Spanish virologists have found traces of the novel coronavirus in a sample of Barcelona waste water collected in March 2019, nine months before the COVID-19 disease was identified in China, the University of Barcelona said on Friday.
The discovery of virus genome presence so early in Spain, if confirmed, would imply the disease may have appeared much earlier than the scientific community thought.
The University of Barcelona team, who had been testing waste water since mid-April this year to identify potential new outbreaks, decided to also run tests on older samples.
They first found the virus was present in Barcelona on Jan. 15, 2020, 41 days before the first case was officially reported there.
Then they ran tests on samples taken between January 2018 and December 2019 and found the presence of the virus genome in one of them, collected on March 12, 2019.
“The levels of SARS-CoV-2 were low but were positive,” research leader Albert Bosch was quoted as saying by the university.
In mid-June, Italian scientists said that they had found traces of coronavirus in sewage samples there taken in mid-December of last year in Milan and Turin.
“This research may help us understand the beginning of virus circulation in Italy,” Giuseppina La Rosa, an expert in environmental wastewater at the Italian National Institute of Health who co-led the research, said in a statement detailing the findings.
Small studies conducted by scientific teams in the Netherlands, France, Australia and elsewhere have found signs that the virus that causes COVID-19 can be detected in sewage, and many countries are beginning to use wastewater sampling to track the spread of the disease.
Sewage from Ottawa and Gatineau is now being regularly sampled for traces of coronavirus.
Scientists Global News has spoken to point to sewage tests as a potential early-warning system which could alert communities to a second wave of the virus, or fresh outbreaks at a more local level, like in schools or long-term care facilities.
Was the virus lurking in Canadian communities long before we had heard of it?
Sewage samples exist that may be able to answer the question. Statistics Canada has been taking monthly samples of sewage from Montreal, Halifax, Toronto, Edmonton and Vancouver since March of 2018, originally to test for illicit drugs, and those samples have been reserved.
La Rosa said the detection of traces of the virus before the end of 2019 was consistent with evidence emerging in other countries that COVID-19 may have been circulating before China reported the first cases of a new disease on Dec. 31.
A study in May by French scientists found that a man was infected with COVID-19 as early as December 27, nearly a month before France confirmed its first cases.
La Rosa said the presence of the virus in the Italian waste samples did not “automatically imply that the main transmission chains that led to the development of the epidemic in our country originated from these very first cases.”
Samples positive for traces of the virus that causes COVID-19 were also found in sewage from Bologna, Milan and Turin in January and February 2020. Samples taken in October and November 2019 tested negative.
The Spanish research has been submitted for a peer review.
Dr Joan Ramon Villalbi of the Spanish Society for Public Health and Sanitary Administration told Reuters it was still early to draw definitive conclusions.
“When it’s just one result, you always want more data, more studies, more samples to confirm it and rule out a laboratory error or a methodological problem,” he said.
With files from Global News