Wastewater studies in three Sask. cities show COVID-19 levels continue to rise

COVID-19 viral loads are rising once again in the wastewater of several Saskatchewan cities, the most recent data from the University of Saskatchewan shows.

Since the summer of 2020, a group of researchers from the U of S have analyzed wastewater samples from Saskatoon, North Battleford and Prince Albert in search of traces of the COVID-19 virus.

Prince Albert data from the latest reporting period, which goes up to Sept. 12, showed a 66.2 per cent week-over-week increase in SARS-CoV-2 viral RNA load in the city's wastewater.

The data is based on the averages of three daily measurements during the reporting period, and shows the third highest value ever reported since the study began two years ago.

Wastewater project manager Femi Oloye says the higher increase in the city compared with the recent findings in Saskatoon is also related Prince Albert's size.

"Prince Albert is a small community," Oloye said. "Any little change will make the number ... very high compared to maybe Saskatoon, for instance."

Findings in North Battleford and Saskatoon

In North Battleford the viral RNA load climbed by 12.4 per cent in the reporting period up to Sept. 9, while researchers reported an increase of 1.6 per cent in Saskatoon for the reporting period up to last Wednesday.

In the latest weekly report, both cities saw their fourth highest COVID-19 values measured in the wastewater since the beginning of the U of S study during the pandemic.

As the small increase indicates, numbers are considered static in Saskatoon compared with the viral load measure during the previous reporting period, according to the latest data.

However, the report said the increase still indicates a rise in infections in the city, "which is consistent with the overall trend over the last month."

"Last week we saw a very high increase [in Saskatoon], and I was thinking within myself that there would be a possibility that it will go down this week, and it didn't go down," Oloye said.

"Sometimes maybe it is just one individual or [a] few individuals that caused the increase … [and] as they recovered, the viral load may come down. But if it's not just a few individuals, the viral load will stay … up for a few weeks, so that is what I think we saw in Saskatoon."

The concentration of viral particles in all three cities are considered "large", the report said, because they are greater than the ten-week averages recorded.

Most people who have the disease start shedding the COVID-19 virus through their feces within 24 hours of being infected, said the Global Institute for Water Security on its website.

An increase in viral load detected in wastewater indicates a hike of infections in the cities the samples were taken in.

Oloye says the new figures are a reminder to be careful and follow COVID-19 regulations.

"What we have been seeing is the trend is going up in the three cities we are monitoring," he said.

"One of the reasons, I think, why we're having things like that is because we are opening up and people are beginning to forget that COVID has not gone."