It is possible that the next epidemic could be spotted early in wastewater. Wastewater surveillance has been used to monitor outbreaks of diseases such as polio, norovirus, and hepatitis A in the past. The advantage of wastewater surveillance is that it can provide a community-wide view of the prevalence of a virus or other pathogen, even before people start showing symptoms.
According to wastewater researchers, routine monitoring at sewage treatment plants could provide a powerful early warning system for the next flu or norovirus epidemic, alerting hospitals to prepare and providing vital health information to public health agencies.
Scientists from the University of Bath, Bangor University, and the UK Health Security Agency conducted the first large-scale and comprehensive wastewater-based epidemiology (WBE) study in the UK, analyzing wastewater from ten cities for both chemical and biological markers of health, such as pesticides, pharmaceuticals, and disease-causing viruses.
On nine days in November 2021, they collected samples from each location at hourly intervals for 24 hours. Each day’s samples were collected and analyzed for trace chemical markers using mass spectrometry techniques. The samples were also tested for viral genetic material (SARS-CoV-2, norovirus, and adenovirus). The total population of the sampling catchment area was approximately 7 million people.
Our research has shown that only 10 daily samples from 10 wastewater treatment plants are required to provide anonymous and unbiased information on the health of 7 million people – this is significantly less expensive and faster than any clinical screening process.Professor Barbara Kasprzyk-Hordern
Detecting trace chemicals
The researchers were able to tell whether pharmaceuticals had passed through the human body or had been disposed of directly into the wastewater system by using highly sensitive chemical analysis that could distinguish between very similar markers. They could also tell if chemicals like pesticides had been ingested or washed into the wastewater system from agricultural land.
The team discovered that differences in chemical marker levels were mostly determined by the size of the population in the catchment area, but there were some outliers. When compared to other cities, one city had a much higher concentration of ibuprofen in the water, implying direct disposal from industrial waste.
Identifying disease outbreaks
The researchers discovered localized outbreaks of norovirus, Covid-19, and flu, but they could also link them to increases in the use of over-the-counter pain relievers like paracetamol. The findings suggest that large-scale wastewater analysis, dubbed wastewater-based epidemiology, could detect new outbreaks of diseases in communities early on, before large numbers of people were admitted to hospitals.
The chemistry work on the project was led by Professor Barbara Kasprzyk-Hordern of the University of Bath’s Water Innovation Research Centre and Institute for Sustainability. “Most people reach for paracetamol when they first get sick and try to treat their illnesses at home,” she explained.
“Looking for large spikes in paracetamol use could provide an early warning sign of an infectious disease outbreak in the community.” We can also detect inflammation markers and thus look for any potential links between poor health and exposure to harmful chemicals, such as pesticides from food or industrial sources of chemicals.”
“Our research has shown that only 10 daily samples from 10 wastewater treatment plants are required to provide anonymous and unbiased information on the health of 7 million people – this is significantly less expensive and faster than any clinical screening process.” As a result, this has the potential to be a very powerful tool for providing a holistic understanding of public health in various communities.”
“Norovirus and seasonal flu have always been a huge problem in hospitals each winter; now Covid-19 has added to this problem,” said Professor Davey Jones, who led a team at Bangor University that analyzed the wastewater for viruses. Our proof-of-concept study demonstrated the potential for Wastewater Based Epidemiology to provide an early warning surveillance system for these and other diseases, allowing hospitals to prepare for local outbreaks.”