央视“美科学家否认武汉是病毒起源”新闻的英文原文

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英文原文：
Sorry, conspiracy theorists. Study concludes COVID-19 'is not a laboratory construct'
Some have suggested the virus is actually an engineered biological attack.
By Kate Holland

Conspiracy theories claiming COVID-19 was engineered in a lab as part of a biological attack on the United States have been gaining traction online in recent weeks, but a new study on the origins of the virus has concluded that the pandemic-causing strain developed naturally.

An analysis of the evidence, according to the findings first published in the scientific journal Nature Medicine, shows that the novel coronavirus "is not a laboratory construct or a purposefully manipulated virus," with the researchers concluding "we do not believe that any type of laboratory-based scenario is plausible."

"There’s a lot of speculation and conspiracy theories that went to a pretty high level," Dr. Robert Garry, a professor at the Tulane University School of Medicine and one of the authors of the study, told ABC News, "so we felt it was important to get a team together to examine evidence of this new coronavirus to determine what we could about the origin."

Dr. Francis Collins, the director of the National Institutes of Health, supported the study’s findings, writing on his blog, "This study leaves little room to refute a natural origin for COVID-19."

Researchers concluded that the novel coronavirus is not a human creation because it does not share any "previously used virus backbone." It likely arose, the study said, from a recombination of a virus found in bats and another virus, possibly originating from pangolins, otherwise known as scaly anteaters.

COVID-19 is 96% identical to a coronavirus found in bats, researchers said, but with a certain variation that could explain what has made it so infectious.

"We know from the study of other coronaviruses that they’re able to acquire this [variation] and they can then become more pathogenic," Garry told ABC News. "This is a good explanation as to why this virus is so transmittable and has caused this pandemic."

The mutation in surface proteins, according to Garry, could have triggered the outbreak of the pandemic, but it’s also possible that a less severe version of the illness was circulating through the population for years, perhaps even decades, before escalating to this point.

"We don’t know if those mutations were picked up more recently or a long time ago," Garry told ABC News. "It’s impossible to say if it actually was a mutation that triggered the pandemic, but either way, it would have been a naturally occurring process."

And while many believe the virus originated at a fish market in Wuhan, China, Garry said that is also a misconception.

"Our analyses, and others too, point to an earlier origin than that," Garry said. "There were definitely cases there, but that wasn’t the origin of the virus."

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