Emergence of SARS-CoV-2 in wastewater: Inspection through Wastewater-based Epidemiology essential for India

Figure 1: Possible strategy to minimize community spreading of COVID-19 through faecal-oral transmission 


Many countries are tackling the spread of the contagious disease COVID-19 by screening, testing, and implementing social distancing norms and lockdowns to avoid community transmission. The reported mode of infection of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) is respiratory droplet and contact routes from the infected person. Countries worldwide have also reported the presence of SARS-CoV-2 fragments in stool samples from China (Pan et al.; Zheng et al. 2020); Netherland (Wan et al.; Medema et al. 2020); USA (Holshue et al. 2020). Stools of asymptomatic patients also tested positive for the viral fragments. Investigation of the occurrence of SARS-CoV-2 RNA in wastewater showed positive results in various studies conducted in Spain (Randazzo et al. 2020); Australia (Ahmed et al. 2020); France (Wurtzer et al. 2020); Italy (La Rosa et al. 2020); India (Kumar et al. 2020); United States (Peccia et al.; Wu et al. 2020); Pakistan (Sharif et al. 2020); etc.

The presence of SARS-CoV-2 fragments in wastewater is a great matter of concern for India also. As only 37.18% of the total wastewater generated gets treated while remaining is released in various surface water bodies. Prior research reveals that the human coronavirus can remain infectious for several days in sewage. Viral contaminated water is a potential source of aerosolization of the virus and direct human exposure (Casanova et al. 2009). A study conducted at Amoy Gardens, Hong Kong suggested an outbreak of SARS 2003 from the leakage of sewage pipe which led to the formation of aerosols of water droplets comprising the coronavirus which is the possible reason for the community spread of the disease in the Apartment. According to Zheng et al. 2020, the viral load in stool samples was found higher than the respiratory and blood serum samples analysis suggesting the possible persistence of viral shedding in wastewater. He concluded that the viral load of SARS-CoV-2 in stool specimens easily reached a high level and rebounded even though respiratory signals became negative.

Developing countries like India require to adapt environmental surveillance like Waste Water-based Epidemiology tools to tackle such conditions. The viral load in wastewater would increase with an increasing number of cases in India. India's inability to treat the whole wastewater generated through common wastewater treatment facility centres is a major cause of concern to decide the further extent of the disease. Drainage, sewer systems, etc. exposed directly in the immediate atmosphere at various regions increase the chances of the spread of the disease through improper defecation systems. All the common Wastewater Treatment Facilities (WWTP) need regular monitoring; also the current procedure needs to be revisited for complete removal of SARS-CoV-2 fragments.

The way forward to limit the spread of the disease is Environmental Surveillance through Wastewater Based Epidemiology (WBE) at the State level. It could perform the function of preliminary indicator to predict the next surge of COVID-19 pandemic. Decision-makers and policy framers require to revise policy guidelines to ensure that wastewater is treated as per the demand of the COVID-19 situation. Safety measures for the home quarantined, quarantine centre individuals, etc. need to be devised. Sanitation workers and wastewater treatment facility staff should be provided with proper personal protection equipment (PPE). Integration of fecal/stool testing for SARS-CoV-2 RNA is crucial for informing the precautions necessary to prevent transmission in patients with SARS-CoV-2 infection.



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Madhulika Bhati1 and Madhur D. Gajbhiye2

1. CSIR-National Institute of Science, Technology and Development Studies (CSIR-NISTADS),

    New Delhi
2. School of Environmental Science, Jawaharlal Nehru University, New Delhi Corresponding

    author email: madhulikabhati@nistads.res.in