Benchmarking virus concentration methods for quantification of SARS-CoV-2 in raw wastewater.

Affiliation

Jafferali MH(1), Khatami K(2), Atasoy M(2), Birgersson M(3), Williams C(1), Cetecioglu Z(4).
Author information:
(1)Department of Protein Science, KTH Royal Institute of Technology, Science for Life Laboratory, Solna, Sweden.
(2)Department of Chemical Engineering, KTH Royal Institute of Technology, SE-100 44, Sweden.
(3)Department of Protein Science, KTH Royal Institute of Technology, Science for Life Laboratory, Solna, Sweden; Department of Biosciences and Nutrition, Karolinska Institute, Huddinge, Sweden.
(4)Department of Chemical Engineering, KTH Royal Institute of Technology, SE-100 44, Sweden. Electronic address: [Email]

Abstract

Wastewater-based epidemiology offers a cost-effective alternative to testing large populations for SARS-CoV-2 virus, and may potentially be used as an early warning system for SARS-CoV-2 pandemic spread. However, viruses are highly diluted in wastewater, and a validated method for their concentration and further processing, and suitable reference viruses, are the main needs to be established for reliable SARS-CoV-2 municipal wastewater detection. For this purpose, we collected wastewater from two European cities during the Covid-19 pandemic and evaluated the sensitivity of RT-qPCR detection of viral RNA after four concentration methods (two variants of ultrafiltration-based method and two adsorption and extraction-based methods). Further, we evaluated one external (bovine corona virus) and one internal (pepper mild mottle virus) reference virus. We found a consistently higher recovery of spiked virus using the modified ultrafiltration-based method. This method also had a significantly higher efficiency (p-value <0.01) for wastewater SARS-CoV-2 detection. The ultracentrifugation method was the only method that detected SARS-CoV-2 in the wastewater of both cities. The pepper mild mottle virus was found to function as a potentially suitable internal reference standard.