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Detection of COVID-19 in Stockholm sewage is first step toward early-warning system

Published May 05, 2020

Development of an early warning system for COVID-19 outbreaks continues to move forward. Researchers at KTH reported they have successfully isolated and concentrated coronavirus RNA from wastewater samples in Stockholm.

Zeynep Cetecioglu Gurol, researcher at KTH, works in the lab where they are developing the early warning system for further COVID-19 outbreaks.

Zeynep Cetecioglu Gurol, a microbiologist and wastewater engineer at KTH, says that traces of the virus were measured in each of the four random samples of wastewater collected at two Stockholm water treatment plants between April 6 and April 26 .

The virus is transmitted into the sewage system mainly through feces. While the measurement reveal the effectiveness of the detection method, it is still too early for the researchers to draw conclusions about the spread of the virus in the population.

The researchers’ preliminary assessment indicates that the Bromma treatment plan, serving the northern part of the city, appears to have had more virus than the Henriksdal plant, which serves the southern part of the city. The virus appears to have increased in Henriksdal between the first and the second sampling.

“We need to test more, and we need more time to verify the numbers and what they tell us,” Cetecioglu Gurol says. “In order to do that we need to analyze more samples and have a bigger data set.”

Wastewater samples collected from Stockholm's sewage treatment plants.

It may be possible to have such a system running within a matter of weeks, but how quickly the system comes together depends on more water testing and correlating the readings with public health data, says David Nilsson, director of KTH’s Water Centre, which is co-funding the project along with the Department of Chemical Engineering and the Department of Sustainable Development, Environmental Sciences and Engineering (SEED) at KTH.

The next steps are to continue gathering samples, and to optimize the range of the sampling instrument, Nilsson says. The researchers are also waiting for wastewater samples from Spain and Italy, which will be important for the design of the early-warning system.

“This is just the first step in a long walk,” Nilsson says.

“But considering that only a few weeks ago we did not do these kinds of analyses, we had no method, it’s quite an achievement,” he says. “If we can keep up the pace, we’re pretty hopeful.”

David Callahan

Follow COVID-19 monitoring at the Water Centre website

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Last changed: May 05, 2020