ROME: The coronavirus was already present in two large cities in northern Italy in December, over two months before the first case was detected, a national health institute study of wastewater has found.
Researchers discovered genetic traces of Sars-Cov-2, the virus that causes Covid-19, in samples of wastewater collected in Milan and Turin at the end of last year, and Bologna in January, the ISS institute said in a statement.
Italy’s first known native case was discovered mid-February.
The results “help to understand the start of the circulation of the virus in Italy,” the ISS said.
They “confirm the by-now consolidated international evidence” as to the strategic function of sewer samples as an early detection tool, it added.
Italy was the first European country to be hit by the virus and the first in the world to impose a nationwide lockdown. The first known case, other than a couple of visiting Chinese tourists, was a patient in the town of Codogno in the Lombardy region.
Italy has recorded over 34,500 deaths.
ISS water quality expert Giuseppina La Rosa and her team examined 40 wastewater samples from October 2019 to February 2020.
Samples from October and November 2019 were negative, showing the virus had yet to arrive, La Rosa said.
Given the large number of coronavirus cases that have little or no symptoms, wastewater testing could signal the presence of the virus even before the first cases are clinically confirmed in areas untouched by the epidemic or where it has ebbed.
The ISS is launching a pilot study of sewage samples at priority sites identified in tourist resorts in July, and expected to set up a nationwide surveillance network of wastewater by the autumn.
The first trial results of a coronavirus vaccine being developed by CureVac are expected in two months, German news website Focus Online reported.
CureVac, an unlisted German company, this week said first meaningful results could be available in September or October and, under favourable conditions, it could be approved by the middle of next year.