Toward Reliable Detection and Quantification of SARS-CoV-2 in Wastewater and Environmental Water

In the context of wastewater-based epidemiology (WBE) targeting SARS-CoV-2, it is necessary to reliably detect and quantify SARS-CoV-2 gene in wastewater even when its concentration is low. Several attempts have been made to increase concentration factor before RT-qPCR process to enable the successful quantification of SARS-CoV-2 gene. Wastewater contains impurities that adversely affect virus detection processes, i.e., concentration, RNA extraction, and RT-qPCR processes. Due to the impurities, SARS-CoV-2 quantification can be unsuccessful even though the concentration factor is sufficiently high. In this chapter, by reviewing studies on SARS-CoV-2 and enteric viruses in water, ways to increase the concentration factor, their potential unfavorable outcomes, and countermeasures for the outcomes are discussed. As countermeasures, methods to maintain the detection efficiency high and methods to evaluate the detection efficiency through process control are widely adopted. There are many options for both methods. For reliable detection and quantification of SARS-CoV-2 in wastewater, it is necessary to select a series of detection methods after careful consideration on their effectiveness and limitations.