Associations Between Ambient Temperature and Enteric Infections by Aetiology: A Systematic Review and Meta-Analysis

Background: Studies have quantified the associations between ambient temperature and all-cause enteric infections. Temperature sensitivity in enteric infections, however, may be pathogen dependent. Here, we sought to identify aetiology-specific associations between ambient temperature and enteric infections.    Methods: We conducted a systematic review and meta-analysis study by searching PubMed, Web of Science, and Scopus for research articles published from 2000 to 2019. We only included studies that quantified the effects of ambient temperature increases on enteric infections. Two authors screened the studies, one extracted the data from the eligible studies, and four performed data verification. The overall risks were obtained by pooling the relative risk of enteric infection by aetiology for each 1°C temperature rise using random-effects modelling and robust variance estimation for the correlated effect estimates.  Findings: The 2170 screened studies generated 80 eligible for systematic review and 56 eligible for meta-analysis. The overall increased risks per 1°C temperature rise were 1·05 (95%CI 1·04–1·07; I2 :97%) for salmonellosis, 1·07 (1·04–1·10; I2 :99%) for shigellosis, 1·02 (1·01–1·04; I2 :98%) for campylobacteriosis, 1·05 (1·04–1·07; I2 :36%) for cholera, 1·04 (1·01–1·07; I2 :98%) for Escherichia coli enteritis, and 1·15 (1·07–1·24; I2 :0%) for typhoid. Reduced risks per 1°C temperature rise were found for rotaviral enteritis at 0·96 (0·90–1·02; I2 :97%), and noroviral enteritis at 0·89 (0·81–0·99; I2 :96%). Interpretation: Enteric infections have varying associations with ambient temperature depending on their aetiology. Future projections for temperature-related enteric infections should account for differing temperature sensitivity in enteric pathogens. Funding: Japan Society for the Promotion of Science (Kakenhi) Grant-in-Aid for Scientific Research. Declaration of Interest: We declare no competing interests