The University of Guelph is developing a COVID-19 early warning system that will sample and test waste water from its student residences.
The virus can be detected in human waste up to a week before individuals develop symptoms, according to the Guelph scientists behind the project. Some of those who get the disease, particularly young people, don’t ever develop symptoms, making them more likely to unknowingly spread the virus.
The hope is that by detecting elevated levels of COVID-19 in the sewer system, the university will be able to identify virus hot spots and take action to mitigate spread. That could include encouraging everyone to be tested or reinforcing practices known to slow transmission, such as masking, handwashing and physical distancing.
The university said it believes the project is the first of its kind on a Canadian campus, and could have applications at the broader neighbourhood or population level.
Lawrence Goodridge, director of the Canadian Research Institute for Food Safety at Guelph, said the testing will be carried out in his lab.
“If you can isolate waste water from a single dormitory and find the signal, that means at least one person in that building is potentially infected, but it doesn’t tell you who that is. So then you do individual testing of the students and potentially stop the outbreak from getting larger,” Prof. Goodridge said.
The key is monitoring the results over time to detect spikes that differ from the norm, he said.
“I expect that this will become much more important as the pandemic rages on, because people begin to loosen their resolve. Also, as influenza season kicks in and you see people with symptoms that could be COVID or flu, this could help tease it out,” Prof. Goodridge said.
The team of researchers at Guelph will be collecting samples from the waste water system connected to five university residences. About 2,000 people are living in the residences, according to the researchers, and each building’s waste water can be accessed from a manhole above a sewer to gather samples.
The team took samples before students arrived in September in order to establish a baseline. It will be sharing its work with the Public Health Agency of Canada and with a lab based in Quebec.
Similar initiatives have been launched at universities in the United States, including the University of Arizona, where it has been credited with helping stop a potential outbreak. Two cases where students in dormitories were not showing symptoms were caught thanks to waste water monitoring.
Ed McBean, a professor of engineering at Guelph, said the sampling will be done three times a week at three different times of day. Over time, the pattern in the data will become clear and the divergences that indicate an outbreak will be easier to spot.
“The university is interested in knowing if they have a problem in a particular building,” Prof. McBean said. “It’s trying to be pro-active and protect people, and this is one way to do it.”
At the moment, Prof. McBean said, many carriers aren’t found by public-health tracing, and an increasing share of positive tests are coming from younger age categories. This system may be able to effectively target those who need to be encouraged to go for testing.
More broadly, waste water testing could be used to detect neighbourhoods in a particular region or city where the virus may be spread, Prof. Goodridge said. A pilot project along those lines to monitor waste water was announced in British Columbia earlier this year.
“We know from this summer in Toronto and Montreal that the virus was not increasing equally in all regions of the city. So you could potentially pinpoint those regions and do sampling,” Prof. Goodridge said. “This can be used as additional information about opening or closing certain spots, given the province has said a complete shutdown is unlikely."
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