Scientists push against Covid Lab leak theory

[ad_1]

In the latest barrage of controversy over the origins of the coronavirus, a group of scientists this week presented a review of scientific findings they said show natural animal-to-human spread is more a potential cause of the pandemic than a lab accident. .

Among other things, the scientists point to a recent report showing that markets in Wuhan, China, sold live animals susceptible to the virus, including palm civets and raccoon dogs, in the two years before the pandemic began. They note the striking similarity between the emergence of Covid-19 and other viral diseases that have arisen through natural fallout, and point to a variety of newly discovered viruses in animals that are closely related to the virus that caused the new epidemic.

Retreats are taking place among scientists as intelligence agencies work with a deadline of the end of the summer to provide President Biden with an assessment of the origin of the pandemic. There is now a split among intelligence officials over the most likely viral origin scenario.

The new paper, which was published online on Wednesday but has not yet been published in a scientific journal, was written by a team of 21 virologists. Four of them also collaborated on a research paper published in 2020 in Nature Medicine that largely dismissed the possibility that the virus could become a human pathogen through laboratory manipulation.

In the new paper, scientists provide more evidence in favor of transmission of the virus from an animal host outside the laboratory. An important point in support of natural origin is the “strange similarity” between the Covid and SARS epidemic, said Joel Werthem, a virologist at the University of California, San Diego, and co-author. He said both viruses emerged in China in late autumn, with the first known cases appearing near animal markets in cities – Wuhan in the case of Covid, and Shenzhen in the case of SARS.

In the SARS epidemic, the new paper notes that scientists eventually traced the origin to viruses that infected bats as far from Shenzhen.

Based on the distribution of viruses similar to the novel coronavirus across Asia, Dr. Werthem and colleagues expect that the origin of SARS-CoV-2 will also be distant from Wuhan.

Since it first emerged in the final months of 2019, the viral culprit for this epidemic has not been found naturally in any animal.

In May, another team of 18 scientists published a letter arguing that the possibility of a lab leak should be taken seriously, because there was little evidence in favor of the natural origin of the coronavirus or a lab leak. Wuhan, where the epidemic was first documented, is home to the Wuhan Institute of Virology, or WIV for short, where researchers have studied coronaviruses from bats for years.

One of the signatories to the May 2021 letter, Michael Worby of the University of Arizona, has become a co-author of the new research paper that claims natural repercussions.

He said his opinions have evolved as more information has emerged. Among other reasons for turning Dr. Worubi is the growing evidence around the Huanan animal market in Wuhan. When the epidemic first appeared in Wuhan, Chinese officials tested hundreds of samples from animals sold in the market and found no coronavirus in any of them.

But last month, a team of researchers provided an inventory of 47,381 animals from 38 species that were sold in Wuhan markets between May 2017 and November 2019. It included species such as civets and raccoon dogs that could act as intermediate hosts for coronaviruses.

Dr. Woroby called the study a “game-changing paper”.

He also indicated the timing of the first cases of Covid-19 in Wuhan. “The Huanan market is at the epicenter of the outbreak, with subsequent cases spreading out into space from there,” Dr. Wurubi said in an email.

“There are no early cases anywhere near WIV, which has been the focus of most speculation about the possibility of lab escape,” he said.

However, other scholars say such arguments are speculative, and that the new revision is mostly a restatement of what was already known.

“Essentially, it really boils down to an argument that since almost all previous pandemics have been of natural origin, this must also be a pandemic,” said David Rellman, a microbiologist at Stanford University who organized the Mayo Letter to Science.

He indicated that he did not object to the hypothesis of natural origin as a reasonable explanation for the origin of the pandemic. But Dr. Reelman believes the new paper provides “a selective sample of findings to discuss one aspect.”

Dr. Worby and colleagues also provide evidence in their new paper against the idea that so-called gain-of-function research that intentionally alters virus function may have played a role in the epidemic. The researchers argue that the coronavirus genome shows no convincing signs of its manipulation. And the diversity of coronavirus scientists found in Asian bats may be the evolutionary source of Covid-19.

But Richard Ebright, a molecular biologist at Rutgers University and a constant critic of attempts to downplay the possibility of leaks in the lab, said this was a straw man’s argument.

Dr. Ebright said it is possible that a WIV lab worker contracted the coronavirus on a field expedition to study bats or while processing the virus in the lab. He argued that the new paper failed to address such possibilities.

“The review does not advance the discussion,” said Dr. Ebright.

[ad_2]