Scientists in Italy say they have found evidence of the virus that causes Covid-19 in sewage water dating from December, two months before the country's first reported infection and before China confirmed what are believed to be the first cases, posing questions about the timeline of the pandemic.
- Italy’s National Institute of Health (ISS) announced Thursday that sewage water samples drawn December 18 in the northern Italian cities of Milan and Turin contained genetic virus traces.
- That’s nearly two months before the first Covid-19 case was reported in Italy in mid-February, while China, where the pandemic is believed to have originated, has said it identified its first cases in late December.
- But the findings do not automatically imply that the deadly outbreak in Italy this year directly originated from these very first detected cases, and may have still come from a later introduction of the virus, ISS wastewater expert Giuseppina La Rosa told Reuters.
- A similar study in Spain detected Covid-19 traces in Barcelona waste water from mid-January, about 40 days before the first local case was found, and scientists in France found that a Frenchman was infected with the virus as early as late December, nearly a month before the country detected its first case.
- The earliest U.S. Covid-19 patient was diagnosed in mid-January in Washington, but two others in the same county tested positive for viral antibodies after experiencing Covid-19-like symptoms in December.
- However, some scientists say that’s not definitive proof the virus has been lingering in the U.S. since 2019, saying the two may have contracted an asymptomatic Covid-19 infection after being ill at the end of last year.
The sewage study findings appear to roughly match up with other research done into the origin and spread of the Covid-19 virus that has so far infected 8.5 million worldwide and killed upwards of 450,000. Researchers from London found evidence the virus began spreading between humans late last year and transmitted rapidly. It was disappointing news for many who hoped that the virus had actually been infecting people for months before that and that more of the population might have built up an immunity to it. “Everyone was hoping for that. I was too,” genetics researcher Francois Balloux, one of the study’s leaders, told CNN in May.