Two years after the start of the pandemic, the origin of the Covid that torments the world still remains a mystery

WASHINGTON: Nearly two years into the COVID-19 pandemic, the origin of the virus plaguing the world remains shrouded in mystery.

Most scientists believe it originated in nature and jumped from bats to humans, either directly or through another animal. Others theorize that it escaped from a Chinese laboratory.

Now, as the global death toll from COVID-19 tops 5.2 million on the second anniversary of the first human cases, a growing number of scientists are trying to focus on what they see as the most plausible “zoonotic”, or animal-to-human, theory, in hopes that what is learned will help humanity fend off new viruses and variants.

“The lab leak scenario is getting a lot of attention, you know, on places like Twitter,” but “there’s no evidence that this virus was in a lab,” said IAAF scientist Stephen Goldstein. University of Utah, who, along with 20 other people, wrote an article. in the journal Cell in August presenting animal evidence.

Michael Worobey, an evolutionary biologist at the University of Arizona who contributed to the article, said he always thought zoonotic transmission was more likely than a lab leak, but that he had signed a letter with other scientists last spring saying both theories were viable.

Since then, he said, his own research and that of others has made him even more confident about the animal hypothesis, which is “just much more supported by the data.”

Last month, Worobey released a timeline of COVID-19 linking the first known human case to the Huanan Seafood Wholesale Market in Wuhan, China, where live animals were sold.

“The idea of ​​a lab leak is almost certainly a huge distraction that distracts from what really happened,” he said.

Others are not so sure. Over the summer, a review ordered by President Joe Biden showed that four US intelligence agencies believed with low confidence that the virus was originally transmitted from an animal to a human, and one agency believed with low confidence. moderate that the first infection was related to a laboratory.

Some proponents of the lab leak hypothesis have speculated that researchers were accidentally exposed due to improper safety practices while working with samples from nature, or possibly after creating the viruses in the laboratory.

US intelligence officials have dismissed suspicions that China developed the virus as a bioweapon.

The continued search for answers has stoked tensions between the United States and China, which has accused the United States of scapegoating it for the disaster. Some experts fear that the origins of the pandemic will never be known.

The scientists said in the Cell paper that SARS-CoV-2, which causes COVID-19, is the ninth documented coronavirus to infect humans. All the previous ones came from animals.

This includes the virus that caused the 2003 SARS outbreak, which has also been linked to markets selling live animals in China.

Many researchers believe wild animals were intermediate hosts of SARS-CoV-2, meaning they were infected with a bat coronavirus that then evolved. Scientists searched for the exact bat coronavirus involved and in September identified three viruses in bats in Laos more similar to SARS-CoV-2 than any known viruses.

Worobey suspects that the raccoon dogs were the intermediate host. The fox-like mammals are susceptible to coronaviruses and were sold alive in the Huanan market, he said.

“The gold standard evidence for an animal origin” would be an infected animal from there, Goldstein said. “But as far as we know, the market has been emptied.”

Earlier this year, a joint report by the World Health Organization and China called transmission of the bat virus to humans from another animal the most likely scenario and a lab leak “extremely unlikely”.

But that report also cast doubt by identifying the first known case of COVID-19 as an accountant who had no connection to the Huanan market and who first showed symptoms on Dec. 8, 2019. Worobey said Proponents of the lab leak theory point to this case in claiming the virus escaped from a Wuhan Institute of Virology facility near where the man lived.

According to Worobey’s research, however, the man said in an interview that his December 8 illness was actually a dental issue and that his COVID-19 symptoms began on December 16, a date confirmed in the company’s records. ‘hospital.

Worobey’s analysis identifies an earlier case: a vendor in Huanan Market who contracted COVID-19 on December 11.

Experts fear that the same type of virus transmission from animals to humans could trigger new pandemics – and make this one worse.

Since the outbreak of COVID-19, many types of animals have been infected, including pet cats, dogs, and ferrets; zoo animals such as big cats, otters and non-human primates; ranch mink; and white-tailed deer.

Most contracted the virus from people, according to the US Centers for Disease Control and Prevention, which says humans can transmit it to animals through close contact, but the risk of animals transmitting it to humans is low. .

Another fear, however, is that the animals could release new virus variants. Some wonder if the omicron variant started out that way.

“Around the world, we could have animals potentially incubating these variants even if we have control over (COVID-19) in humans,” said David O’Connor, a virology expert at the University of Wisconsin-Madison. “We’re probably not going to do a big giraffe vaccination program anytime soon.”

Worobey said he was looking for genetic fingerprints that could indicate whether the omicron was created when the virus jumped from a human to an animal, mutated, and then returned to humans.

Experts say preventing zoonotic diseases will require not only cracking down on illegal wildlife sales, but also making progress on major global issues that increase risky human-animal contact, such as the destruction housing and climate change.

Failure to fully investigate the animal origin of the virus, the scientists said in the Cell paper, “would leave the world vulnerable to future pandemics resulting from the same human activities that have repeatedly put us on a collision course with new viruses”.

But further investigation is blocked by superpower politics. Lawrence Gostin of Georgetown University said there had been a “bare knuckle fight” between China and the United States.

“The politics around the origins investigation has literally poisoned the well of global cooperation,” said Gostin, director of the WHO Collaborating Center on National and Global Health Law. “Politics has literally been toxic.”

An AP investigation last year found that the Chinese government strictly controls all research into the origins of COVID-19 and promotes fringe theories that the virus may have originated outside the country.

“It’s a country that is instinctively very closed, and it was never going to allow foreigners unhindered access to its territory,” Gostin said.

Still, Gostin said there was one positive development that came out of the investigation.

The WHO has formed an advisory group to look into the origins of the pandemic. And Gostin said that while he doubts the panel will solve the mystery, “they will have a group of highly qualified scientists ready to deploy in an instant during the next pandemic.”

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