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. 2022 Feb 1;806(Pt 4):150816.
doi: 10.1016/j.scitotenv.2021.150816. Epub 2021 Oct 8.

SARS-CoV-2 RNA in urban wastewater samples to monitor the COVID-19 pandemic in Lombardy, Italy (March-June 2020)

Sara Castiglioni  1 , Silvia Schiarea  2 , Laura Pellegrinelli  3 , Valeria Primache  3 , Cristina Galli  3 , Laura Bubba  3 , Federica Mancinelli  2 , Marilisa Marinelli  4 , Danilo Cereda  5 , Emanuela Ammoni  5 , Elena Pariani  3 , Ettore Zuccato  2 , Sandro Binda  3
Affiliations

SARS-CoV-2 RNA in urban wastewater samples to monitor the COVID-19 pandemic in Lombardy, Italy (March-June 2020)

Sara Castiglioni et al. Sci Total Environ. .

Abstract

Wastewater-based viral surveillance was proposed as a promising approach to monitor the circulation of SARS-CoV-2 in the general population. The aim of this study was to develop an analytical method to detect SARS-CoV-2 RNA in urban wastewater, and apply it to follow the trends of epidemic in the framework of a surveillance network in the Lombardy region (Northern Italy). This area was the first hotspot of COVID-19 in Europe and was severely affected. Composite 24 h samples were collected weekly in eight cities from end-March to mid-June 2020 (first peak of the pandemic). The method developed and optimized, involved virus concentration using PEG centrifugation, and one-step real-time RT-PCR for analysis. SARS-CoV-2 RNA was identified in 65 (61%) out of 107 samples, and the viral concentrations (up to 2.1 E + 05 copies/L) were highest in March-April. By mid-June, wastewater samples tested negative in all the cities corresponding to the very low number of cases recorded in the same period. Viral loads were calculated considering the wastewater daily flow rate and the population served by each wastewater treatment plant, and were used for inter- city comparison. The highest viral loads were found in Brembate, Ranica and Lodi corresponding to the hotspots of the first peak of pandemic. The pattern of decrease of SARS-CoV-2 in wastewater was closely comparable to the decline of active COVID-19 cases in the population, reflecting the effect of lock-down. This study tested wastewater surveillance of SARS-CoV-2 to follow the pandemic trends in one of most affected areas worldwide, demonstrating that it can integrate ongoing virological surveillance of COVID-19, providing information from both symptomatic and asymptomatic individuals, and monitoring the effect of health interventions.

Keywords: Active cases; Environmental surveillance; SARS-CoV-2; Urban wastewater; Viral loads.

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Conflict of interest statement

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Unlabelled Image
Graphical abstract
Fig. 1
Fig. 1
Cities and wastewater treatment plants (WWTPs) investigated in Lombardy, Italy.
Fig. 2
Fig. 2
SARS-CoV-2 RNA viral loads in wastewater samples and active cases in northwestern Lombardy (Bergamo and Brescia provinces).
Fig. 3
Fig. 3
SARS-CoV-2 RNA viral loads in wastewater samples and active cases in south Lombardy (Lodi, Crema and Cremona) and in Milan.
See this image and copyright information in PMC

References

    1. Aarestrup F.M., Woolhouse M.E.J. Using sewage for surveillance of antimicrobial resistance. Science. 2020;367:630–632. doi: 10.1126/science.aba3432. - DOI - PubMed
    1. Agrawal S., Orschler L., Lackner S. Long-term monitoring of SARS-CoV-2 RNA in wastewater of the Frankfurt metropolitan area in southern Germany. Sci. Rep. 2021;11 doi: 10.1038/s41598-021-84914-2. - DOI - PMC - PubMed
    1. Ahmed W., Angel N., Edson J., Bibby K., Bivins A., O’Brien J.W., Choi P.M., Kitajima M., Simpson S.L., Li J., Tscharke B., Verhagen R., Smith W.J.M., Zaugg J., Dierens L., Hugenholtz P., Thomas K.V., Mueller J.F. First confirmed detection of SARS-CoV-2 in untreated wastewater in Australia: a proof of concept for the wastewater surveillance of COVID-19 in the community. Sci. Total Environ. 2020;728 doi: 10.1016/j.scitotenv.2020.138764. - DOI - PMC - PubMed
    1. Ahmed W., Bertsch P.M., Bibby K., Haramoto E., Hewitt J., Huygens F., Gyawali P., Korajkic A., Riddell S., Sherchan S.P., Simpson S.L., Sirikanchana K., Symonds E.M., Verhagen R., Vasan S.S., Kitajima M., Bivins A. Decay of SARS-CoV-2 and surrogate murine hepatitis virus RNA in untreated wastewater to inform application in wastewater-based epidemiology. Environ. Res. 2020;191 doi: 10.1016/j.envres.2020.110092. - DOI - PMC - PubMed
    1. Ahmed W., Bivins A., Bertsch P.M., Bibby K., Choi P.M., Farkas K., Gyawali P., Hamilton K.A., Haramoto E., Kitajima M., Simpson S.L., Tandukar S., Thomas K.V., Mueller J.F. Surveillance of SARS-CoV-2 RNA in wastewater: methods optimization and quality control are crucial for generating reliable public health information. Curr. Opin. Environ. Sci. Health. 2020;17:82–93. doi: 10.1016/j.coesh.2020.09.003. - DOI - PMC - PubMed