Scientists Again Link Covid Pandemic Origin to Wuhan Market Animals

The Washington Post reports:

An international team of scientists published a peer-reviewed paper Thursday saying genetic evidence indicates the coronavirus pandemic most likely originated with a natural spillover from an animal or animals sold in a market in Wuhan, China, where many of the first human cases of covid-19 were identified. The paper, which appears in the journal Cell, does not claim to prove conclusively that the pandemic began in the Huanan Seafood Wholesale Market, and it is unlikely to end the acrimonious and politicized debate over the coronavirus's origin... 'The results we see are consistent with infected animals, but we cannot prove that they were,' said Florence Débarre, an evolutionary biologist at the French National Center for Scientific Research and a co-author of the new paper...

Many of the 23 authors of the paper are known to have long supported a market origin for the virus. In an informal report in March 2023, they presented a central feature of the genetic data — the confirmation that animals potentially capable of triggering a pandemic were in the market... The new paper in Cell is longer, more comprehensive, probes a broader range of questions, and includes more data from the market and early-patient cases than the international team's informal 2023 report, Débarre said. Both the earlier and the new reports document that traces of the virus were found clustered in a section of the Huanan Seafood Wholesale Market where genetic traces of animals were also found. Several of those species — raccoon dogs, rabbits and dogs — are known to be susceptible to infection with SARS-CoV-2, the virus that causes covid. Raccoon dogs have also been shown experimentally to be capable of transmitting the virus. A significant element of the new paper is an analysis of when the pandemic began. Scientists can study mutations of the coronavirus, which evolves at a relatively steady rate, to estimate when the millions of genomes deposited in databases had the most recent common ancestor. That genetic evidence points to mid-November 2019 as the most likely time the virus spilled into humans and began spreading, and there could have been two or more spillover events, the researchers said.

'The timing of the origin of the market outbreak is genetically indistinguishable from the timing of the origin of the pandemic as a whole,' the report states. There are many independent lines of evidence pointing to the market as the epicenter of the pandemic, said Kristian Andersen, an infectious-disease researcher at Scripps Research in La Jolla, Calif., and a co-author of the report in Cell. No previous virus spillover has been so well-documented, he said. 'Of any previous outbreak, pandemic, you name it, we don't have this level of granularity,' he said. 'We can narrow it down to a single market, and narrow it down to a section in that market, and maybe even narrow it down to a single stall in that market. That is mind-boggling....' The genetic evidence, the new report contends, supports the hypothesis that SARS-CoV-2 emerged in the same way that SARS-CoV-1 — which sickened people in 2002-2003 but was extinguished before it could cause a full-blown pandemic — is widely believed to have started, from animals sold in a market.

The authors contend the world needs to take more aggressive action to shut down the illegal trade in wildlife to lower the risk of another catastrophic pandemic... There is no evidence that the virus, or its progenitor, was inside a laboratory before the outbreak.... 'To the question — Did it come from a lab or come from a market? — I think we already knew the answer to that,' Andersen said. 'Yep, it's the market. It's natural, as we've previously seen happen.'

One co-author posted a summary on X.com 'If you don't want to read the papers.'

'Early cases centered around the market (not a lab)'
'Environmental swabs that tested positive for SARS-CoV-2 clustered in the corner of the market where animals were sold.'
'There were 2 lineages of SARS2 that spilled over separately at Huanan.'

Read more of this story at Slashdot.