LAST week, health officials announced the detection of polio in New York City鈥檚 sewage system, suggesting transmission of a virus that had all but disappeared globally. Earlier this year, a polio outbreak among children in London was similarly detected before any clinical cases were picked up. While such findings are worrisome, they also highlight the benefits of waste water surveillance for detecting and tackling outbreaks fast.
Using sewer sludge as a public health litmus test isn鈥檛 a new idea. Since the mid 2000s, researchers have known that waste water can offer important insights into drug use, disease transmission and even diet. But it wasn鈥檛 until the covid-19 pandemic that governments began to seriously tap into sewage鈥檚 potential.
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Trace amounts of genetic material from viruses, including covid-19, can be detected in waste well before people are symptomatic. This allows for earlier and cheaper detection. For these reasons, governments across the globe established waste water surveillance programmes to monitor covid-19 outbreaks, as we report in our feature.
Now, those same systems are being used to track, and potentially contain, the spread of other diseases. Earlier this month, Canadian officials announced plans to test sewage for monkeypox. Similar proposals have been floated in cities throughout the US.
But the wealth of information that can be gleaned from sewer slurry raises ethical questions too. Waste water surveillance takes disease monitoring out of the hands of individuals. Samples can鈥檛 be traced to a single person, but, depending on where they are collected, can reveal the health of those living in a neighbourhood or even a particular building. Citizens are wary of the method being used to track lifestyle factors, genetic information or even mental health.
It is clear that these privacy concerns must be addressed with proper regulation. Only in doing so can we can tap into the revolutionary potential of waste water at a time when we need every disease surveillance tool in our arsenal.
