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Scientists parse another clue to possible origin of Covid-19 as WHO says all possibilities are ‘on the table’ | CNN


The search for the origins of the Covid-19 pandemic has intriguing new clues.

New analysis of collected genetic material From January to March 2020, animals at the Huanan Seafood Market in Wuhan, China, were tested positive for SARS-CoV-2, the coronavirus that causes Covid-19. DNA was discovered. A significant amount of its DNA appears to belong to an animal known as a raccoon dog, which is known to be traded on the market, according to World Health Organization officials who addressed the new evidence at a news briefing on Friday. .

The connection to the raccoon dog came to light after Chinese researchers shared raw genetic sequences taken from swab specimens collected at the market early in the pandemic. The sequence was uploaded to the data sharing site GISAID in late January 2023, but was recently removed.

An international team of researchers noticed them and downloaded them for further study, a WHO official said Friday.

The new findings, which have yet to be published, do not solve the question of how the pandemic started. We do not prove that it was an animal that infected humans.

However, the virus cannot survive in the environment outside the host for long, so the discovery that the raccoon dog’s genetic material and the virus’s genetic material were so mixed together raises the possibility that the virus was a carrier. strongly suggested. analysis.led the analysis By Kristian Andersen, immunologist and microbiologist at Scripps Research. Edward Holmes, virologist at the University of Sydney. Evolutionary biologist at the University of Arizona, Michael Wolrobie. These three of his scientists, who have been digging into the origins of the pandemic, were interviewed by a reporter for The Atlantic. CNN reached out to Andersen, Holmes and Worobbie for comment.

Detail is An international analysis was first reported on Thursday Atlantic.

New data has come to light as Republicans in Congress launched an investigation into the origins of the pandemic. Research so far It provided evidence that the virus likely originated naturally in the market, but could not point to a specific origin.Several US agencies, including recent U.S. Department of Energy Evaluationsaid the pandemic was likely caused by Laboleak in Wuhan.

At a news briefing on Friday, WHO Director-General Tedros Adhanom Ghebreyesus said the organization first became aware of the sequence on Sunday.

“We contacted China’s CDC shortly after we became aware of this data and requested that it be shared with the WHO and the international scientific community so that it can be analyzed,” Tedros said.

The WHO also convened a scientific advisory group on the origin of novel pathogens, known as SAGO, which has been investigating the origins of the pandemic, to discuss the data on Tuesday. The group heard from Chinese scientists who originally studied the sequences and from a group of international scientists who are reviewing them.

WHO experts said at a briefing on Friday that the data were inconclusive.

“These data do not provide a definitive answer to the question of how the pandemic started, but all the data are important to get us closer to that answer.”

What the sequencing proves is that China has more data that may be related to the origins of the pandemic that has yet to be shared with the world, according to WHO officials.

“This data could have been shared three years ago and should have been shared,” Tedros said. “We continue to urge China to be transparent in data sharing, conduct necessary investigations, and share results.

“Understanding how the pandemic began remains a moral and scientific imperative.”

CNN reached out to the Chinese scientist who originally analyzed and shared the data, but received no reply.

Chinese researchers affiliated with the country’s Centers for Disease Control and Prevention shared their own analysis of the samples in 2022. In that preprint study, posted last year, “an animal host for SARS-CoV2 cannot be inferred.”

research After examining 923 environmental samples from seafood markets and 457 samples from animals, we found 63 environmental samples that were positive for the virus that causes Covid-19. Most were taken from the western end of the market. In 2022, the Chinese authors found that neither refrigerated and frozen products for sale nor animal samples taken from live feral animals roaming markets were positive.

After looking at the DNA of different species in environmental samples, the Chinese authors found links only to humans, but not to other animals.

Recently, an international team of researchers Scientists used an advanced genetic technique called metagenomics to review the genetic material of samples swabbed in and around market stalls and found a significant amount of DNA belonging to the raccoon dog. He said he was surprised to find it. A small animal resembling a fox. Raccoons can be infected with the virus that causes Covid-19 and are high on the list of animals suspected to host the virus.

“What they found was molecular evidence that animals were being sold at the market. “The region was susceptible to SARS-CoV2 infection and some of those animals included raccoon dogs,” said Maria Van Kerkhove, WHO’s Covid-19 technical director, at a briefing on Friday. said.

“This doesn’t change our approach to studying the origins of Covid-19. It just shows that there is more data and we need to fully share the data,” she said. Told.

“All hypotheses remain under consideration,” said Van Kerkhove, until more evidence is available for the international scientific community to consider.

Some experts have found the new evidence compelling, if not entirely convincing, about the origins of the market.

“The data further point to the origin of the market,” said Andersen, an evolutionary biologist at Scripps Research who attended the WHO. told the magazine he was one of the scientists analyzing the new data. chemistry.

Claims about the new data quickly sparked controversy in the scientific community.

François Ballou, director of the Institute of Genetics at University College London, said the new analysis has not yet been publicly posted for scientists to scrutinize, but the fact that it came to light in news reports is a cautionary tale. said to be necessary.

“Such articles are not really helpful as they only further polarize the discussion,” Balloux posted in the following thread twitter“Those who are convinced it came from a zoonotic disease read it as the final proof of their beliefs, and those who are convinced it was a laboratory leak attribute the weakness of the evidence to an attempt to cover it up.” will be interpreted as

Other experts not involved in the analysis said the data could be key to showing that the virus is of natural origin.

Felicia Goodrum is an immunobiologist at the University of Arizona who recently published a review of all available data on the various theories behind the origin of pandemics.

Goodrum says the strongest evidence for natural spillovers comes from isolating the virus that causes Covid-19 from animals on the market in 2019.

“Obviously it’s not possible, because you can’t go back in time beyond what you did the sequencing for, and the animal wasn’t there at the time the sequence could be collected. For me, this is the next best thing.” That’s right,” Goodrum said in an email to CNN.

At a WHO briefing, Van Kerkhove said the Chinese CDC researchers uploaded the sequences to GISAID as they were updating the original study. She said her original paper is in the process of being updated and resubmitted for publication.

“GISAID informed me that the data from China’s CDC has been updated and expanded,” she said.

Van Kerkhov said Friday that what the WHO wants to be able to do is find out where the animals came from. were they wild? were they farmed?

In the course of its investigation into the origins of the pandemic, she said the WHO had repeatedly asked China for research to trace animals back to their farms of origin. She also said the WHO had asked for blood tests on people who worked at the market and on animals that may have come from the farm.

“Please share your data,” Dr. Mike Ryan, executive director of the WHO’s Health Emergency Program, said Friday to scientists around the world who may have relevant information. “If you let science do the work, it will give you the answers.”

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