As climate change reshapes our environment, the connection between shifting climates and infectious diseases becomes increasingly evident. Waterborne diarrheal diseases, once primarily a concern in low- and middle-income countries (LMICs), are now emerging as a growing threat even in higher-income regions. Changes in precipitation patterns, along with rising incidents of flooding and drought, amplify the conditions that allow these diseases to thrive.
These illnesses disproportionately affect vulnerable populations, particularly children. Beyond the immediate health risks, their long-term effects are severe. Repeated infections can lead to chronic malnutrition, impaired cognitive development, and reduced economic productivity later in life, creating a cycle of disadvantages extending far beyond the initial disease burden.
In response to this evolving threat, the EU-funded SPRINGS project is leading the efforts to understand and address the impact of climate change on waterborne diarrheal diseases. By studying the link between climate and 4 diarrhoeal pathogens, SPRINGS aims to inform and prioritise political responses, emphasising the urgent need to address the broader links between climate change and public health.
We spoke with Dr Vanessa Harris from the Amsterdam University Medical Centre and SPRINGS project Coordinator, and Dr Josh Colston, a leading researcher in the project from the University of Virginia, to get more insights into the pathogens that are under study in SPRINGS.
One of the important decisions to be made at the start of the project was selecting which pathogens to study. Dr Josh Colston highlighted that one of the aims was to cover a broad taxonomic spectrum. "We wanted representation across different types of pathogens. That's why we selected a virus, a bacterium, and two protozoa." The chosen pathogens: Rotavirus, Campylobacter, Cryptosporidium, and Giardia, offer insights into the various ways diarrhoeal diseases are transmitted, how they impact the human body, how they respond to environmental changes, and what interventions could be relevant to prevent the impact of different waterborne diarrhoeal diseases.
Rotavirus, a viral agent, is the leading cause of death from diarrhoea in the world, especially among young children. It is known for its ability to spread through contaminated water and, as research shows, through other routes such as respiratory droplets. As the climate warms, scientists are interested in understanding how seasonal patterns of rotavirus transmission might change, especially in regions where cold seasons are becoming milder.
Campylobacter, the bacterial pathogen of choice, is responsible for the most diarrheal infections in Europe. Dr Vanessa Harris noted that Campylobacter thrives in warmer climates. As global temperatures rise, the risk of Campylobacter outbreaks, particularly through animal farming and contaminated water, is expected to increase.
The inclusion of two protozoa, Cryptosporidium and Giardia, reflects their growing importance in both low- and high-income countries. These parasites are particularly resistant to standard water treatment methods like chlorination, making them significant concerns for under-treated water. The choice to include Giardia, in particular, came from its relevance in European contexts, where the disease burden is high.
Climate extremes, such as increased rainfall and droughts, frequently lead to contamination of water sources, especially in rural areas where sanitation is poor, or close contact with animals is common. In these settings, heavy rains can wash faecal matter into drinking water, food crops, and other surfaces, increasing the risk of disease outbreaks among vulnerable populations.
Dr Colston provided a vivid example of this, "Imagine heavy rainfall in a village where chickens roam freely. Their faeces get washed into the water system, which is then used for drinking or farming. These types of events are becoming more common with climate change." This scenario, while often associated with LMICs, has relevance for high-income settings, too, where industrial farming and intensive animal husbandry create similar risks of contamination.
Beyond immediate illness, the long-term effects of diarrhoeal pathogens are often underestimated. In children, repeated exposure to diarrhoeal pathogens can affect the body’s ability to absorb essential nutrients. This condition can lead to chronic malnutrition and stunted growth. As Dr Colston explains, "Even when children receive adequate nutrition, repeated infections damage their intestines, reducing their ability to absorb nutrients." Over time, this affects their cognitive abilities, physical development, and growth, contributing to a range of metabolic conditions such as diabetes, cardiovascular diseases, and even economic productivity in adulthood.
The silent burden of chronic infections is also frequently underreported. For example, Giardia infections may not always cause noticeable symptoms but can still lead to long-term infections and further exacerbate health and developmental challenges.
Climate change amplifies existing health inequalities in significant ways. While European nations and other high-income countries are not immune to the rise of waterborne diarrheal diseases, the burden of these pathogens is closely tied to access to sanitation. The uneven distribution of resources between the global North and South exacerbates both the risks and the long-term impacts of these diseases.
As the SPRINGS project moves forward, its findings will be essential not only for understanding the immediate effects of climate change on waterborne diarrheal diseases but also for informing policies that address the broader health implications of climate change and strengthen resilience to these unequal risks.
About the project:
SPRINGS is an EU-funded project focused on addressing the impact of climate change on waterborne diarrheal diseases. Diarrheal diseases are currently the third leading cause of death in children under 5 years of age globally. Compounded by global climate projections indicating increased precipitation, flooding, and drought, there is a looming threat to the progress made in reducing diarrheal disease burden. To inform and prioritise effective political responses, SPRINGS is building 4 case studies in Italy, Ghana, Romania, and Tanzania with contrasting vulnerabilities.