U of S wastewater study foreshadows a COVID-19 surge

Saskatoon is leading the province in active COVID-19 cases and that trend may continue.

The most recent study from the Global Institute for Water Security at the University of Saskatchewan revealed the largest spike of viral traces in the wastewater since the group began tracking last summer.

From July 29 to Aug. 4, the viral RNA load in the city’s wastewater was over 50,000, an increase of 118 per cent compared to the previous week.

Markus Brinkmann, a toxicologist and a member of the research team, said the results are worrisome.

“That means there is virus circulating in the community. That means there is a high risk of being infected,” he said. “We do think that this might actually foreshadow a little bit of an increase.”

The data also shows the Delta variant has become the dominant strain in the wastewater samples.

However, Brinkmann said the data needs to be taken into context.

“We know patients infected with that variant of concern shed higher particles of the virus,” he said. “That means the levels that we see in the wastewater are not necessarily comparable to levels before Delta arrived.”

Saskatoon’s active COVID-19 caseload has tripled since July 27. As of Monday, the city had 152 active cases, four times as many as Regina.

Most people with COVID-19 start shedding virus particles through their feces within 24 hours of being infected. Brinkmann says cases typically start showing up seven to 10 days after samples are collected.

“With the arrival of the variants, everything has become more chaotic in the wastewater,” he said. “If we see the viral load double, we don’t necessarily predict any more cases would also double in the subsequent week, but it certainly indicates a risk for an increase.”