$ 1 device developed in Halifax that detects COVID-19 in sewers that attract global interest

A $ 1 device developed at Dalhousie University in Halifax that can detect COVID-19 in wastewater has been shipped across Canada and around the world to assist scientists and public health in the fight against deadly respiratory disease.

The device is a small, spherical cage that contains an absorbent pad for collecting samples from sewer systems. The samples are then analyzed using laboratory equipment to determine if COVID-19 is present in the wastewater.

Unlike previous wastewater testing methods for COVID-19, the cage — which is 3D-printed on Dalhousie — is inexpensive to make and costs around a buck.

The low cost of the device makes monitoring more accessible, says Graham Gagnon, one of the researchers and director of the Dalhousie University Center for Water Resource Studies. Although the equipment needed to analyze the wastewater is expensive, most COVID-19 test laboratories would already have it.

Dal researchers, including Emalie Hayes, a Ph.D. students who helped develop the device have sent about 150 of them to places as far away as Australia and the Sorbonne University in France. Others have been sent to the BC Center for Disease Control, the government of the Northwest Territories and public health agencies in Ontario.

“We were like, ‘Wow, we kind of hit the big time knowing that someone at the Sorbonne was interested in what we’re doing,” Gagnon said.

The Northwest Territories have used the cage in sewers outside public schools to monitor for COVID-19 and in one case discovered an occurrence, he added.

Public Health in Nova Scotia said it does not use wastewater tests to monitor COVID-19.

Predicts 3rd and 4th wave

Gagnon and his team have used other units to monitor four treatment plants in Halifax, Dartmouth, Mill Cove and Eastern Passage, which treat about 92 percent of the wastewater in the Halifax area.

They have installed the cages in sewers outside five studio apartments in Dalhousie, six elsewhere in HRM and a few communities in the province.

They are tested about three times a week, and if a unit gives a positive result, researchers run more frequent tests.

Erjavec uses the sewer cage outside Risley Hall, another residence at Dal. (Submitted by Graham Gagnon)

Gagnon said the tests are sensitive enough to detect about three cases of COVID-19 in a population of 100,000 and can detect the presence of COVID-19 about 10 to 14 days before public health agencies detect it.

By the time the third wave in Nova Scotia began to pick up speed in the third week of April 2021, scientists had already detected COVID-19 in the wastewater of Halifax since the end of the first week. They saw a huge increase in the presence of COVID-19 at all four treatment plants in late April, just over a week before the number of new daily cases increased.

The same thing happened as the fourth wave geared in late summer.

“At the end of August, we were like, ‘Oh, it’s interesting, we’re starting to see a signal again at the sewage plant.’ And then about two weeks later, there was a message that they were starting to see it again, ”Gagnon said.

Gagnon said he is unable to predict what the fourth wave will look like based on the test. So far, the pattern is less persistent than what he observed in the third wave, as he sees some days with spikes and others without.

Researcher Emalie Hayes checks the COSCa unit outside Howe Hall, a residence at Dalhousie University. (Submitted by Graham Gagnon)

He declined to say whether the tests outside the Dalhousie residences have found an increase in COVID-19 since a large student party off campus took place a few weeks ago.

Gagnon said the devices cannot accurately identify who may have COVID-19, but they are a quick and easy way to see if anyone in a defined population has it.

“We can cover more people for wastewater testing than could ever be from some kind of clinical trial,” he said.

Researchers are now considering other potential uses of the devices, including to detect algae flowers or bacteria such as E. coli.

Meanwhile, New Brunswick company LuminUltra is preparing to sell a device based on the device developed by Gagnon and his team by the end of this month.

Product Applications Director Jordan Schmidt said there is worldwide interest in the device because it is inexpensive, easy to use and provides a high-quality sample.

“The passive samplers are really good as a smoke detector,” Schmidt said. “So you know you can put them outside a nursing home or college … where you worry most is there COVID-19 or not?”

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