Thousands of wastewater samples from sewage systems across the US get flown and trucked to a lab in Cambridge, Massachusetts, every week. Inside the facility, which is owned by the company Biobot Analytics, employees in white lab coats prepare to test the samples for traces of the virus that causes covid-19. Since 2020, the lab has helped track the ongoing pandemic. Now, Biobot and other labs hope to expand the use of wastewater to track a wider array of diseases including the seasonal surges of flu and respiratory syncytial virus, or RSV.
鈥淲hen you鈥檙e using the toilet, you鈥檙e essentially flushing down a medical sample that is then aggregated in the sewers,鈥� says , a data scientist at Biobot. 鈥淏y looking at the wastewater, we鈥檙e essentially looking at a community-level urine or stool sample.鈥�
Such efforts could also support a more permanent wastewater surveillance system for tracking both familiar and new diseases. On 19 January, the US National Academies of Sciences, Engineering, and Medicine describing how to 鈥渟olidify this emergency response to the covid-19 pandemic into a national system鈥� that can provide updates on 鈥渆ndemic and newly emergent microbial threats for public health action鈥�.
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The idea of monitoring wastewater to spot disease trends began with efforts to track the transmission of poliovirus in the 1930s. In the decades since, improved techniques for growing isolated cells in labs and analysing DNA have made the concept more practical.
Zeroing in on microbes鈥� genetic material can help reveal the presence of the pathogens in wastewater. Lab workers mix wastewater samples with tiny magnetic beads tailored with special proteins that latch onto the target molecules. This allows commercial purification machines to use a magnetic probe to hold onto the markers while shaking and rinsing trays of wastewater samples.
The purified sample undergoes a standard genetic analysis that measures the number of copies of the virus genome per millilitre of sewage. That changing concentration of viral fragments in wastewater can reveal trends in how covid-19 is circulating within towns and cities 鈥� Biobot says this approach can reliably detect the virus when there is at least one infected person in a community of 6500 people.
Biobot鈥檚 lab currently analyses several thousand wastewater samples each week from more than 400 locations in all 50 US states, along with territories such as Puerto Rico and Guam and some tribal communities. Efforts so far have focused on covid-19, but Biobot has also been helping to monitor community levels of the mpox virus that began spreading in regions beyond West and central Africa in 2022.
Other companies have also gotten in on the wastewater surveillance business. The US Centers for Disease Control and Prevention previously had a contract with the Canadian company LuminUltra before switching over to Biobot starting in 2022. The government agency is also working with companies such as Ginkgo Bioworks to perform focused on the toilets used during international flights.
Wastewater surveillance has become a routine part of the pandemic response in much of the world. The European Union implemented such聽聽at wastewater treatment plants starting in March 2021. And China appears to be expanding its聽聽beyond major cities such as Beijing and Shenzhen following the end of the government鈥檚聽zero-covid听辫辞濒颈肠测.
This sort of surveillance can鈥檛 pinpoint exact individuals who may have a given disease. But it can provide a big picture sense of what is happening at a time when fewer people are testing for covid-19 or getting their test results officially recorded, says , a physician and genetics researcher at Stanford University in California who co-authored the report by the National Academies.
Having the capability to monitor multiple public health threats could prove useful well beyond the covid-19 pandemic, given how the system has already helped to track the spread of mpox and the re-emergence of poliovirus. 鈥淗ad that system not existed, it wouldn鈥檛 be so easy to build those capabilities from the ground up,鈥� says Bhatt.
The US government has so far committed more than $683 million to keep the national wastewater surveillance system going through 2025. In February, Biobot renewed its US government contract to continue efforts through the summer. The company has also begun thinking about future targets.
鈥淭he next question at parties is, 鈥榗an we do this for flu, can we do this for RSV?鈥欌�� says Duvallet. 鈥淎nd yeah, you can 鈥� we鈥檙e working on it.鈥�
