A woman puts on her face mask and prepares to enter the Louvre Museum in Paris, France, July 6, 2020. (Xinhua/Gao Jing)
Analysis of the latest sewage water samples taken in the Great Paris region suggested a slight resumption of the novel coronavirus in the past weeks but it is too early to speak of an epidemic rebound, French media reported on Wednesday.
Six of the 12 samples analyzed between June 22 and 25 found a very minimal presence of the coronavirus and additional tests carried out the following week confirmed these results, said national daily Le Monde.
Additional elements are needed to understand the phenomenon, it said, warning that "recent resumption of activities has been accompanied by a certain relaxation in terms of compliance with barrier gestures, which raises fears of a resurgence of the epidemic."
Sewage water reflects what is excreted by the public. Paris has been monitoring its waste water since the start of the pandemic to assess the circulation of coronavirus among the population.
From samples taken between March 5 and April 23, researchers have indeed found a correlation between the level of virus in waste water and the number of infection cases.
In mid-April when a tiny amount of the virus was found at four of the 27 sampling points, the Paris City Hall immediately asked people to stop using non-potable water as a "precautionary measure."
In mid-May when the epidemic was largely contained after two months of confinement, traces of the coronavirus were no longer found in the waste water samples analyzed.
France's National Academy of Medicine said on Tuesday that the microbiological analysis of waste water can play a strategic role in prospective and regular surveillance of the circulation of the virus.
It recommended to make this surveillance systematic and rigorous, extend it to other viruses and constitute a bank of samples allowing retrospective analysis.
On June 26, researchers at the University of Barcelona, one of Spain's most prestigious universities, said they had detected the presence of the novel coronavirus in waste water samples collected in Barcelona on March 12 of 2019. That was nine months before China's central city of Wuhan first reported the coronavirus outbreak at the end of 2019.
Scientists in Italy also found traces of the new coronavirus in waste water collected from Milan and Turin in December 2019.
