No abstract

The route of SARS-CoV-2 from faeces to wastewater treatment plants is analysed.• Viral load in the faeces of positive people for SARS-CoV-2 is 5•10 3 -10 7.6 copies/mL. • Viral load decreases from 2 copies/ 100 mL to 3•10 3 copies/mL when entering a WWTP. • For WBE high uncertainty of viral loads remains, and further research is needed. • CoVs inactivation in WWTPs is enhanced by tertiary treatments and disinfection.

Detection of SARS-CoV-2 in wastewater in Italy is described for the first time.• Use of the PEG/dextran concentration method for SARS-CoV-2 is reported. • A novel nested PCR assay specific for SARS-CoV-2 was designed. • Wastewater-based epidemiology can be applied for COVID-19 surveillance.

No abstract

Several studies have demonstrated the advantages of environmental surveillance through the monitoring of sewer systems for the assessment of viruses circulating in a given community (wastewater-based epidemiology, WBE). During the COVID-19 public health emergency, many reports have described the presence of SARS-CoV-2 RNA in stools from COVID-19 patients, and a few studies reported the occurrence of SARS-CoV-2 in wastewaters worldwide. Italy is among the world's worst-affected countries in the COVID-19 pandemic, but so far there are no studies assessing the presence of SARS-CoV-2 in Italian wastewaters. To this aim, twelve influent sewage samples, collected between February and April 2020 from Wastewater Treatment Plants in Milan and Rome, were tested adapting, for concentration, the standard WHO procedure for Poliovirus surveillance. Molecular analysis was undertaken with three nested protocols, including a newly designed SARS-CoV-2 specific primer set. SARS-CoV-2 RNA detection occurred in volumes of 250 mL of wastewaters collected in both areas at high (Milan) and low (Rome) epidemic circulation, according to clinical data. Overall, 6 out of 12 samples were positive. One of the positive results was obtained in a Milan wastewater sample collected a few days after the first notified Italian case of autochthonous SARS-CoV-2. The study shows that WBE has the potential to be applied to SARS-CoV-2 as a sensitive tool to study spatial and temporal trends of virus circulation in the population.