| Literature DB >> 34756912 |
Shelley W Peterson1, Ravinder Lidder1, Jade Daigle1, Quinn Wonitowy1, Codey Dueck1, Audra Nagasawa2, Michael R Mulvey3, Chand S Mangat4.
Abstract
SARS-CoV-2 variants of concern (VoC) have been increasingly detected in clinical surveillance in Canada and internationally. These VoC are associated with higher transmissibility rates and in some cases, increased mortality. In this work we present a national wastewater survey of the distribution of three SARS-CoV-2 mutations found in the B.1.1.7 (alpha), B.1.351 (beta), and P.1 (gamma) VoC, namely the S-gene 69-70 deletion, N501Y mutation, and N-gene D3L. RT-qPCR allelic discrimination assays were sufficiently sensitive and specific for detection and relative quantitation of SARS-CoV-2 variants in wastewater to allow for rapid population-level screening and surveillance. We tested 261 samples collected from 5 Canadian cities (Vancouver, Edmonton, Toronto, Montreal, and Halifax) and 6 communities in the Northwest Territories from February 16th to March 28th, 2021. VoC were not detected in the Territorial communities, suggesting the absence of VoC SARS-CoV-2 cases in those communities. Percentage of variant remained low throughout the study period in the majority of the sites tested, however the Toronto sites showed a marked increase from ~25% to ~75% over the study period. The results of this study highlight the utility of population level molecular surveillance of SARS-CoV-2 VoC using wastewater. Wastewater monitoring for VoC can be a powerful tool in informing public health responses, including monitoring trends independent of clinical surveillance and providing early warning to communities. CrownEntities:
Keywords: B.1.1.7; SARS-CoV-2; Variant; Wastewater; qPCR
Mesh:
Substances:
Year: 2021 PMID: 34756912 PMCID: PMC8552806 DOI: 10.1016/j.scitotenv.2021.151283
Source DB: PubMed Journal: Sci Total Environ ISSN: 0048-9697 Impact factor: 10.753
SARS-CoV-2 RT-qPCR allelic discrimination primers and probes.
| Target | Primer/probe | Primer sequence | Product length | Probe | Sequence | Reference |
|---|---|---|---|---|---|---|
| N1 | F | GACCCCAAAATCAGCGAAAT | 71 | Universal | FAM-ACCCCGCATTACGTTTGGTGGACC-MGB | CDC, 2020 |
| R | TCTGGTTACTGCCAGTTGAATCTG | |||||
| N501Y | F | CGGTAGCACACCTTGTAATGG | 144 | WT | FAM-ACCCACT | This study |
| R | GTTGCTGGTGCATGTAGAAGTTC | Variant | FAM-ACCCACT | |||
| Sdel69–70 | F | CATTCAACTCAGGACTTGTTCTTACC | 110 | WT | FAM-ATGCTAT | This study |
| R | GGTAGGACAGGGTTATCAAACCTC | Variant | FAM-TCCATGCTATCTCTG-MGB | |||
| N D3L | F | TTAGAGTATCATGACGTTCGTGTTG | 94 | WT | FAM-AATGTCT | This study |
| R | GGTGCATTTCGCTGATTTTGG | Variant | FAM-AATGTCT |
https://www.cdc.gov/coronavirus/2019-ncov/lab/rt-pcr-panel-primer-probes.html
Standard curve summaries for RT-qPCR SARS-CoV-2 variant detection and the CDC N1 assay. PCR efficiency and y-intercept cycle threshold (Ct) values were calculated for each of the primer-probe sets against tenfold dilutions of the corresponding DNA oligonucleotides. N1 was tested with both the WT and B.1.1.7 oligonucleotides.
| Sdel WT | Sdel V | SN501Y WT | SN501Y V | ND3L WT | N1 (WT template) | ND3L V | N1 (V template) | |
|---|---|---|---|---|---|---|---|---|
| Slope | −3.43 | −3.36 | −3.56 | −3.39 | −3.47 | −3.57 | −3.28 | −3.34 |
| Intercept | 38.60 | 37.88 | 39.70 | 38.76 | 38.26 | 36.65 | 37.48 | 35.75 |
| RSQ | 1.000 | 0.996 | 0.994 | 0.999 | 0.997 | 1.000 | 0.999 | 0.998 |
| Efficiency | 95.54 | 98.40 | 90.89 | 97.16 | 94.27 | 90.48 | 101.67 | 99.28 |
Fig. 1Standard curves for RT-qPCR SARS-CoV-2 variant assays against tenfold dilutions of DNA oligonucleotide controls with either the wild-type (WT) or B.1.1.7 (V) genotype in the presence of 100, 500, and 100 copies/μL of the alternate genotype for each locus.
Fig. 2Percentage of SARS-CoV-2 variant alleles detected using RT-qPCR in wastewater across Canada from February 16 to March 28, 2021.