tetano
Editor, Senior Moderator
Sci Total Environ
. 2024 Jan 23:170345.
doi: 10.1016/j.scitotenv.2024.170345. Online ahead of print. Influences of 23 different equations used to calculate gene copies of SARS-CoV-2 during wastewater-based epidemiology
Mia G Ryon[SUP] 1 [/SUP], Laura M Langan[SUP] 2 [/SUP], Christopher Brennan[SUP] 3 [/SUP], Megan E O'Brien[SUP] 1 [/SUP], Fallon L Bain[SUP] 1 [/SUP], Aubree E Miller[SUP] 1 [/SUP], Christine C Snow[SUP] 1 [/SUP], Victoria Salinas[SUP] 4 [/SUP], R Sean Norman[SUP] 5 [/SUP], Heidi K Bojes[SUP] 4 [/SUP], Bryan W Brooks[SUP] 6 [/SUP]
Affiliations
Following the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in late 2019, the use of wastewater-based surveillance (WBS) has increased dramatically along with associated infrastructure globally. However, due to the global nature of its application, and various workflow adaptations (e.g., sample collection, water concentration, RNA extraction kits), numerous methods for back-calculation of gene copies per volume (gc/L) of sewage have also emerged. Many studies have demonstrated the comparability of processing methods (e.g., water concentration, RNA extraction); however, for equations used to calculate gene copies in a wastewater sample and subsequent influences on monitoring viral trends in a community and its association with epidemiological data, less is known. Due to limited information on how many formulas exist for the calculation of SARS-CoV-2 gene copies in wastewater, we initially quantified how many equations existed in the referred literature. We identified 23 unique equations, which were subsequently applied to an existing wastewater dataset. We observed a range of gene copies based on use of different equations, along with variability of AUC curve values, and results from correlation and regression analyses. Though many individual laboratories have independently converged on a similar formula for back-calculation of viral load in wastewater, and share similar relationships with epidemiological data, differential influences of various equations were observed for variation in PCR volumes, RNA extraction volumes, or PCR assay parameters. Such observations highlight challenges when performing comparisons among WBS studies when numerous methodologies and back-calculation methods exist. To facilitate reproducibility among studies, the different gc/L equations were packaged as an R Shiny app, which provides end users the ability to investigate variability within their datasets and support comparisons among studies.
Keywords: Gene copies per liter; SARS-CoV-2; Wastewater-based epidemiology; Wastewater-based surveillance.
. 2024 Jan 23:170345.
doi: 10.1016/j.scitotenv.2024.170345. Online ahead of print. Influences of 23 different equations used to calculate gene copies of SARS-CoV-2 during wastewater-based epidemiology
Mia G Ryon[SUP] 1 [/SUP], Laura M Langan[SUP] 2 [/SUP], Christopher Brennan[SUP] 3 [/SUP], Megan E O'Brien[SUP] 1 [/SUP], Fallon L Bain[SUP] 1 [/SUP], Aubree E Miller[SUP] 1 [/SUP], Christine C Snow[SUP] 1 [/SUP], Victoria Salinas[SUP] 4 [/SUP], R Sean Norman[SUP] 5 [/SUP], Heidi K Bojes[SUP] 4 [/SUP], Bryan W Brooks[SUP] 6 [/SUP]
Affiliations
- PMID: 38272099
- DOI: 10.1016/j.scitotenv.2024.170345
Following the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in late 2019, the use of wastewater-based surveillance (WBS) has increased dramatically along with associated infrastructure globally. However, due to the global nature of its application, and various workflow adaptations (e.g., sample collection, water concentration, RNA extraction kits), numerous methods for back-calculation of gene copies per volume (gc/L) of sewage have also emerged. Many studies have demonstrated the comparability of processing methods (e.g., water concentration, RNA extraction); however, for equations used to calculate gene copies in a wastewater sample and subsequent influences on monitoring viral trends in a community and its association with epidemiological data, less is known. Due to limited information on how many formulas exist for the calculation of SARS-CoV-2 gene copies in wastewater, we initially quantified how many equations existed in the referred literature. We identified 23 unique equations, which were subsequently applied to an existing wastewater dataset. We observed a range of gene copies based on use of different equations, along with variability of AUC curve values, and results from correlation and regression analyses. Though many individual laboratories have independently converged on a similar formula for back-calculation of viral load in wastewater, and share similar relationships with epidemiological data, differential influences of various equations were observed for variation in PCR volumes, RNA extraction volumes, or PCR assay parameters. Such observations highlight challenges when performing comparisons among WBS studies when numerous methodologies and back-calculation methods exist. To facilitate reproducibility among studies, the different gc/L equations were packaged as an R Shiny app, which provides end users the ability to investigate variability within their datasets and support comparisons among studies.
Keywords: Gene copies per liter; SARS-CoV-2; Wastewater-based epidemiology; Wastewater-based surveillance.