Time-evolution of SARS-CoV-2 in wastewater during the first pandemic wave of COVID-19 in the metropolitan area of Barcelona

Two large wastewater treatment plants (WWTP), covering around 2.7 M inhabitants, which represents around 85% of the metropolitan area of Barcelona, were sampled before, during and after the implementation of a complete lockdown. Five one-step RT-qPCR assays, targeting the polymerase (IP2 and IP4), t...

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Detalles Bibliográficos
Autores: Chavarria Miró, Gemma, Anfruns-Estrada, Eduard, Martínez-Velázquez, Adán, Vázquez Portero, Mario, Guix Arnau, Susana, Paraira, Miquel, Galofré, Belén, Sánchez, Gloria, Pintó Solé, Rosa María, Bosch, Albert
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2021
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/175917
Acceso en línea:https://hdl.handle.net/2445/175917
Access Level:acceso abierto
Palabra clave:SARS-CoV-2
COVID-19
Aigües residuals
Barcelona (Catalunya : Àrea metropolitana)
Sewage
Barcelona (Catalonia : Metropolitan area)
Descripción
Sumario:Two large wastewater treatment plants (WWTP), covering around 2.7 M inhabitants, which represents around 85% of the metropolitan area of Barcelona, were sampled before, during and after the implementation of a complete lockdown. Five one-step RT-qPCR assays, targeting the polymerase (IP2 and IP4), the envelope E and the nucleoprotein (N1 and N2) genome regions, were employed for SARS-CoV-2 RNA detection in 24-h composite wastewater samples concentrated by polyethylene glycol (PEG) precipitation. SARS-CoV-2 was detected in a sewage sample collected 41 days ahead of the declaration of the first COVID-19 case. The evolution of SARS-CoV-2 genome copies in wastewater evidenced the validity of water-based epidemiology to anticipate COVID-19 outbreaks, to evaluate the impact of control measures and even to estimate the burden of shedders, including presymptomatic, asymptomatic, symptomatic and undiagnosed cases. For this latter objective, a model was applied for the estimation of the total number of shedders, evidencing a high proportion of asymptomatic infected individuals. In this way, an infection prevalence of 2.0-6.5% was figured. On the other hand, a proportion of around 0.12% and 0.09% of the total population was determined to be required for positive detection in the two WWTPs. At the end of the lockdown, SARS-CoV-2 RNA apparently disappeared in the WWTPs but could still be detected in grab samples from four urban sewers. Sewer monitoring allowed for location of specific hot spots of COVID-19, enabling the rapid adoption of appropriate mitigation measures.