Two studies provide more evidence that the novel coronavirus pandemic originated in a market in the Chinese city of Wuhan where live animals were sold, further supporting the theory that it emerged in the wild rather than being created in a lab, reports Associated Press. 

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The research, published in the journal Science, suggests that the wholesale seafood market may have been an early epicenter of the outbreak, which has so far killed nearly 6.4 million people worldwide. 

Scientists have concluded that the virus that causes COVID-19 was likely transmitted from animals to humans on two separate occasions.

"All of this evidence tells us the same thing -- it points right to this particular market in downtown Wuhan," said Christian Anderson, a professor in the Department of Immunology and Microbiology at the Scripps Research Institute in San Diego and a co-author of one of the studies. "I myself was completely convinced the virus leaked from a lab until we looked at the facts much more closely."

An American scientist believes that the coronavirus most likely started from the animal market in Wuhan

In a study that included data collected by Chinese scientists, a team of specialists from the University of Arizona used mapping tools to estimate the locations of more than 150 of the earliest reported cases of COVID-19 since December 2019. Similarly, experts mapped cases from January and February 2020 using a social media app created for infected people in need of support. 

"It turns out that when we were able to look at this extreme pattern, the highest density of cases was both extremely close to and in the center of that market. Crucially, this holds true for all cases in December 2019." , as well as for those with no known connection to the market. And this is an indication that the virus started to spread among people who worked in the market, but then went to the local community," the scientists say.

Professor Anderson said they also found clusters in the marketplace, which were "very, very specific to the places" where we now know people sell wildlife.

A new bacterium!

It was found in turtles in Wuhan

In the other study, the specialists analyzed the genomic diversity of the virus in and outside of China, starting with the earliest sampled genomes from December 2019 and continuing through mid-February 2020. 

They find that two lines - A and B - mark the beginning of the pandemic in Wuhan.

Study co-author Joel Wertheim, an expert in viral evolution at the University of California, San Diego, pointed out that lineage A is genetically similar to bat coronaviruses, but lineage B appears to have started to spread earlier in humans, especially in the marketplace.

"I realize it sounds like I just said that a once-in-a-generation event has happened twice in short succession," Wertheim said.

But certain conditions were present - people and animals in close proximity and a virus that can spread from animals to people and from person to person, he adds.

Many scientists believe that the virus was transferred from bats to humans directly or through another animal.

But in June, the World Health Organization (WHO) recommended a deeper investigation into whether the cause could be a laboratory accident.

Critics said the WHO was too quick to dismiss the laboratory leak theory.

China has said claims that COVID-19 may have leaked from its laboratory are false

“Have we disproved the lab leak theory?

No, we have no evidence,” Anderson said.

"The important thing here is that there are possible scenarios and there are plausible ones.

It should be understood that possible does not mean equally probable.'

The origin of the pandemic still remains controversial.

Some experts believe that a laboratory accident is more likely, while others remain open to both possibilities, BTA adds. 

Matthew Aliotta, a researcher at the University of Minnesota College of Veterinary Medicine, said the two studies "go some way to hopefully putting an end to the lab leak hypothesis."

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