Wastewater surveillance is an excellent tool to monitor the presence of specific pathogens well before they can be detected through laboratory testing. It has been routinely used for decades for tracking the polio virus in almost every country. Water-borne viruses can be best studied through testing sewage samples. If wastewater surveillance provides accurate information about the presence of polio virus excreted by humans, in the case of other pathogens, for instance SARS-CoV-2 virus, it helps provide information on new variants and virus load which serves as a proxy for the extent of virus spread in the community. The biggest advantage of wastewater surveillance is that it is cost-effective and can independently confirm the presence of pathogens before laboratory testing throws up a warning signal.
For instance, wastewater surveillance carried out by the Tata Institute for Genetics and Society (TIGS) in Bengaluru was able to detect a silent wave of the XBB.1.16 Omicron variant in the city last year. The virus variant began increasing in early-March last year and peaked on April 1.
With the usefulness of wastewater surveillance during the pandemic established, researchers in developed countries have used it for tracking other diseases such as monkeypox, influenza and cholera. In a paper published in November last year in the journal Science Translational Medicine, researchers in the U.S. have suggested that wastewater surveillance be expanded to track dengue, malaria, Zika and typhoid.
