Abstract
BACKGROUND: Diarrhoea among children under five years old (i.e. childhood diarrhoea) causes significant morbidity and mortality in low and middle-income countries (LMICs). We conducted this systematic review and meta-analysis to quantify the proportion of childhood diarrhoea attributable to Campylobacter spp., diarrhoeagenic Escherichia coli (E. coli), Salmonella spp., and Shigella spp. in LMIC settings. METHODS: We included epidemiological studies published between 2000 and 2025, and extracted data on study location, sample size, and pathogen-specific parameters. Two reviewers independently performed database searches, publication screening, data extraction, and quality assessment, with any conflicts resolved by a third reviewer. We reported the results of the meta-analysis as pooled proportions (positive samples divided by the total samples tested for each enteropathogen) and 95% confidence intervals. We assessed all potential sources of heterogeneity using univariable and multivariable meta-regression, quantified moderator contributions as pseudo-R(2) values based on reductions in τ(2), and tested for interaction effects. We also evaluated robustness through leave-one-out analyses, sequentially excluding individual studies to examine their influence on pooled estimates and heterogeneity. RESULTS: We included 71 records encompassing 84 studies. Pooled proportions were 8.6% for Campylobacter spp., 23.0% for diarrhoeagenic E. coli (DEC), 2.6% for Salmonella spp., and 8.8% for Shigella spp., with wide variation across studies. Subgroup analyses showed higher proportions of Campylobacter spp. and Shigella spp. in Asia and with polymerase chain reaction-based detection, and greater DEC proportions in America and Africa. Salmonella spp. remained low across regions and study designs. Year- and country-specific analyses showed no consistent temporal trends, though DEC peaked in 2014 (77.9%, two studies) and Shigella spp. was higher in 2020 (20.7%, ten studies), both driven by a limited number of studies. CONCLUSIONS: Standardising diagnostic methods and study designs is essential for reducing heterogeneity and improving the reliability of pooled proportion estimates in epidemiological research on enteric pathogens. Improving water supply, sanitation, hygiene, and food safety remains crucial for reducing the burden of childhood diarrhoea in LMICs.