Is coronavirus in wastewater a public well being threat?

An international group of environmental experts assessed the possible public health effects of SARS-CoV-2 in wastewater.

Public health strategies to combat the COVID-19 pandemic aim to reduce the spread of the highly contagious SARS-CoV-2 virus. The main mode of transmission of the virus is through close personal contact through respiratory droplets, aerosols, and mutual surface contact – but there can be additional sources of spread.

During the SARS-CoV-1 outbreak in 2003, evidence from a number of cases in a block of flats suggested that the virus could spread through contaminated sewage, either through breathing aerosols, from flushing toilets or through faulty plumbing systems arise. SARS-CoV-2 is also found in fecal samples from infected people, and there is concern that the virus could spread indirectly via sewage systems. An international group of environmental experts assessed the current findings on coronavirus in wastewater, considering the risks to public health and areas for future research. Your assessment will be published in Nature Sustainability.

Coronavirus in wastewater can be an indirect mode of transmission

The researchers evaluated a wide range of evidence related to SARS-CoV-2 in wastewater, including: the possible sources of the virus; Detection methods, infectivity and survival of the virus in wastewater; Potential for dissemination in sewage systems; and virus dispersion by irrigation of plants with treated wastewater or in surface water and groundwater. They also reviewed recent surveillance of COVID-19 outbreaks using wastewater monitoring and looked at the effectiveness of conventional and advanced water treatment methods in reducing the spread of viruses.

The findings so far indicate that infectious SARS-CoV-2 virus particles can be detected in wastewater and possibly spread through wastewater systems that enter natural watercourses, or through poorly treated wastewater that is used to irrigate plants or replenish Recreational water systems such as lakes and bodies of water are used rivers. The researchers point out that 3.5 billion people worldwide use unsafe sanitation and this enables the transmission of many viral diseases including SARS-CoV-2. This could be a particularly important factor in the spread of the COVID-19 pandemic in low-income countries.

Even in developed countries, traditional wastewater treatment practices may not be enough to remove or inactivate viruses like SARS-CoV-2 and this requires urgent further investigation. The introduction of more advanced wastewater treatments such as low pressure or high pressure membrane filtration technologies can provide a complete barrier to SARS-CoV-2 and other viruses.

Monitoring SARS-CoV-2 levels in sewage systems was recently proposed as a tool to help identify COVID-19 outbreaks in the community in addition to individual COVID-19 testing programs. Wastewater monitoring could give an early warning signal for an outbreak, as changes in SARS-CoV-2 concentrations in wastewater can precede changes in confirmed COVID-19 case numbers by several days. This would allow appropriate public health restrictions to be put in place at an early stage. This can be especially useful for monitoring communities with a previous COVID-19 outbreak.

Urgent need for further investigation of coronavirus in wastewater

The experts concluded that there is already enough evidence of how the coronavirus in wastewater affects the risk to public health. "Can sewage contain enough coronavirus to infect people? The simple truth is that we don't know enough and that this needs to be fixed as soon as possible, ”said Dr. Edo Bar-Zeev of the Zuckerberg Institute at Ben Gurion University, the lead author of the study.

The authors recommend urgent studies to determine the risk in different country populations, including extensive studies on the frequency of detection of SARS-CoV-2 in wastewater and to identify and mitigate the risks of SARS-CoV-2 transmission via waterways. They also recommend sewage treatment plants update their treatment protocols to ensure successful virus removal. These approaches will not only help contain the COVID-19 pandemic, but future viral disease outbreaks as well.

Written by Julie McShane, MA MB BS

References:

1. Bogler A., ​​Packman A., Furman A. et al. Rethink and monitor wastewater risks in the light of the COVID-19 pandemic. Sustainability of Nature (published online on August 19, 2020).

2. American Associates, Ben Gurion University of the Negev. Press releases from August 24, 2020. Could COVID-19 be contagious in wastewater? https://www.eurekalert.org/pub_releases/2020-08/aabu-cci082320.php

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