Hands Are Frequently Contaminated with Fecal Bacteria and Enteric Pathogens Globally: A Systematic Review and Meta-analysis

Enteric pathogen infections are a leading cause of morbidity and mortality globally, with the highest disease burden in low-income countries. Hands act as intermediaries in enteric pathogen transmission, transferring enteric pathogens between people and the environment through contact with fomites, food, water, and soil. In this study, we conducted a systematic review of prevalence and concentrations of fecal indicator microorganisms (i.e., E. coli, fecal coliform) and enteric pathogens on hands. We identified 84 studies, reporting 35,440 observations of hand contamination of people in community or household settings. The studies investigated 44 unique microorganisms, of which the most commonly reported indicators were E. coli and fecal coliforms. Hand contamination with 12 unique enteric pathogens was reported, with adenovirus and norovirus as the most frequent. Mean E. coli prevalence on hands was 62% [95% CI 40%-82%] and mean fecal coliform prevalence was 66% [95% CI 22%-100%]. Hands were more likely to be contaminated with E. coli in low/lower-middle-income countries (prevalence: 69% [95% CI 48%-88%]) than in upper-middle/high-income countries (6% [95% CI 2%-12%]). The Review also highlights the importance of standardizing hand sampling methods, as hand rinsing was associated with greater fecal contamination compared to other sampling methods.