Optimising Resources and Results: Economic perspectives on wastewater surveillance
Wastewater and Environmental Surveillance, when used effectively as a tool complementary to clinical surveillance methods, can, thus, unleash huge public health benefits for the country
Long before the patients show up in hospitals, the germs silently accumulate in the wastewater beneath our cities.
Image: Ashish Vaishnav/SOPA Images/LightRocket via Getty Images
What if the sewage system running through your city's underbelly held secrets that could predict the next disease outbreak, even before a case has been reported? Sounds like science fiction, right? But it isn't. This is exactly what wastewater surveillance does.
What is Wastewater Surveillance, and how does it work?
After the devastation wreaked by the first two Coronavirus waves, India was more vigilant of the looming threat of another one. A nationwide vaccination drive, readying the infrastructure and personnel, promoting the prophylactic use of masks and social distancing, along with improved testing and surveillance, was a testament to this preparedness. Bengaluru and Ahmedabad reported SARS-CoV-2 spikes during the third wave of the pandemic well before the rise in clinical cases, sounding a metaphorical bugle. What made that prediction possible?
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Long before the patients show up in hospitals, the germs silently accumulate in the wastewater beneath our cities–vital signs of a festering infection, like the pulse of the population. And scientists read this pulse through Wastewater and Environmental Surveillance (WES). A method of monitoring pathogens in community wastewater flowing through organised and unorganised sewerage systems, WES detects pathogens shed via the infected human's gastrointestinal tract to assess the impending disease burden in the community. Its fingerprint is its proactive approach to detecting infections, as opposed to most other clinical methods that are reactive in nature.
Why is it gaining attention?
WES isn't new. In India, it was first employed in Mumbai in 2001 to detect polio. Globally, as well, Polio WES has been functional for a very long time. However, beyond polio, the method of WES gained substantive momentum during the coronavirus pandemic, when its benefits in early detection of variants started to be widely recognised across the globe. As a result, many countries such as the United States of America, Australia, the United Kingdom, Canada and South Africa integrated WES into their national disease surveillance efforts. Likewise, in low- and middle-income countries (LMICs), comprising Bangladesh, India, Pakistan and beyond, WES initiatives started gaining traction. In India, during the COVID-19 pandemic, WES activities picked up in various cities such as Gandhinagar, Ahmedabad, Bengaluru, Vellore, Pune and Hyderabad, to name a few. But its scope is not limited to COVID-19. WES has demonstrated widespread utility and scope as an early warning system for major infectious diseases–from aiding in the timely detection of disease outbreaks, estimation of underlying disease burden and disease transmission, to determination of genomic variants.
WES can potentially help monitor Poliovirus, SARS-CoV-2, Salmonella typhi, Influenza A and B, Respiratory Syncytial Virus (RSV), Vibrio cholerae, Measles virus, Hepatitis A and E, and various other pathogens that eventually find their way into the gastrointestinal tract from the site they infect first in our bodies. WES is also increasingly being used in testing for antimicrobial resistance (AMR).
[This article has been reproduced with permission from the Indian School of Business, India]
