Xinhua
A couple walks on a street during the COVID-19 pandemic in Barcelona, Spain, on June 19, 2020.
Researchers from the University of Barcelona, one of the most prestigious universities in Spain, detected the presence of the new coronavirus in the wastewater samples collected here on March 12, 2019, the university said in a statement on Friday.
“These results, submitted to a high-impact journal and published in the medRxiv archive, suggest that the infection was present before any case of COVID-19 was known anywhere in the world,” the statement said.
The study was led by researchers from the Enteric Virus Laboratory at the University of Barcelona in collaboration with the public-private company Aigues de Barcelona, which is responsible for managing the water cycle in the Barcelona metropolitan area, he said.
The study “has not been peer-reviewed,” the researchers said in medRxiv, an online archive that distributes unpublished health science documents.
Xinhua
Workers paint a line on the street to adapt pedestrian mobility and ensure social distancing in Barcelona, Spain, on May 19, 2020.
Previous presence in Spain
“Although COVID-19 is a respiratory disease, the researchers proved that there are large amounts of the coronavirus genome in the droppings that reach the wastewater. This situation made wastewater-based epidemiology a potential tool for early detection of virus circulation among the population, “the statement said.
Since April 13 of this year, the researchers analyzed weekly the samples obtained in the two main water treatment plants in Barcelona.
“The levels of the SARS-CoV-2 (or new coronavirus) genome coincided with the evolution of COVID-19 cases in the population”, Albert Bosch, professor at the Faculty of Biology of the University of Barcelona and coordinator of the study he said in the statement.
During systematic sampling, the researchers analyzed frozen samples from previous months, which revealed the growing appearance of the new coronavirus genome between early January and early March this year, he said.
The findings brought the date of the arrival of the coronavirus to Spain even earlier: the presence of the virus was detected on January 15, 41 days before the official announcement of the first case of COVID-19 on February 25, according to the statement.
According to the researchers, these results show the validity of monitoring wastewater to anticipate cases.
“People infected with COVID-19 could have been mistakenly diagnosed with influenza in primary care, contributing to community transmission before public health authorities took action,” said Bosch, who is also president of the Spanish Society of Virology.
Xinhua
An operator cleans and disinfects garbage containers in the midst of the COVID-19 outbreak in Barcelona, Spain, on May 15, 2020.
Shocking results
These results encouraged researchers to analyze frozen samples taken between January 2018 and December 2019, which led to “shocking results from the presence of the SARS-CoV-2 genome in March 2019,” the statement said.
“All samples were negative with respect to the presence of the SARS-CoV-2 genome, except those taken on March 12, 2019, in which the SARS-CoV-2 levels were low but positive, using two different objectives “Bosch said.
“Barcelona receives many visitors for tourism and professional reasons, and a similar situation may have occurred in other parts of the world, also because most cases of COVID-19 show flu-like symptoms. Those cases could have been disguised as an undiagnosed flu, “he said in the statement.
To date, the new coronavirus has been contracted by nearly ten million people and killed half a million worldwide since the central Chinese city of Wuhan first reported the outbreak in late 2019.
