Viruses close to SARS-CoV-2 have been discovered in bats – Evenimentul Zilei

This could be a “major discovery” looking for the origins of Covid-19: researchers at the Pasteur Institute have identified SARS-CoV-2-like viruses in bats in northern Laos, capable of infecting humans.

The conclusions of these papers, which can be accessed on Wednesday, September 22 on the scientific platform “Research Square”, must be evaluated by experts in order to be published in a scientific journal. To better understand the evolution of SARS-CoV-2 and its origins, which have been the subject of intense speculation for months, researchers at the Pasteur Institute in Paris, the Pasteur Institute in Laos and the National University of Laos conducted at the end of 2020 and early 2021 a field mission in the north of the country with different species of bats that live in limestone caves.

“The initial idea was to try to identify the origin of this epidemic“, Explains for AFP Marc Eloit, the head of the laboratory responsible for the” discovery of pathogens “at the Pasteur Institute in Paris, whose teams analyzed the various samples collected. “For various reasons that are accumulating, it is suspected that certain insectivorous bats could be the reservoir of the virus.”

The place where bats live

The sampling took place in an area that is part of a huge karst relief, geological formations consisting mainly of limestone, which includes northern Vietnam and southern China. “Laos shares this common territory with southern China, full of cavities where bats live, hence the idea of ​​going there,” Marc Eloit continues. Because what is happening there is representative of this ecosystem.

Conclusions of the Pasteur Institute’s analysis: the virus sequences found in bats are almost identical to those of SARS-CoV-2 and the researchers were able to demonstrate their ability to allow viruses to enter human cells. However, the viruses studied did not have the “furin site” present in SARS-CoV-2, a function that activates the so-called Spike protein, allowing the virus to penetrate better into human cells, and whose existence conditions the pathogenic power of the virus.

Several hypotheses could explain this missing link, says Marc Eloit. “It simply came to our notice then virus is pathogenic it first circulated in humans before undergoing mutations “, he underlines. “Or a virus very close to the ones identified has this furin site, but we haven’t found it yet.” Another question: “How did the bat virus found in the caves reach Wuhan” in China, known as the starting point of the pandemic, 2000 km away? There is no answer at the moment.

There are SARS-CoV-2-like viruses

However, this study “represents a major step forward in identifying the origin of SARS-CoV-2,” says Marc Eloit. The main conclusion would be that there are viruses very similar to SARS-CoV-2 in bats, capable of infecting people without an intermediate animal, such as pangolin. At the end of August, WHO experts, the authors of a report on the origin of Covid, warned that research was “deadlocked” on the subject.

They were part of a team of 17 international experts appointed by the WHO and 17 Chinese experts, whose report was published on March 29, following an investigation in January in Wuhan. Without providing a clear answer, this report listed four more or less likely scenarios. The most likely consideration was the transmission of the virus to humans through an animal infected with a bat.

Then came the hypotheses of a direct transmission without an intermediate animal, of transmission through food, especially through frozen meat, and, finally, of an accidental leak from the laboratory, which was considered “extremely unlikely” anyway. Since then, “no date” to support “the hypothesis of a laboratory leak has neither been published nor transmitted to the WHO,” experts said.

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