STIRLING, Scotland — We already know that the coronavirus can spread in a multitude of ways, from aerosol droplets to infected surfaces, but a new study is warning that the possibility of COVID-19 spreading via sewage “must not be neglected.”
“We know that COVID-19 is spread through droplets from coughs and sneezes, or via objects or materials that carry infection. However, it has recently been confirmed that the virus can also be found in human faeces – up to 33 days after the patient has tested negative for the respiratory symptoms of COVID-19,” explains lead study author Professor Richard Quilliam of Stirling University in a release.
Professor Quilliam believes sewage systems all over the world may pose a serious transmission risk, and one that maintains contagiousness far longer than other infection routes. The entire team behind this study believe an “an investment of resources” should be allocated to investigate this matter.
“It is not yet known whether the virus can be transmitted via the fecal oral route, however, we know that viral shedding from the digestive system can last longer than shedding from the respiratory tract. Therefore, this could be an important – but as yet unquantified – pathway for increased exposure,” he adds.
The SARS virus that emerged in China close to 20 years ago was indeed detected in sewage discharged by two Chinese hospitals at the time, so this theory isn’t without precedent. However, regarding COVID-19, since most people infected with the virus probably won’t end up visiting a hospital, Professor Quilliam is concerned that the coronavirus could extensively infiltrate the world’s sewers on a “widespread” scale.
Since countless coronavirus cases are going untested, it’s difficult to predict the spread of COVID-19 in waste systems, as well as the public health implications of the coronavirus making its way to wastewater treatment centers. It’s even harder to say how the coronavirus will impact the environment as a whole once it is discharged from sewage systems.
The structural makeup of COVID-19’s lipids indicate the virus will behave differently than other viruses in an aquatic environment. It’s still unknown just how long COVID-19 may be able to survive in an environment like a sewage system, but other coronaviruses have been known to persist for up to 14 days in sewers.
“The transport of coronaviruses in water could increase the potential for the virus to become aerosolized, particularly during the pumping of wastewater through sewerage systems, at the wastewater treatment works, and during its discharge and the subsequent transport through the catchment drainage network,” the study reads, regarding the possibility of human exposure to contaminated waste.
“Atmospheric loading of coronaviruses in water droplets from wastewater is poorly understood but could provide a more direct respiratory route for human exposure, particularly at sewage pumping stations, wastewater treatment works and near waterways that are receiving wastewater,” the authors note.
Of course, the sewage risks of COVID-19 are that much more worrisome in areas of the world where open defecation is a regular occurrence, or regions lacking in adequate sanitation systems. In these locations, waterways are used as both sewers and water transportation routes for homes and bathrooms.
“Such settings are commonly accompanied by poorly resourced and fragile healthcare systems, thus amplifying both exposure risk and potential mortality,” the authors explain.
As of today, the only available information on COVID-19 in fecal matter is limited to hospital settings.
“In the immediate future, there needs to be an investment of resources to improve our understanding of the risks associated with fecal transmission of SARS-CoV-2, and whether this respiratory virus can be disseminated by enteric transmission,” the study concludes. “At a time when the world is so focused on the respiratory pathways of a respiratory virus, understanding the opportunities for SARS-CoV-2 to be spread by the fecal-oral route must not be neglected.”
The study is published in Environmental International.