Two new studies provide further evidence that the coronavirus pandemic originated in a market in Wuhan, China, where live animals were sold, further reinforcing the theory that the virus appeared in nature rather than escaping a Chinese lab.
The study, published online Tuesday by the journal Science, shows that Huanan’s seafood wholesale market is likely to be the first epicenter of the scourge that has now killed nearly 6. 4 million people worldwide. Scientists conclude that the virus that causes COVID-19, SARS-CoV-2, has most likely spread twice from animals to humans.
“All this evidence tells us the same thing: it’s directly targeting this specific market in the middle of Wuhan,” said Kristian Andersen, a professor in the Department of Immunology and Microbiology at Scripps Research and co-author of one of the studies. “I myself was convinced of the leak from the lab until we examined it very thoroughly and took a closer look at it. “
In one study, which incorporated knowledge gathered through Chinese scientists, University of Arizona evolutionary biologist Michael Worobey and colleagues used mapping equipment to estimate the locations of more than 150 of the first COVID-19 cases reported through December 2019. They also mapped cases from January and February 2020, data from a social media app that had created a channel for other people with COVID-19 to get help.
They asked, “Of all the places where the first instances may have lived, where did they live?And it turned out that when we got a look at that, there was this ordinary trend where the highest density of instances was incredibly close and very market-focused,” Worobey said at a news conference. “Basically, this applies to all instances in December and also to instances with no known connection to the market. . . And this indicates that the virus began to spread among other people who worked in the market and then began to spread in the local community. “
Andersen said they had also discovered clusters of cases within the market, “and that clustering is very, very fast in parts of the market” where they now know that other people were selling wild animals, such as viverrin dogs, that are vulnerable to being inflamed with the coronavirus.
In the other study, scientists analyzed the genomic diversity of the virus inside and outside China’s birth with the first genome samples in December 2019 and through mid-February 2020. They found that two lineages, A and B, marked the birth of the pandemic in Wuhan. Study co-author Joel Wertheim, an expert on viral evolution at the University of California, San Diego, noted that lineage A is more genetically similar to bat coronaviruses, but lineage B appears to have begun to spread earlier in humans, especially in the market.
“Now I realize that it seems like I just said that an exclusive event in a generation happened twice in a row,” Wertheim said. animals to other people and from one user to another. Therefore, “the barriers to overflows have been reduced, so, from our point of view, multiple introductions deserve to be expected,” he said.
Many scientists claim that the virus has passed from bats to humans, either directly or through some other animal. But in June, the World Health Organization advised further investigation to determine whether a twist of fate in the lab may be to blame. Critics had said the WHO had been too quick to dismiss the theory of laboratory leaks.
“Have we refuted the theory of laboratory leaks?No, we didn’t,” said Andersen. no means likely as well. “
The origins of the pandemic remain controversial. For some scientists, a lab leak is most likely more likely and others remain open to either possibility. But Matthew Aliota, a researcher at the University of Minnesota School of Veterinary Medicine, said in his brain that the pair of studies “hopefully puts an end to speculation. “of a laboratory leak. “
“These two studies provide compelling evidence of the naturally developing hypothesis,” said Aliota, who was not involved in either study. Since it is highly unlikely to follow a pattern of an animal that was on the market, “it would possibly be the closest thing to a firearm you can also get. “