Covid: pangolin, bat… two years after the start of the pandemic, what do we know about the origin of the virus?

Two years ago, the world discovered with amazement the Covid-19 pandemic. Today, do we know a little more about the origins of this virus? We take stock.

The mystery persists. After two years of pandemic, one question remains open: what is the origin of the Sars-Cov2 coronavirus? Two hypotheses remain on the table:

  • The first is that of the virus escaping from a Chinese laboratory.
  • Second hypothesis: transmission from animals to humans. And that’s where our friend the pangolin comes in. Which is more plausible?

Blame the bats?

The hypothesis of transmission from animals to humans is becoming clearer. Researchers from the Institut Pasteur have discovered three coronaviruses very close to the one we know. One of the viruses spotted by the researchers is the most similar ever analyzed so far. These viruses discovered thanks to a study on 645 bats in a cave in Laos are capable of infecting human cells, like Sars-Cov2.

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Origin of Covid: similar viruses discovered in bats, capable of infecting humans

The results of this study, already revealed in advance in September 2021 on the scientific platform “Research Square”were confirmed and officially published on Wednesday February 16 in the scientific journal “Nature”.

“Three viruses show genomic similarities with Sars-Cov-2, in particular in a key domain of the Spike protein, which allows the virus to bind to host cells”, write the scientists from the Institut Pasteur.

“Researchers have demonstrated a similar affinity of these three bat coronaviruses and the Sars-Cov-2 virus for a human receptor, as well as an ability to enter human cells,” they continue, indicating that the one of these three strains is even “capable of multiplying in human cells“.

“The existence of these viruses discovered in the bat animal reservoir supports the hypothesis that Sars-Cov-2 could have originated from bats living in the reliefs […] shared by Laos, Vietnam and China”, explains the virologist Marc Eloit, relayed by South West, head of the “Discovery of pathogens” laboratory at the Institut Pasteur and who led the study. “Our results tend to prove that other related viruses could pose a risk to human health,” he adds.

How did the virus get to Wuhan?

The Institut Pasteur specifies that the viruses studied in these bats and in particular those from Laos “do not have a furin cleavage site”, which allows Covid-19 to penetrate the respiratory cells of humans and to be pathogenic.

However, this thesis does not explain how Covid-19 could have appeared in Wuhan in China when the bats studied come from southern China and northern Laos and Vietnam. “The virus did not appear where bats live. (…) This raises the question of how it was transported”, pointed out Marc Eloit, head of the “Discovery of pathogens” laboratory at the Institut Pasteur, to our colleagues from The Express.

China does not want to know anything

“China, which cannot bear to be implicated in this pandemic, stubbornly refuses the communication of the files, perhaps even that it destroyed them. There is a will to hide. As long as this is the case, we will remain at the stage of hypotheses”, explains Didier Sicard, professor of medicine, former president of the National Consultative Ethics Committee (CCNE) with our colleagues from the Parisian.

“Given what is happening in China, we should not have too many illusions”, declares in this sense the professor of infectiology Éric Caumes. “Politically, it is sensitive. It is possible that we will never find”, he concludes.

The exonerated pangolin?

It’s not the pangolin, definitely “innocent”. Among the serious leads are small rodents called raccoon dogs, massively bred for their fur. For Sras, it was the civet. The Seas, the dromedary”, according to Didier Sicard interviewed by The Parisian.

A thesis supported by Marc Eloit, head of the “Discovery of pathogens” laboratory at the Institut Pasteur: “The pangolin may have appeared as a crucible, because we found in this animal coronaviruses with an RBD closest to Sars-Cov2 “With the viruses that we have found, the Pangolin no longer appears to be a possible intermediary. But more likely a collateral victim, infected by bats”, explains Marc Eloit to the express.

If we don’t have a better understanding of the pathways from animals to humans, history will repeat itself. Other coronaviruses are ready to take over…

For Didier Sicard, it would have been necessary to take immediate samples from the bats. It warns about the probable arrival of new coronaviruses in the future if we do not have more data.

What about the theory of a virus made in the Wuhan lab?

“Impossible. It’s a mystery novel hypothesis. Who wants to risk a virus war when the risk of falling on the sender is so great?” argues the professor of medicine Didier Sicard to the Parisian.

If we are familiar with the coronavirus, the latter still presents many mysteries…

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