NORTH BATTLEFORD - There has been no shortage of reports throughout the pandemic about the amount of COVID-19 found in wastewater in the province.
The amount of virus found in Saskatoon wastewater has been used to predict upcoming virus infection spikes in that city, and now the same technology is being used to predict rising Delta variant numbers in North Battleford.
It is all part of the wastewater-based epidemiology testing for SARS-CoV-2 carried out by the University of Saskatchewan. Researchers John Giesy (Toxicology Centre and Western College of Veterinary Medicine) and Markus Brinkmann (School of Environment and Sustainability, Global Institute for Water Security, and Toxicology Centre), along with Dr. Kerry McPhedran, have been working during the pandemic to gather the information, which has proved valuable in predicting what might happen in the coming days and weeks.
According to the university, these results are considered a leading indicator of impending surges in case numbers, preceding increases in new positive cases by seven to 10 days.
McPhedran spoke to the News-Optimist/SASKTODAY.ca on Wednesday about the work that has gone on. They had been doing the wastewater monitoring in Saskatoon since last June, funded by the Public Health Agency of Canada and Global Water Futures at the University of Saskatchewan.
After an initial six-month funding, they were able to get their funding renewed and McPhedran said at was at that point that they decided to expand to North Battleford and Prince Albert.
“North Battleford we’ve been doing since the beginning of August and Prince Albert since the beginning of July,” said McPhedran. “So the same testing, the same kind of partnership – it’s just three municipalities instead of one.”
What they do is measure a viral load of wastewater which is normalized per 100 milliliters of wastewater.
“The population, it won’t matter - basically we can normalize it to the different populations,” McPhedran said.
“It’s kind of ironic – all three of the municipalities we do had really low loads until about a month ago, and that’s when they started to go up.”
A dashboard is available for the public to view at https://water.usask.ca/covid-19/#MeasuringVirusIndicatorsinWastewaterasanEarlyWarningofCOVID19Outbreaks. According to that dashboard, the numbers for Aug. 13 to 20 indicate a normalized wastewater virus load of 45,295/100 ml, an increase of 1,230 pe rcent week over week. Of that, 22,452/100 ml is the Delta variant – an increase of 850 percent.
The virus load in North Battleford is just about half what the virus load is in Prince Albert or Saskatoon. In Prince Albert from Aug. 16-23, the virus load is 104,815/100 ml of which 95,750/100 ml is the Delta variant. For Saskatoon from Aug. 18-25, the normalized virus load was 109,673/100 ml, of which 57,947/100 ml is Delta. Delta is up 580 per cent in Prince Albert but 54 per cent in Saskatoon.
According to the information on the dashboard, the sharp increase in viral RNA load for North Battleford is indicative of an increase in SARS-CoV-2 infections in the city. This may or may not be reflected by new case numbers in upcoming weeks.
As well, right now all of the variant viral RNA load in wastewater is contributed by the Delta (B.1.617) variant of concern. Viral RNA fragments of Alpha (B.1.1.7) and Gamma (P1) variants were not detected through their RT-qPCR screening.
A graph is also provided on the dashboard showing a major spike in virus numbers beginning between Aug. 15 to 19.
It had gone from the point where “we could almost not detect it in the wastewater, and then it went up quite a bit since then,” McPhedran said.
Based on that data, the prediction is that in five to seven days “we’ll have dramatic increases in case numbers,” said McPhedran. The virus will show up in the wastewater before symptoms develop in people, and before people decide to get tested. “That’s why the wastewater is about five to seven days ahead of where the case numbers would be,” he said.
“Basically the goal is, and they’ve been using this in Saskatoon, to help make decisions on what they are going to do five to seven days in advance,” said McPhedran.
According to the university’s dashboard: “Most people with COVID-19 start shedding SARS-CoV-2 through their stool within 24 hours of being infected. This “viral signal” detected in wastewater helps provide population-level estimates of the rate of infection in a municipality, indicating whether the number of infected people in a city is increasing, decreasing or staying the same. Even a few days of early warning in communities can be critical to the success of pandemic preparedness measures, especially for rapidly evolving variants.”
To collect the North Battleford data, the U of S researchers connected with Stewart Schafer, the city’s Director of City Operations, as well as Mark Keller who is Water and Wastewater Treatment Plants Superintendent.
The U of S team sent out kits to the city for sampling and personnel at the wastewater treatment plant take samples twice a week. Those samples are then put on ice and placed in coolers, and then sent back to the U of S researchers.
The samples arrive back typically on the same day, and then a report is prepared and sent to the city, as well as placed on the U of S dashboard for the public to see as well. The reports are sent out to the municipalities each week.
The help and co-operation of those at the Wastewater Treatment Plant has been crucial, McPhedran said.
“It’s really been a partnership with each of the municipalities and the people working there,” McPhedran said. “Without them, we don’t get samples.”
The testing of wastewater samples to determine loads of COVID-19 has been used throughout North America and the world over the course of the pandemic.
In fact, in Italy, “they actually take samples and keep them stored, and they were able to look back and see when the pandemic started from wastewater samples.”
Across Canada, there has been an investment made in collecting wastewater samples, McPhedran said, particularly in Ontario and Quebec. The researchers have been in communication with other communities across Canada as to what they are seeing.
“Every two weeks we actually have meetings on what’s going on across Canada and in the Territories. Basically each of those areas has had people that will talk and let us know what’s happening,” said McPhedran.
As for what people should take away from the latest numbers, McPhedran said the big thing is that wastewater viral loads are going up, so “that means people are infected. Whether they are vaccinated or not, they’re infected.”
“A lot of people were seeing if the case numbers went up, they were deciding whether they went to an event or not,” said McPhedran. “I know just today, Saskatoon actually mandated you have to wear masks in city-owned places and buses again.”
Also, while these samples also predict when the virus is going up, it also indicates when it will begin to decline.
“If this is the fourth wave, we’ve likely see a peak and then a decline,” Dr. McPhedran said. “That’s another good one – if we see a decline we know that things are getting better again. So it looks pessimistic when things are going up but optimistic when things are going down.”
