Two studies have concluded that the pandemic started well in the Wuhan market

The researchers established that the first 155 known cases were concentrated in the city market and that the virus was mostly in the area where the animals were.

Two studies published Tuesday in the prestigious journal Science concluding that the Covid-19 pandemic began in the market in the city of Wuhan, China, thus pointing to a likely source of the virus.

The first study is a geographic analysis that shows that the first cases found in December 2019 are concentrated around the market. The second is a genomic analysis of the virus from the first cases, which shows that the virus is not very likely to have spread to most people before November 2019.

The debate has raged since the beginning of the pandemic between experts, who are still searching almost three years later to clarify the mystery of the origin of the virus. One of the authors of these studies himself, Michael Worobey, a virologist at the University of Arizona, signed a letter in 2021 calling for serious consideration of the hypothesis of a leak from a laboratory in Wuhan .

But the data has since been reviewedmade me change, to the point that now I also think that it is absolutely unbelievable that the virus was introduced in any other way than through the animal trade in the Wuhan market“, he said in a press conference.

The first cases were concentrated around the market

Kristian Andersen, of the Scripps Research Institute and co-author of these studies, said: “Have we disproved the lab leak theory? No. Can we do it one day? No. But I think it’s important to understand that there are possible scenarios, and probabilities. And that possible doesn’t mean equally likely.»

The first study examined the places of residence of the first 155 cases identified in December 2019. The researchers showed that these cases were concentrated in the Wuhan market, unlike those recorded in the following ones month, which coincides with high-density neighborhoods. , which shows the spread of the virus.

In addition, among the cases studied, people who are not directly connected to the market live closer to it than those who work there or have recently visited it. This indicates that they may have been infected due to their proximity to this area.

The researchers also analyzed samples taken from the market in January 2020, for example from a cage or trolley. Their analysis showed that Sars-Cov-2 positive samples were concentrated in the southwest of the market, where live animals (including raccoon dogs, a species of badger, fox, etc.). The animal that could be the intermediary between bats, carriers of the coronavirus, and humans has not yet been identified.

Reduce future risks

The second study is based on the analysis of the genome of the virus infected in these first cases. He concluded that two lineages of the virus, A and B existed before February 2020. And that these two lineages likely resulted from two separate human transmission events, both in the Wuhan market.

Previous studies have suggested that the B line evolved from the A line. Going forward, scientists emphasize that it is important to understand where the animals sold in the Wuhan market come from, in order to minimize the risks of future

If gray areas remain, the researchers point out that the information available on the start of this pandemic is actually very detailed. “There is this general feeling that there is no information that can tell us anything about the origins of the Covid-19 pandemic.commented Kristian Andersen. “It’s just wrong.»

China has often been accused of withholding information or failing to fully cooperate with international investigations. Understanding how this pandemic started is important to help prevent similar future events, and could potentially save millions of lives. “Pandemics do not require blame, but they do require understandingconcluded Kristian Andersen.

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