In a press released presented on July 7, 2020 the Academy of Medicine is concerned by the increasing traces of coronavirus in wastewater. The institution explains the importance of systematically monitoring this water in order to prevent the resurgence of the virus and – perhaps – anticipate a second contamination wave.
The latest sample collected by scientists revealed on July 22 a "low level" of traces of Covid-19 in waterwaste was found "in some local data tracking points in Paris" Eau de Paris and Obépine (Epidemiologic laboratory in Waterwaste) teams said.
"We noticed that samples that were negative came back up positive in some places" microbiology doctor and Eau de Paris R&D biology laboratory head Laurent Moulin explained to 20minutes. He says, "this very slight increase does not allow to draw conclusions as of the number of people infected".
On BFMTV, Laurent Moulin adds that "it was logical to find resurgence of the virus. (...) We are currently riding a dynamic that has a lower and slower increase than we have been able to see from the beginning of the epidemic, and we are on levels of concentration that are still the same as early March, at the beginning of the epidemic."
As of today, Eau de Paris laboratory analyzes about a hundred wastewater samples a week.
For the record, the Academy of Medicine writes that “the microbiological analysis of wastewater can play a strategic part in the prospective and regular surveillance of the circulation of the virus”. About 10% of people infected by Covid-19 show gastrointestinal disorders like diarrhea. Moreover, asymptomatic carriers of the virus and those potentially contagious can momentarily get rid of the virus in their feces (up to between 30 and 50%).
If coronavirus is “quickly inactivated in water” and cannot be transmitted that way, the analysis of wastewater will enable to notice increasing or decreasing traces of the virus in the population. Therefore, searchers could control evolutions of Covid-19 and foresee if new epidemic waves may break out.
Such surveillance is already set up in urban areas in many countries (France, the United-States, Spain, the Netherlands, Luxembourg, Italy). The Academy of Medicine says “qRT-PCR tests show the amount of nucleic acids is in correlation with the epidemic curve, preceding the outbreak of the wave, following its ascent and sharply decreasing with its regression. This direct temporal relation with the epidemic wave and especially prior to its outbreak, could make of this indicator a priceless tool to foreseen likely resurgences by testing the presence of the virus in hundreds of thousands of people”.