CI: 20.0-72.1) in Uganda. Subregional prevalence was highest in Central Africa at 46.5% (95% CI: 25.0-65.2). Poultry and poultry products showed the greatest burden at 18.6% (95% CI: 15.3-21.9), followed by livestock at 15.5% (95% CI: 6.5-24.5) and fish/seafood at 15.5% (95% CI: 7.2-23.9). Internal organs exhibited the highest sample-type prevalence at 24.2% (95% CI: 0.0-53.8), whereas eggs and milk showed lower rates at 7.3% and 3.1%, respectively. Among serotypes, the most prevalent were S. Heidelberg 56.4% (95% CI: 0.40-99.76), S. Infantis 22.4% (95% CI: 3.36-70.48) and S. Newport 20.6% (95% CI: 10.95-35.48). Across 14 antimicrobial classes, resistance was highest for tetracyclines at 57.3% (95% CI: 46.45-67.52), followed by sulfonamides at 49.7% (95% CI: 26.18-73.30), macrolides at 48.2% (95% CI: 22.82-74.51) and β-lactams at 37.5% (95% CI: 29.11-46.75). Resistance to third-generation cephalosporins was 25.3% (95% CI: 17.73-34.74) and to fluoroquinolones 22.1% (95% CI: 12.95-35.12). The pooled prevalence of multidrug-resistant isolates was 43.7% (95% CI: 28.1-59.2).

CONCLUSION These findings indicate that Salmonella contamination and resistance are widespread across African animal-source food systems and show the urgent need for coordinated One Health surveillance, strengthened biosecurity and antimicrobial stewardship across the continent.