Dutch scientists were able to find the coronavirus in a city’s wastewater before Covid-19 cases were reported, demonstrating a novel early warning system for the pneumonia-causing disease.
The so-called SARS-CoV-2 coronavirus is often excreted in an infected person’s stool. Although it’s unlikely that sewage will become an important route of transmission, the pathogen’s increasing circulation in communities will increase the amount of it flowing into sewer systems, Gertjan Medema and colleagues at the KWR Water Research Institute in Nieuwegein said on Monday.
They detected genetic material from the coronavirus at a wastewater treatment plant in Amersfoort on March 5, before any cases had been reported in the city, located about 50 kilometers (32 miles) southeast of Amsterdam. The Netherlands confirmed its first Covid-19 case on Feb. 27 and discovered health workers had fallen ill with the infection in a southern part of the country days later — a sign that it was spreading in the community.
“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,” Medema, the institute’s principal microbiologist, and co-authors said in a paper released ahead of peer review. “That could complement current clinical surveillance, which is limited to the Covid-19 patients with the most severe symptoms.”
It’s the first report of detection of SARS-CoV-2 in sewage, they said.
Wastewater surveillance is a well established method of detecting poliovirus and antibiotic-resistant bacteria, as well as the use of illicit and prescription medications.
Sewage surveillance could also serve as early warning of the emergence and re-emergence of Covid-19 in cities, the Dutch scientists said.
“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,” they said.