Potential Use of Untreated Wastewater for Assessing COVID-19 Trends in Southern Italy.

Osvalda De Giglio,Giuseppina Caggiano,Pasquale Stefanizzi,Francesca Apollonio,Giusy Diella,Francesco Triggiano,Luca Lucentini,Giovanna Barbuti,Angelo Marzella,Silvia Brigida,Chrysovalentinos Pousis,Fabrizio Fasano,Elisabetta Suffredini,Carla Calia,Maria Teresa Montagna,Marco Lopuzzo,Giuseppina La Rosa

doi:10.3390/ijerph181910278

Abstract

As a complement to clinical disease surveillance, the monitoring of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in wastewater can be used as an early warning system for impending epidemics. This study investigated the dynamics of SARS-CoV-2 in untreated wastewater with respect to the trend of coronavirus disease 2019 (COVID-19) prevalence in Southern Italy. A total of 210 wastewater samples were collected between May and November 2020 from 15 Apulian wastewater treatment plants (WWTP). The samples were concentrated in accordance with the standard of World Health Organization (WHO, Geneva, Switzerland) procedure for Poliovirus sewage surveillance, and molecular analysis was undertaken with real-time reverse-transcription quantitative PCR (RT-(q) PCR). Viral ribonucleic acid (RNA) was found in 12.4% (26/210) of the samples. The virus concentration in the positive samples ranged from 8.8 × 102 to 6.5 × 104 genome copies/L. The receiver operating characteristic (ROC) curve modeling showed that at least 11 cases/100,000 inhabitants would occur after a wastewater sample was found to be positive for SARS-CoV-2 (sensitivity = 80%, specificity = 80.9%). To our knowledge, this is the first study in Italy that has applied wastewater-based epidemiology to predict COVID-19 prevalence. Further studies regarding methods that include all variables (meteorological phenomena, characteristics of the WWTP, etc.) affecting this type of wastewater surveillance data would be useful to improve data interpretation.

Highlights

Licensee MDPI, Basel, Switzerland.Several studies have investigated the presence of Severe Acute RespiratorySyndrome Coronavirus 2 (SARS-CoV-2) in wastewater [1,2,3,4,5] in the world
SARS-CoV-2 ribonucleic acid (RNA) was present in 12.4% (26/210) of the samples
The analysis showed a cut off value for which at least 11 cases/100,000 inhabitants would occur after a wastewater sample was found to be positive for SARSCoV-2

Summary

Introduction

Several studies have investigated the presence of Severe Acute Respiratory. Syndrome Coronavirus 2 (SARS-CoV-2) in wastewater [1,2,3,4,5] in the world. Viral shedding in stool can occur in 50% of symptomatic, asymptomatic, pre- and post-symptomatic patients with coronavirus disease 2019 (COVID-19). The shedding duration at a load of 102 to 108 ribonucleic acid (RNA) copies/g varies among patients, with an average of. 14–21 days [6,7,8,9,10,11].

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