Your town's sewage can tell you if a coronavirus outbreak is imminent, say researchers
Scientists detected traces of the new coronavirus in the sewage system of a Dutch city, even before the city reported its first case. This points to the possibility of using sewage surveillance to catch the new coronavirus early — before it gains a foothold in a community.
“The detection of the virus in sewage, even when the COVID-19 prevalence is low, indicates that sewage surveillance could be a sensitive tool to monitor the circulation of the virus in the population,” researchers wrote in their preprint study. It has another benefit: it could warn scientists if the new coronavirus is remerging in a city, they add.
Recently, American researchers said they were exploring whether a community's wastewater can help serve as an early warning system. Studies have shown that infected patients release the virus in the feces. The human waste, in turn, enter the sewage system, helping scientists detect the traces of the virus.
This is not the first time scientists have touted the idea. Earlier, scientists said they can turn to sewage systems to warn about impending outbreaks such as Hepatitis A Virus or Norovirus Outbreaks. Israel used this method to fight Polio.
In the new study, the Dutch team tested sewage samples from seven cities. They found the new coronavirus's genetic material at a wastewater treatment plant in Amersfoort and four other cities on March 5. Amersfoort had not reported any case until then.
“It is important to collect information about the occurrence and fate of this new virus in sewage to understand if there is no risk to sewage workers, but also to determine if sewage surveillance could be used to monitor the circulation of SARS-CoV-2 in our communities,” the study authors wrote. “That could complement current clinical surveillance, which is limited to the COVID-19 patients with the most severe symptoms," they added.
US researchers from the University of Michigan and Stanford University said sewage surveillance will also help them track the spread of the disease within a community.
"One of the key areas we’re exploring is whether we can detect this new virus, SARS-CoV-2, in a community’s wastewater before it’s known to be circulating there,” Project leader Krista Wigginton, from University of Michigan, said in a statement.
She explained that looking for the virus in wastewater might paint a different picture of the virus prevalence. “The case numbers we’re seeing reported in the US and lots of other places are dependent on how many test kits we have. So the curve displaying the number of cases is more of a curve of test kit availability in a community. What we see in wastewater may look different," she explained.
Their work could help epidemiologists, who are responsible for studying and analyzing the distribution and possible control of diseases. “We could identify areas with rapidly increasing cases as a warning system to the health care system. Finally, these numbers can help epidemiologists model the trajectory of the pandemic with far less testing burden on our health care system," Nasa Sinnott-Armstrong, a doctoral student at Stanford working on the project, said.