Antonella Amendola, an associate professor at the university, says they are crucial findings in Italy's initial phase of infection – before the first reported clinical case on February 21. Professor Elisabetta Tanzi says that neither the boy nor his family had traveled overseas in the weeks beforehand, "so it was a local case: he was infected in the region of Lombardy."
The researchers say that the "long-term, unrecognized spread of SARS-CoV-2 in northern Italy" would help explain the devastating impact and rapid course of the first wave of COVID-19 in Lombardy. Their study supports other evidence that the virus was in circulation earlier than previously thought, with traces of coronavirus found in the country's wastewater last year.
The National Institute of Health examined 40 samples from sewage plants in northern Italy from October last year to February this year. Results show COVID-19 was detected both in Milan and Turin on December 18, 2019.
A national surveillance system of the country's sewage system has since been established to help identify new outbreaks.
Scientists are encouraging further investigation into when and how Italy's coronavirus crisis began. "The invitation is this, to do more retrospective research because it is very important to retrace the route of transmission of the virus," says Amendola.