Baltimore, Maryland—Researchers at the University of Maryland School of Medicine have identified social, economic, and environmental factors that may determine how climate change reshapes the burden of childhood diarrheal disease in sub-Saharan Africa. The findings, published August 6 in Nature Communications, indicate that rising temperatures and shifting rainfall patterns will not affect every pathogen or community in the same way. Instead, future disease risk will emerge from the interaction of climate conditions with household resources, public infrastructure, vaccination, and the ability of families to reach medical care. The work offers a detailed, pathogen-specific view of how climate change could influence one of the most persistent threats to children under five.
The analysis drew on more than 9,300 cases of moderate-to-severe diarrhea collected in Mali, Kenya, and The Gambia through the Global Enteric Multicenter Study, or GEMS, and its follow-up project, Vaccine Impact on Diarrhea in Africa, known as VIDA. Both studies generated extensive clinical, laboratory, demographic, and household data from children living in communities with differing levels of infrastructure and economic resilience. The researchers examined four major causes of severe childhood diarrhea: Cryptosporidium, Shigella, rotavirus, and enterotoxigenic Escherichia coli, or ETEC. Their objective was not simply to determine whether climate change increases disease, but to identify which climate variables matter for each pathogen and which populations are most likely to experience the greatest effects.
Diarrheal disease remains a major cause of childhood illness and death worldwide. The World Health Organization identifies it as the third leading cause of death among children younger than five and a leading contributor to malnutrition. Repeated infections can damage the intestinal lining, impair nutrient absorption, and create a cycle in which illness and undernutrition reinforce one another. Climate change may intensify these processes because many enteric pathogens are sensitive to temperature, humidity, water availability, and flooding. Warmer conditions can accelerate microbial replication or extend the period during which pathogens survive in the environment, while heavy rainfall can overwhelm sanitation systems and contaminate drinking-water sources. Drought can also force communities to rely on unsafe water or travel farther to obtain it.
The new study shows that these mechanisms operate differently depending on the organism and location. In Kenya, temperature was strongly associated with the risk of Shigella, Cryptosporidium, and ETEC. In Mali and The Gambia, rainfall-related measures were more influential for rotavirus, Cryptosporidium, and ETEC. These differences reflect the distinct biology and transmission pathways of the pathogens. Shigella spreads primarily through fecal-oral transmission and can move rapidly through contaminated food, water, and close household contact. ETEC produces toxins that disrupt intestinal fluid balance, while Cryptosporidium forms environmentally hardy oocysts that can persist in water. Rotavirus, an exceptionally contagious virus, can spread efficiently wherever sanitation is limited and susceptible children come into contact with contaminated surfaces or bodily fluids.
The researchers also investigated whether so-called adaptive capacity factors could modify climate-associated risks. Adaptive capacity describes the practical resources that allow households and communities to anticipate, withstand, and recover from environmental stress. In the analysis, children from households with access to transportation, electricity, or a television generally showed lower climate-associated risks for certain pathogens than children from households without those resources. These factors are not necessarily direct biological defenses against infection. Rather, they may act as indicators of mobility, economic stability, access to information, the ability to seek treatment, and the capacity to obtain safer water or food when environmental conditions deteriorate.
Access to improved drinking water emerged as particularly important for Cryptosporidium. Modeling indicated that a decline in access to improved water could substantially increase Cryptosporidium incidence under future climate scenarios across all three study sites. Conversely, expanding access to improved drinking water was projected to reduce incidence. The finding is consistent with the parasite’s transmission biology: Cryptosporidium oocysts can survive in water and are resistant to commonly used levels of chlorine, making filtration, source protection, sanitation, and reliable water infrastructure important components of prevention. For families living in areas where water sources are vulnerable to flooding, contamination, or seasonal shortages, even modest disruptions can increase exposure.
The climate projections examined in the study suggest that temperatures could rise substantially by 2055, but the resulting effect on precipitation and Cryptosporidium incidence was modest across the three study locations. This does not mean that climate change will have little effect on diarrheal disease. Rather, it demonstrates why broad assumptions about climate and infection can be misleading. A warmer future may alter risks through several pathways at once, while local precipitation patterns, sanitation conditions, pathogen ecology, and household behavior determine how those changes are expressed. A climate variable that predicts increased risk for one pathogen in one country may have a weaker association—or a different association altogether—in another setting.
The findings also reinforce the importance of vaccination as part of climate adaptation. Rotavirus vaccination can prevent severe disease caused by one of the most transmissible viral agents of childhood diarrhea, reducing the number of children who require hospitalization and protecting health systems during periods of heightened environmental pressure. Vaccination cannot eliminate every cause of diarrhea, and it does not replace clean water, sanitation, or clinical care. However, by lowering vulnerability to a major pathogen, immunization can reduce the consequences of climate-related disruptions. The researchers argue that vaccine delivery should be considered alongside infrastructure improvements, economic development, transportation access, and public-health surveillance when governments plan for a changing climate.
“This research highlights the importance of looking beyond environmental exposures alone,” said Stefan Kappe, director of the University of Maryland School of Medicine’s Center for Vaccine Development and Global Health. “Building resilience to climate change will require a combination of public health interventions, infrastructure improvements, economic development, and expanded access to lifesaving vaccines.” Megan Kowalcyk, the study’s lead author and a research associate at the center, said the results show that disease risk depends not only on temperature and rainfall but also on the factors that shape a family’s ability to adapt and respond to environmental stressors.
The study’s site-specific and pathogen-specific approach gives public-health planners a more precise way to anticipate future disease patterns. Instead of treating climate change as a single exposure with a uniform outcome, the analysis connects environmental conditions with biological mechanisms and household resilience. That perspective could help identify where water improvements, vaccine campaigns, transportation networks, or disease surveillance would have the greatest protective effect. The GEMS and VIDA programs were funded by the Gates Foundation and led by Myron M. Levine and Karen L. Kotloff. Together, their data suggest that protecting children from climate-driven diarrheal disease will depend not only on reducing greenhouse-gas emissions, but also on strengthening the social and public-health systems that enable vulnerable communities to withstand environmental change.
Subject of Research: People
Article Title: Vulnerability to climate-driven pathogen-specific diarrheal diseases: secondary analysis from the Global Enteric Multicenter Study and Vaccine Impact on Diarrhea in Africa follow-up
News Publication Date: August 19, 2026
Web References: University of Maryland School of Medicine Center for Vaccine Development and Global Health: https://www.medschool.umaryland.edu/cvd/ ; Global Enteric Multicenter Study: https://www.medschool.umaryland.edu/gems/ ; Vaccine Impact on Diarrhea in Africa: https://www.medschool.umaryland.edu/cvd/vaccines/studies–projects/vaccine-impact-on-diarrhea-in-africa-vida/ ; World Health Organization diarrheal disease fact sheet: https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease
References: Nature Communications, DOI: 10.1038/s41467-026-76189-w. Initial analysis: Journal of Infectious Diseases, DOI: 10.1093/infdis/jiag306.
Keywords: climate change, childhood diarrhea, viral diseases, rotavirus, Cryptosporidium, Shigella, ETEC, sub-Saharan Africa, infectious disease, vaccination, drinking water, public health, epidemiology, climate resilience
