Climate change is altering the spread of waterborne diseases around the world, according to a comprehensive review published today in Nature Reviews Microbiology. The publication is the most up-to-date and comprehensive analysis to date examining how climate change influences waterborne diseases.
The review warns that more frequent extreme weather events could undermine decades of progress in reducing waterborne diseases, which contribute to nearly 1.2 million deaths from infectious diarrhea each year.
Led by researchers from the Colorado School of Public Health at the University of Colorado Anschutz and the University of Washington School of Public Health, the review found that climate change does not affect all disease-causing microorganisms, known as pathogens, in the same way.
Instead, bacteria, viruses and parasites each respond differently to changing environmental conditions, showing why managing the public health response should be tailored to specific pathogens.
“We want people to know climate change changes the conditions that allow pathogens to spread,” said the review’s co-author Elizabeth Carlton, PhD, professor and chair of the Department of Environmental and Occupational Health at the Colorado School of Public Health. “It’s making it harder to control some of the world’s most deadly infectious diseases by creating more favorable conditions for transmission.”
Climate change affects transmission in multiple ways
The review explains that climate change alters the environmental conditions that determine whether pathogens survive, spread and infect new hosts. For example, while waterborne diseases are often associated with flooding and heavy rainfall that carry pathogens into drinking water supplies, the authors explain droughts can also increase disease risk by reducing access to safe water and changing how people use the water that is available.
The review also explains that rising temperatures generally promote bacterial growth, while some viruses, including norovirus, rotavirus and adenovirus, spread more easily under cooler, drier conditions – and may, in fact, decrease in a warmer world.
Public health strategies that can reduce risk
The review outlines practical steps that can help communities adapt to the growing threat of climate-driven waterborne diseases.
- Invest in climate-resilient water, sanitation and hygiene (WASH) infrastructure. Safe drinking water, sanitation systems and hygiene practices remain among the most effective ways to prevent waterborne disease. Because floods, hurricanes and other extreme weather events can damage water and sanitation infrastructure, the authors emphasize the need for systems that can withstand climate-related stressors.
- Expand pathogen-specific disease surveillance. Early detection of outbreaks can help public health officials identify which pathogens are circulating and target interventions where they are needed most. Because bacteria, viruses and parasites respond differently to climate conditions, surveillance and response strategies should be tailored to specific pathogens rather than relying on a one-size-fits-all approach.
- Strengthen vaccination programs. Vaccines are already available for several major waterborne diseases, including cholera, rotavirus, polio, hepatitis A and typhoid. Increasing vaccine coverage can reduce disease burden, but climate-related disasters can disrupt distribution by damaging infrastructure, limiting access to affected communities and interrupting vaccine cold chains.
Employing tactics now can build resilence for the future
These strategies are described in the paper as “no-regrets” investments because they not only reduce waterborne disease today but also help communities become more resilient to the health impacts of climate change.
“Climate change is changing the rules of how these diseases spread,” Carlton said. “The good news is we already have many of the tools needed to reduce risk. The challenge now is making sure they're designed and deployed for the climate conditions we're facing today and the ones we'll face in the future.”
The authors conclude that no single strategy will protect against every waterborne disease. Instead, they say climate adaptation efforts should account for how individual pathogens respond to changing environmental conditions, allowing public health officials to better anticipate and prevent future outbreaks.
Key points
- Climate change has altered the way waterborne diseases are spreading.
- Changing environmental conditions affect bacteria, viruses and parasites differently.
- Floods and droughts can both increase disease risk.
- Public health officials should tailor strategies in response to individual diseases.
