Define the biological and biophysical properties of SARS-CoV-2 genetic material in wastewater

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This article was originally published here

Sci Total Approx. 2021 Oct 4: 150786. doi: 10.1016 / j.scitotenv.2021.150786. Online ahead of print.

ABSTRACT

SARS-CoV-2 genetic material has been detected in raw sewage around the world throughout the COVID-19 pandemic and has served as a useful tool to monitor community levels of SARS-CoV infections -2. The genetic material of SARS-CoV-2 is highly detectable in a patient’s stool and household sewage for several days before and after a positive COVID-19 qPCR test from throat or sputum samples. Here, we characterize the genetic material collected from raw wastewater samples and determine the efficiency of recovery during a concentration process. We find that pasteurization of raw wastewater samples did not reduce the SARS-CoV-2 signal if RNA is extracted immediately after pasteurization. In contrast, we find that the signal decreased by about half when RNA was extracted 24-36 h after pasteurization and by about 90% when freeze-thaw before concentration. As a matrix control we use a modified enveloped RNA virus. Surprisingly, after concentration, the recovery of the SARS-CoV-2 signal is consistently greater than the recovery of the control virus, which leads us to question the nature of the SARS-CoV-2 genetic material detected in wastewater. We do not see any significant difference in the signal after different temperature changes over 24 hours; however, treatment with detergent decreases the signal by about 100 times. In addition, the density of the samples is comparable to that of enveloped retrovirus particles, but, interestingly, when raw sewage samples were used to inoculate cells, no cytopathic effect was observed, indicating that the Wastewater samples do not contain infectious SARS-CoV-2. Together, this suggests that the wastewater contains enveloped particles that are fully intact.

PMID:34619200 | DO I:10.1016 / j.scitotenv.2021.150786


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