Work

Currency as a mobile environmental reservoir of bacterial pathogens in Africa: a systematic review and meta-analysis

Year: 2026

Type: review

Study designs: Systematic Review, Meta-Analysis

Abstract: Background Circulating currency is among the most frequently handled objects in daily life and may facilitate microbial transfer between individuals, food products and environmental surfaces. Although bacterial contamination of currency has been documented across Africa, the overall burden and epidemiological significance of this contamination have not been systematically quantified. This systematic review and meta-analysis synthesized available evidence on bacterial contamination of circulating currency in Africa. Methods PubMed, Scopus, Web of Science, African Journals Online (AJOL), Google Scholar were systematically searched. Studies investigating bacterial contamination of circulating currency notes in African countries were eligible. Random-effects meta-analysis was performed to estimate pooled contamination prevalence and organism-specific prevalence while narrative synthesis was used for outcomes unsuitable for quantitative pooling. Results Forty-six studies met the inclusion criteria and contributed to the systematic and narrative synthesis. Of these, 12 studies involving 2,003 currency notes provided sufficient comparable data for the meta-analysis of overall bacterial contamination prevalence. The pooled bacterial contamination prevalence was 79.3% (95% CI: 60.9–90.4%). Organism-specific analyses showed that Staphylococcus aureus accounted for 31.2% (95% CI: 24.7–38.4%) and Escherichia coli for 24.0% (95% CI: 17.8–31.5%) of bacterial isolates recovered from contaminated currency. Narrative evidence additionally identified Klebsiella , Salmonella , Pseudomonas , Proteus , and Shigella species among frequently reported contaminants. Several studies also documented multidrug-resistant, extensively drug-resistant, and pan drug-resistant bacterial strains. Lower-denomination and physically worn banknotes exhibited higher contamination burdens than higher-denomination or newer notes. Conclusion Bacterial contamination of circulating currency is highly prevalent across African settings and includes clinically important and antimicrobial-resistant bacterial species. These findings suggest that circulating currency may serve as an underrecognized environmental reservoir and a potential interface for microbial exchange between human, food, and environmental systems. From a One Health perspective, strengthening hand hygiene, discouraging simultaneous handling of food and money and improving currency management may help reduce contamination risks and limit microbial dissemination within communities.

Source: Frontiers in Public Health

DOI: 10.3389/fpubh.2026.1921421