Is the next pandemic brewing in wastewater? A microbiologist warns

Few people think about the water flushed daily down sinks, bathtubs, and toilets. We prefer to leave the issue of sewage to treatment plants. Yet life thrives in the sewer system, which one day could threaten us all. According to Sunil Pandey, a microbiologist at George Mason University, the next pandemic could develop in wastewater, so action is needed before it is too late.

Secondary soup, or what ends up in wastewater

Human excreta are more than just leftover food and urine produced by blood filtration. Rich in organic matter, they provide an excellent nutrient source for microorganisms, both beneficial and harmless, as well as pathogenic. Every day, vast amounts of bacteria, viruses, and fungi enter wastewater to multiply and evolve – a prime arena for microbial competition.

In an article published on November 15 on the scientific platform Springer Nature Research Community, Sunil Pandey draws attention to another component of sewer soup – antibiotics and other medications consumed in large quantities worldwide.

With every flush, pharmaceuticals enter the sewage system, providing a growth stimulus for the bacteria present. Pathogens mutate and begin sharing resistance genes against specific substances. Quietly, microbes capable of sparking a new pandemic are being born in the pipes beneath our feet. Studies published in Nature and The Lancet Microbe revealed that wastewater in New York, New Delhi, and Nairobi already contains extremely high concentrations of resistance genes against known drugs.

Will the next pandemic emerge from poverty?

Why would pathogens from wastewater attack humans? Isn’t that what sewage systems and treatment plants are for – to keep us safe? Unfortunately, wastewater regularly leaks, is illegally discharged into rivers or soil, or never reaches treatment at all. In Poland, as late as 2021, the Central Statistical Office reported 6 percent of untreated sewage, while in the UK in 2024, water companies released sewage directly into rivers and seas for 3.6 million hours.

In poor regions of Asia and sub-Saharan Africa, wastewater treatment levels in some countries do not exceed 10 percent. Most water contaminated with feces, microorganisms, and pharmaceuticals enters the natural environment and often also drinking water sources. This is where the risk of mutated pathogens transferring to humans is highest. Five years ago, we could see how easily a pandemic spreads between continents, regardless of wealth.

Diagnosis in the sewer

Before the first Covid-19 case was confirmed in Nepal in 2020, the virus was detected in wastewater in Kathmandu. The same scenario played out in Tokyo, Amsterdam, and Boston, proving a universal truth – the greatest health threats are not found in hospitals but in sewage systems. By the time people begin to fall ill and die, effective prevention is usually too late.

In his essay, Sunil Pandey argues that a change in attitude toward wastewater is necessary – instead of seeing it as waste, we should view it as a source of valuable knowledge. A global monitoring system for water flowing from our toilets is the first step in stopping the development of the next pandemic. The second is investing in sewage systems and treatment plants worldwide. We cannot assume that deficiencies in this area are solely the internal problem of Bangladesh or Angola. Global disease transfer is easier than ever, so sanitation infrastructure matters everywhere.