Rising temperatures and extreme weather events may be increasing the risk of virus exposure from sewage-contaminated waters, a new study warns. Scientists have found that viruses from raw sewage can persist in rivers, lakes, and seas for days, raising public health concerns.
Heavy rainstorms often overload sewer systems, leading to untreated sewage being discharged into natural water bodies. This waste carries viruses such as enterovirus and norovirus, which can remain infectious for days, even after passing through wastewater treatment plants. In seawater, enteric viruses stayed infectious for up to three days at 30°C, while cooler temperatures extended their lifespan to a week. Sunlight reduced their viability to less than 24 hours on sunny days, but they survived for 2.5 days in cloudy conditions.
To minimize infection risks, researchers advise avoiding recreational activities in contaminated waters for at least 2.5 days after cloudy weather and 24 hours after sunny conditions. The study highlights the urgent need for improved sewage treatment worldwide, as climate change could worsen sewage-related contamination. Governments must strengthen public health strategies to combat the growing risks of sewage-borne infections.