Virus Review by Alina Chan and Matt Ridley – Was Covid-19 Really Made in China? | Science and Nature Books

EVer since the first report of coronavirus The origin of Covid-19 in Wuhan, a large city in central China, is controversial. Was Sars-CoV-2 the result of a natural animal-to-human spillover event to give the virus a formal name, or was it the result of laboratory experiments?

Most cases were gathered around a seafood market that also sells wildlife, but did not escape the attention of western intelligence agencies with the Wuhan Institute of Virology (WIV) nine miles south. Nor have researchers at safe biosafety facilities surveyed caves in southern Yunnan for many years. ChinaWe are looking for bats that carry viruses like SARS and isolate genetic material from saliva, urine and feces.

One of these isolates labeled RaTG13 shared 96% of its genome with Sars-CoV-2, revealing that WIV researchers were experimenting with a chimeric version that could infect human cells. At that time, speculation grew. Don’t worry, similar “gain of function” experiments have been conducted at western biosecurity facilities, showing that such gradual changes in pathogenicity can occur naturally. The fact that the outbreak began in the same city as WIV was a non-negligible coincidence. NS Two Chinese researchers “It was very unlikely that bats would fly to the market,” he said.

Alina Chan and Matt Ridley are also confused as to why the virus was first detected in Wuhan, not in Yunnan, 900 miles south, if it was of natural origin. “In every gin joint in every town in the world …” they write. The risk is never higher. If the virus was designed in a Chinese laboratory and deliberately released to the world, it would be a crime of this century.

Wisely, Chan and Ridley don’t go that far. They show their position as advocates of rigorous evidence-based science, writing that “we are not claiming cheating, we are just claiming mistakes.”

Ridley, the most well-known conservative hereditary peer in his skeptical work on climate change, and Chan, a molecular biologist at the Broad Institute in Cambridge, Massachusetts, have the right to scrutinize the evidence. Indeed, we are now concerned about their concerns at the time Public blame Proposals of non-natural origin and claims of viral boredom Any of the features It’s designed. But is this the fair and balanced research the world has been waiting for?

Chan and Ridley are wise writers, and in their “Quest for the Origin of Covid-19”, with the help of an eclectic band of internet detectives, called “Seeker”, into the deepest depressions of cyberspace. Step in. The result is a whodunit of the virus that definitely appeals to armchair detectives and skeptics of scientific legitimacy.

There is only one problem. There is no evidence that Sars-CoV-2 was manufactured.Understand Chan’s claim that he seemed to be pre-adapted to human infections “To the same extent as the late-fashioned SARS”.. This claim is based on a single mutation in a peplomer that appears to “slightly increase” its ability to bind to human receptor cells (Chan and Ridley’s words), until it was first detected in Wuhan. “It suggests that it was” clearly genetically stable. “

However, this can be very misleading. The coronavirus underwent repeated mutations that steadily increased its fitness, as the subspecies’ subsequent alphabetic soup shows. In addition, studies of viruses isolated from the Pangolins, one of the suspected intermediate hosts, have been more efficiently bound to human receptor cells than Sars-CoV-2 and have the ability to adapt further. Suggests. As two major virologists said, the virus was not fully adapted to humans, but “Good enough“.

Another suspicious feature of Sars-CoV-2 is that it has a molecular key known as the furin cleavage site. This allows the receptor protein in human cells to be prize-opened and the infectious process to begin. The same sequence is found in the highly contagious influenza virus and was previously adopted by researchers to modify the Sars peplomer. Chan and Ridley suggest that this is exactly the type of insertion expected to be found in laboratory-modified bat viruses.

However, 21 major scientific experts have recently found that furin sequences are not optimal. “Almost the same” The sequence is found in the coronavirus, which commonly infects humans and cattle.In other words, it has no function Known The bat coronavirus, which can be a product of natural evolution as easily. Needless to say, Chan and Ridley have yet to suggest that this feature of the virus was deliberately inserted. However, it means that there is no way to know.

There is also no way to know if RaTG13 is a progenitor cell of the pandemic virus. In 2013, WIV researchers recovered bat isolates from an abandoned mine in Sumie, Yunnan, near the border with Laos, and removed bat guano from the cave a year ago. A man with a mysterious respiratory illness and three died.

However, 4% genetic differentiation between RaTG13 and Sars-CoV-2 corresponds to 40 years of evolutionary change. Researchers exploring caves in northern Laos subsequently discovered three bat coronaviruses that were more closely associated and more efficiently attached to human cells than early strains of Sars-CoV-2. Did.

This is likely to have emerged naturally when farmers set foot in a cave in Yunnan or Laos in search of Guano, either by passing through another animal host or spilling directly from a bat. Suggests. This is the most frugal explanation and applies to both forensic and epidemiological evidence. Samples recovered from the Wuhan seafood market are identical to human isolates, and most of the original human cases had a history of previous market exposure. In contrast, there is no epidemiological association with Wuhan’s WIV or other research facilities.

Indeed, if scientists can provide evidence of previous infections in the Wuhan market or other Chinese wildlife markets that have sold pangolins, pangolins, and raccoon dogs (most likely intermediate species), cases of natural origin are more likely. Become stronger. Nevertheless, Sars Outbreaks Many animals have been tested positive for sibling human metapneumovirus. In the case of Sars-CoV-2, scientists have yet to reveal evidence of previous infections in the animal. But, as all schoolboys know, lack of evidence is not evidence of lack-it may simply be that the sample has not yet been taken from the appropriate animal.

Of course, the same is true for the lack of evidence of Labreak theory. However, although large pandemics have never been tracked in the laboratory, there are scattered examples of pandemics that began as the transfer of the virus from animals. In other words, zoonotic diseases are the null hypothesis or the default hypothesis. The burden of proof otherwise rests with Chan and Ridley.

Tragedy emerges in their desire to file a plausible proceeding of an accident in the laboratory, how wildlife trade, coupled with global heating and destruction of natural habitats, emerges. Ignoring the much more urgent and compelling story about what to do is increasing the likelihood of a pandemic virus. It’s a story of more likely origin and a scenario that should really relate to us.

Mark Honigsbaum is the author of Pandemic Century