SARS-CoV-2 has recently been detected in feces, which indicates that wastewater may be used to monitor viral prevalence in the community. Here we use RT-qPCR to monitor wastewater for SARS-CoV-2 RNA over a 74-day time course. We show that changes in SARS-CoV-2 RNA concentrations follow symptom onset gathered by retrospective interview of patients but precedes clinical test results. Additionally, we determine a near complete (98.5%) SARS-CoV-2 genome sequence from the wastewater and use phylogenetic analysis to infer viral ancestry. Collectively, this work demonstrates how wastewater can be used as a proxy to monitor viral prevalence in the community and how genome sequencing can be used for genotyping viral strains circulating in a community.
Collectively, the results presented here demonstrate that wastewater monitoring for SARS-CoV-2 RNA by RT-qPCR provides a real-time measure of viral prevalence in the community (Fig 1). Clinical testing for COVID-19 typically occurs 3-9 days after Journal Pre-proof 8 symptoms onset and might vary depending on availability of tests, care-seeking behavior, workloads in testing facilities and current testing strategy In our study, wastewater surveillance for SARS-CoV-2 foreshadowed new case reports by 2-4 days. The statistics of lab-confirmed COVID-19 cases not only lag behind viral spread, but also underestimates the true scale of the current pandemic. Recent analysis of outpatient surveillance data estimates that only 32% of SARS-CoV-2 infected individuals in the US sought medical care. These challenges are overcome with wastewater testing, which captures input from all individuals in the local community and thus has the potential for estimating the true prevalence of COVID-19 using computational models that account for the median viral load in stool, virus degradation rates, travel time to the treatment facility and water use per-capita.
Furthermore, wastewater may capture mild and asymptomatic infections that might be used to alert Public Health officials about emerging undetected transmission events. Monitoring wastewater for SARS-CoV-2 provides a useful epidemiological metric that could help track the outbreak and inform policy. The study presented here complements the rapidly emerging body of work by providing an important link between wastewater surveillance, COVID-19 epidemiology and tracing SARS-CoV-2 spread patterns with genome sequencing.
Reference & Source information: https://www.cell.com/
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