Testing specificity and sensitivity of wastewater-based epidemiology for detecting SARS-CoV-2 in four communities on Vancouver Island, Canada
Date
2022
Authors
Masri, Nadia Zeina
Card, Kiffer George
Caws, Emmanuelle A.
Babcock, Alana
Powell, Ryan
Lowe, Christopher J.
Donovan, Shelley
Norum, Shelley
Lyons, Shirley
De Pol, Sean
Journal Title
Journal ISSN
Volume Title
Publisher
Environmental Advances
Abstract
We report wastewater surveillance of the spread of SARS-CoV-2 based upon 24-h composite influent samples taken weekly from four wastewater treatment plants (WWTP) on Vancouver Island, BC, Canada between January 3, 2021 and July 10, 2021. Samples were analyzed by reverse transcription quantitative polymerase chain reaction targeting the N1 and N2 gene fragments of SARS-CoV-2 and a region of the replication associate protein of the pepper mottle mosaic virus (PMMoV) serving as endemic control. Only a small proportion of samples had quantifiable levels of N1 or N2. Overall case rates are weakly correlated with the concentration (gene copies/L) and with the flux of viral material influent to the WWTP (gene copies/day); the latter accounts for influent flow variations. Poisson multimodal rank correlation accounts for differences between the four WWTP and shows a significant correlation with a significant positive intercept. Receiver operator characteristics (ROC) analysis confirms a cut-off of cases based on amplified/not-amplified experimental data. At the optimal cut point of 19 (N1) or 17 (N2) cases/week/100,000 the sensitivity and specificity is about 75% for N1 and 67% for N2.
Description
The authors gratefully acknowledge the active sampling and logistical support of the Capital Regional District (Crystal Fudge & McLoughlin Point/Saanich Peninsula WWTP operations staff) and the Regional District of Nanaimo, and the Vancouver Island Health Authority for providing epidemiological data. Scott Meschke (UWash), Ryan Ziels (UBC), Natalie Prystajecky (BCCDC), Melissa Glier (BCCDC), Kara Nelson (UC Berkeley) and their teams provided critical feedback in the early stages of methods development.
Alana Babcock, Josie Chrenek, Rebecca Kircsh, Jacob Morris and Daniel Wallis provided essential technical support in sample processing. Benjamin McClennon and Gordon Wong assisted with scripting to semiautomate the retrieval of information from instrument results files.
Keywords
pQCR, Sensitivity, Specificity, Wastewater-based epidemiology, Wastewater surveillance, SARS-CoV-2, Paper mild mottle virus, Centre for Advanced Materials and Related Technology (CAMTEC)
Citation
Masri, N. Z., Card, K. G., Caws, E. A., Babcock, A., Powell, R., Lowe, C. J., ... Buckley, H. L. (2022). Testing specificity and sensitivity of wastewater-based epidemiology for detecting SARS-CoV-2 in four communities on Vancouver Island, Canada. Environmental Advances, 9, 100310. https://doi.org/10.1016/j.envadv.2022.100310