Nature Reviews Microbiology details how climate change is spreading waterborne diseases

Climate change is reshaping the global geography of waterborne disease transmission, according to a comprehensive review in Nature Reviews Microbiology published today (https://www.nature.com/articles/s41579-026-01338-3). Waterborne pathogens have long been linked to rainfall-driven runoff and flooding, but the emerging picture is more complex: shifting climates can alter exposure routes, pathogen persistence, and host infection opportunities simultaneously.

The review highlights that waterborne diseases continue to drive enormous mortality, with infectious diarrhea causing nearly 1.2 million deaths each year. While public health gains from decades of improved sanitation have helped, the authors warn that more frequent extreme weather events could erode this progress by stressing water systems and increasing contamination risk.

A key finding is that climate change does not affect all pathogens in uniform ways. Bacteria, viruses, and parasites respond differently to environmental drivers such as temperature, moisture, sunlight exposure, and water availability. This pathogen-specific variability matters for prediction models and for how health agencies prioritize interventions during outbreaks.

Transmission is influenced through multiple pathways. Climate shifts can change whether pathogens survive long enough in aquatic environments, how widely they disperse through infrastructure and food-water contact, and how readily they infect new hosts. Consequently, the same climate event may raise risk for one pathogen while suppressing another.

Flooding remains an obvious hazard because it can breach drinking water infrastructure and transport contaminants into distribution networks. Yet the review emphasizes that drought can also increase risk indirectly by reducing access to safe water, concentrating use into fewer sources, and modifying sanitation practices. Such changes can increase opportunities for fecal contamination and person-to-person spillover.

Temperature generally favors bacterial growth, which can intensify bacterial waterborne outbreaks under warmer conditions. In contrast, some viruses—including norovirus, rotavirus, and adenovirus—may spread more efficiently under cooler, drier conditions. The review notes that this means a warmer world could, for certain viral pathogens, reduce transmission potential rather than increase it.

Because of these differences, the review argues that public health planning should avoid one-size-fits-all strategies. Surveillance, risk communication, and interventions should be tailored to the likely pathogen mix under local climate regimes.

To reduce risk, the authors recommend “no-regrets” investments that strengthen preparedness across scenarios. These include climate-resilient water, sanitation, and hygiene (WASH) infrastructure; expanded pathogen-specific surveillance to enable early identification of circulating organisms; and vaccination program strengthening where vaccines exist, such as for cholera, rotavirus, polio, hepatitis A, and typhoid.

The paper concludes that no single adaptation strategy will protect against every waterborne disease. Instead, climate resilience efforts must incorporate pathogen-specific responses to environmental change, enabling agencies to better anticipate future outbreak patterns.