Background Understanding pathogen-specific relationships with climate is crucial to informing interventions under climate change. Methods We matched spatiotemporal temperature, precipitation, surface water, and humidity data to data from a trial in rural Bangladesh that measured diarrhea and enteropathogen prevalence in children 0-2 years from 2012-2016. We fit generalized additive models and estimated percent changes in prevalence using projected precipitation under Shared Socio-Economic pathways describing sustainable development (SSP1), middle of the road (SSP2), and fossil fuel development (SSP5) scenarios. Findings An increase from 15 degrees C to 30 degrees C in weekly average temperature was associated with 5.0% higher diarrhea, 6.4% higher Norovirus, and 13.0% higher STEC prevalence. Above-median precipitation was associated with 1.27-fold (95% CI 0.99, 1.61) higher diarrhea; higher Cryptosporidium, tEPEC, ST-ETEC, STEC, Shigella, EAEC, Campylobacter, Aeromonas, and Adenovirus 40/41; and lower aEPEC, Giardia, Sapovirus, and Norovirus prevalence. Other associations were weak or null. Compared to the study period, diarrhea prevalence was similar under SSP1 (7%), 3.4% (2.7%, 4.3%) higher under SSP2, and 5.7% (4.4%, 7.0%) higher under SSP5. Prevalence of pathogens responsible for a large share of moderate-to-severe diarrhea in this setting (Shigella, Aeromonas) were 13-20% higher under SSP2 and SSP5. Interpretation Higher temperatures and precipitation were associated with higher prevalence of diarrhea and multiple enteropathogens; higher precipitation was associated with lower prevalence of some enteric viruses. Under likely climate change scenarios, we projected increased prevalence of diarrhea and enteropathogens responsible for clinical illness. Our findings inform pathogen-specific adaptation and mitigation strategies and priorities for vaccine development.

Background: Climate change may influence the effectiveness of environmental interventions. We investigated if climate and environment modified the effect of low-cost, point-of-use water, sanitation, and handwashing (WASH) interventions on diarrhea and predicted intervention effectiveness under climate change scenarios. Methods: We analyzed data from a cluster-randomized trial in rural Bangladesh that measured diarrhea prevalence in children 0-2 years from 2012-2016. We matched remote sensing data on temperature, precipitation, humidity, and surface water to households by location and measurement date. We estimated prevalence ratios (PR) for WASH interventions vs. control stratified by environmental factors using generative additive models and targeted maximum likelihood estimation. We estimated intervention effects under predicted precipitation in the study region in 2050 for climate change scenarios from different Shared Socioeconomic Pathways (SSPs). Findings: WASH interventions more effectively prevented diarrhea under higher levels of total precipitation in the previous week and when there was heavy rain in the previous week (heavy rainfall PR = 0.38, 95% CI 0.23-0.62 vs. no heavy rainfall PR = 0.77, 0.60-0.98). We did not detect substantial effect modification by other environmental variables. WASH intervention effectiveness increased under most climate change scenarios; in a fossil-fueled development scenario (SSP5), the PR was 0.46 (0.44-0.48) compared to 0.67 (0.65-0.68) in the study. Interpretation: WASH interventions had the strongest effect on diarrhea under higher precipitation, and effectiveness may increase under climate change without sustainable development. WASH interventions may improve population resilience to climate-related health risks. Funding: Bill & Melinda Gates Foundation, National Institute of Allergy and Infectious Diseases, National Heart, Lung, And Blood Institute