John Snow, a physician in London, found himself in the middle of a devastating cholera outbreak in 1854. In a painstaking investigation in the densely populated Soho district, he traced the source of the epidemic to a contaminated water pump on Broad Street, before knowledge of the causative organism. The epidemic subsided when the pump handle was subsequently removed. Snow’s work underscores the potential of disease prevention and control. It also leads us to a tantalising question: What could he have achieved with the tools of today? Could he have sounded the alarm at the earliest stages that an outbreak was imminent?
A public health tool revisited
This hypothetical scenario is now a tangible reality. A recently published study in The Lancet Global Health reiterated the promise of using wastewater for public health surveillance. This strategy, originally proposed more than 80 years ago to monitor the spread of poliovirus within communities, played a role in confirming India’s victory over poliovirus. It gained fresh relevance during the COVID-19 pandemic, when it was identified as an approach for tracking the spread of SARS-CoV-2.
