Traces of coronavirus have been detected in wastewater collected in Barcelona, Spain from March 2019, nearly a year earlier than when the first official case was recorded in Europe, research published by the University of Barcelona revealed Friday.
The timeline of COVID-19, which was originally to have thought to have begun spreading in December 2019 in Wuhan, China, has been challenged by a wave of recent scientific studies suggesting that the virus began spreading much earlier.
“Barcelona receives many visitors for both tourist and professional reasons and it is possible for a similar situation to have taken place in other parts of the world, and since most of the COVID-19 cases show a similar symptomatology to the flu, those cases could have been disguised as an undiagnosed flu,” Albert Bosch, a biology professor at the University of Barcelona and researcher in the study said in a statement on the university’s website.
The researchers examined wastewater from two large treatment facilities in Barcelona as part of a study into whether using wastewater surveillance could help anticipate the spread of pathogens much earlier.
The coronavirus was also detected in water from January 15, over 40 days earlier than the announcement of the first Spanish case of coronavirus on February 25.
Considering the high number of carriers of coronavirus that show very mild symptoms, or are entirely asymptomatic, using wastewater to detect cases could be of use, the researchers said.
“Those infected with COVID-19 could have been diagnosed with flu in primary care by mistake, contributing to the community transmission before the public health took measures,” Bosch said.
“In the specific case of Barcelona, having detected the SARS-CoV-2 spread a month before could have improved the response to the pandemic,” he added.
The study has been submitted for peer review. If approved, it may add to other evidence that the coronavirus spread for much longer and much earlier than the scientific community previously suspected.
Earlier this month, scientists in Italy found traces of COVID-19 in wastewater collected from northern Italy in December 2019. Meanwhile a study in May by French scientists found a man infected with the coronavirus as early as December 27, nearly a month before France confirmed its first official case.