The Key to Tracking Coronavirus Could Be Your Poo

Sewage surveillance could help scientists predict new outbreaks

We won’t have to shelter from the new coronavirus forever. In fact, we may be able to briefly return to public life this summer, according to The Atlantic. But several predictors of Covid-19 outbreaks suggest the virus could be seasonal, returning with fury in the fall. It is likely that several periods of social distancing will be necessary for containing the virus until a vaccine for SARS-CoV-2, the virus that causes Covid-19, is widely available, which could take a year or more.

How will folks know when it’s safe to come out and when to go back indoors? There may be clues in our sewage.

Dozens of scientists across the globe are sampling poo to find tiny shreds of the coronavirus that can serve as an early warning of outbreaks. In theory, if viral levels reach a certain threshold, health experts can tell more people to stay home. When viral loads abate, they can tell people it’s okay to fraternize.

Last week, Dutch scientists announced a first-of-its-kind method for detecting SARS-CoV-2 in wastewater. The team, from KWR Water Research Institute, took samples of wastewater from six Dutch cities as well as Amsterdam’s airport in February 2020, weeks before the Netherlands announced its first case of Covid-19. They collected new samples and repeated the experiment in the first and third weeks of March.

After running the sewage samples through a centrifuge, the scientists looked for four genetic signatures of SARS-CoV-2. Three were from the nucleocapsid (N) gene, which builds proteins that make up the core of the virus. The remaining gene encodes the envelope (E) protein, which the virus uses to reproduce.

In the February samples, the researchers found no sign of coronavirus. But by early March, some of the results came back positive. All but one of the samples taken in the third week of March samples came back positive, with bits of the N and E genes.

In the city of Amersfoort, the team was able to detect SARS-CoV-2 before any cases had been announced locally. These results were published before peer review on MedRxiv.