For the dormitory project, the team used a passive sample collection system that provided round-the-clock monitoring of wastewater, maximizing chances of capturing COVID-19-linked genetic material. The system used 3D-printed cigar-shaped devices, known as torpedo samplers, that were placed inside the wastewater flow, accumulating viral RNA samples over at least 24 hours.
Inside these tubes were membranes that attract RNA, with cotton swabs to grab some of the particulates. USask Facilities staff gathered samples five days a week for eight months by accessing the tubes through manholes near the dorms. Researchers used a platform provided by the partner company, LuminUltra, to determine the amount of RNA in the samples to measure the prevalence of COVID-19.
The team’s work published this month in a paper in Elsevier’s journal, Science of the Total Environment, shows that such passive sampling of wastewater is useful for monitoring COVID-19, or other viral illnesses in a small population, said Dr. Markus Brinkmann (PhD), co-author and associate professor in USask’s School of Environment and Sustainability.
“This a great story of an integrated program, where everyone from USask administrators in the Pandemic Response Team, to us as researchers, to the folks in Facilities, came together to fill the need to keep students safe quickly,” said Brinkmann.
Researchers compared the results of their passive surveillance process with residence and campus-wide daily self-reported COVID-19 cases. As well, the campus results were compared with the City of Saskatoon Wastewater Treatment Plant viral loads, starting in August 2021.
“The spread of COVID-19 in the USask residences and general population closely followed the trends of the local and surrounding communities,” said Dr. Kerry McPhedran (PhD), co-author and associate professor in USask’s College of Engineering.
“These similarities indicate the usefulness and cost-effectiveness of monitoring the spread of COVID-19 in small-scale communities using wastewater-based surveillance,” he said.
This project points to the robustness of the process of employing passive sampling and using off-the-shelf, relatively inexpensive instruments available from companies such as LuminUltra and Cepheid (GeneXpert) for small-scale monitoring applications, said Brinkmann.
“I think for some employers and for places such as USask, where lots of people came together to work, learn, and live, it was smart to apply this technology while other sources of information were unavailable. In the big scheme of things, it was fairly cheap,” he said. “One could actually respond in almost real-time to changes in our community COVID-19 prevalence.”
McPhedran said the method could be used to track the prevalence of other viruses, such as regular flu or a range of other respiratory diseases, if the logistics can be made to work for extending monitoring to the entire campus, not simply the residences, if the need arises in the future.
Other contributors to the paper are: USask undergraduate students Saanvi Mital and Annisa Ilias; Daniel Hamilton, PhD student in the College of Engineering; and Niteesh Jain, research assistant in engineering.
Link to the paper: https://authors.elsevier.com/a/1fif5B8ccuqec