A groundbreaking study has demonstrated that a city's sewage system can function as a giant public-health scanner, revealing circulating viruses long before they appear in clinics. Researchers from Gujarat Biotechnology Research Centre (GBRC), Gujarat Technological University (GTU), and Gujarat Biotechnology University (GBU) conducted a year-long wastewater surveillance in Ahmedabad, Gandhinagar, Vadodara, and Rajkot, uncovering 170 DNA and 135 RNA virus species.
Viruses Detected
The detected viruses included Covid-19, adenovirus, influenza, hepatitis, and rotavirus. The study also highlighted a vast diversity in strains specific to animal and human sources, emphasizing the potential for zoonotic disease monitoring.
Early Warning System
Healthcare experts noted that wastewater surveillance is used globally as an early warning system. During the Covid-19 pandemic, spikes in wastewater viral levels preceded increases in hospital cases, showcasing its predictive power.
Methodology
Researchers collected wastewater samples every two weeks for a year from 24 sewage treatment plants and pumping stations serving an estimated 1.65 crore people. This allowed them to capture viral diversity and seasonal variations across the four cities.
City-Specific Findings
The study revealed distinct viral prevalence patterns: Astroviridae in Vadodara, Adenoviridae in Rajkot, Polyomaviridae in Gandhinagar, and Parvoviridae in Ahmedabad. SARS-CoV-2 was consistently detected in Gandhinagar and Rajkot, with highest prevalence in Vadodara, followed by Ahmedabad. Chicken anemia virus and Avian gyrovirus 2 were more prevalent in Ahmedabad, along with Luteoviridae, Flaviviridae, and Hepeviridae, indicating both human and animal virus circulation.
Health Implications
City-based physicians explained that astrovirus causes diarrhoea, adenovirus affects respiratory, eye, and gastrointestinal tracts, parvovirus causes flu in children, and polyomavirus attacks immunocompromised individuals. The study compared wastewater data with lab results and prevalent trends, further validating the method's usefulness.
Call for Action
Public health experts urged sharing wastewater data with health departments and city administrations to enable timely interventions, especially for zoonotic diseases under the One Health concept. The study, published in Nature Portfolio Journal Emerging Contaminants, underscores the potential of wastewater surveillance for community health monitoring.
