Understanding pathogen-specific relationships with climate is crucial to informing interventions under climate change.

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.

An increase from 15°C to 30°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.

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.

Bill & Melinda Gates Foundation, National Institute of Allergy and Infectious Diseases, National Heart, Lung, And Blood Institute, Stanford University School of Medicine, Chan Zuckerberg Biohub

We searched Google Scholar and Scopus for studies published from January 1, 2000 to present using the following three queries: 1) child; and diarrhea OR “enteric infection”; and meteorological OR environmental OR “surface water” OR “standing water”; and risk AND/OR factors; 2) Climate AND change AND project* AND diarrhea OR diarrhoea; 3) climate AND change AND project* OR model AND enter* AND infect* AND E. coli. Studies generally focused on individual risk factors for diarrhea transmission or enteric infection, with an emphasis on temperature and precipitation. Studies found that higher temperatures were associated with higher incidence of bacterial diarrhea and lower incidence of viral diarrhea; few studies have investigated associations between temperature and parasitic diarrhea. Heavy rainfall, particularly after dry periods, was associated with higher diarrhea prevalence, though heavy rainfall during rainy seasons was found to protect against diarrhea incidence. Similarly, flooding of surface water and shallow wells was also associated with higher diarrhea prevalence. Very few studies investigated associations between diarrhea or enteropathogen carriage and surface water presence, or humidity. A recent individual participant meta-analysis of studies in 19 low- and middle-income countries found that higher precipitation was associated with a small decrease in enterotoxigenic E. coli (ETEC) and Campylobacter spp. prevalence and no difference in Shigella, Cryptosporidium, or …