Chinese scientists have released the long-awaited genetic analysis of samples and swabs collected in early 2020 from the Huanan Seafood Market, the initial epicenter of the pandemic.
In the study, published Wednesday in Nature, the authors identified wild animals (including raccoon dogs) that are susceptible to SARS-CoV-2 infection, among the large number of genetic traces from SARS-CoV-2 and humans. ) existed in the market. But the overall analysis is flawed, pointing to the presence of animals that were almost certainly never on the market, such as giant pandas, chimpanzees and Atlantic gray seals. The authors continue to downplay the possibility that the virus spread from wildlife to humans in crowded markets was the spark that ignited the pandemic. I repeatedly put forward the hypothesis that I support. In other words, the virus was delivered to the market via humans or frozen food, and the bustling venue became a breeding ground for infection.
Still, publishing data is important, and it takes a long time.Samples were collected from January 1 to March 30, 2020, but the survey draft and Several Preprints reported that SARS-CoV-2 was abundant in human genetic material from samples, indicating that the virus had previously been prevalent among market populations. The authors, led by scientists from the China Center for Disease Control and Prevention (China CDC), noted that they also tested several animals on the market (mainly rabbits, feral cats, and snakes), but all had SARS. – was negative for CoV-2.
pending data
Until last month, three years after the samples were collected, more genetic information was revealed from those samples. In preparation for publication in Nature, a Chinese CDC scientist quietly uploaded previously unpublished metagenomic data from the samples to his public genetic database called GISAID sometime in January. In early March, a group of independent international scientists became aware of the data, eagerly downloaded it, began analyzing it, and contacted scientists at the China CDC about possible collaborations. His CDC scientists in China responded by withdrawing their data from publication, and GISAID publicly accused international researchers of violating their terms of use. firm denial.
However, amid controversy over data access, the international group published a preliminary analysis of the data, but did not release the underlying genetic data themselves to avoid “scooping” their Chinese colleagues. , its preliminary analysis showed that environmental samples from the market were not only positive for SARS-CoV-2 and human genetic material, but also susceptible, as the 2022 preprint suggested. We have shown that wildlife is rife with genetic imprints, including those known to be SARS-CoV-2 infections, such as raccoon dogs.
The study was led by Michael Worobey, an evolutionary biologist at the University of Arizona. Christian Andersen, a virologist at the Scripps Research Institute in California. And theorist Florence Debarre, an expert in evolutionary biology at the French national research institute CNRS, has provided the first genetic evidence linking SARS-CoV-2-positive samples, humans, and susceptible wildlife on the market. bottom.
This analysis cannot determine whether animals became infected with the pandemic virus or, if so, whether animal-to-human or human-to-animal transmission occurred. Therefore, it is not possible to determine conclusively how the pandemic started. But then, as many virologists and infectious disease experts have pointed out, if a natural spillover event sparked a pandemic, this close confluence of genetic material in questionable markets at the epicenter of early cases could lead to a pandemic. Admixture is exactly the type of genetic evidence scientists expect. Discovered after the fact. Such markets, where wildlife zoos are crowded close to humans, are known to act as hotbeds for viral adaptation and spillover risks.
In particular, Worobey and his colleagues focused on one sample (Q61 or env_0576) from a cart that was itself full of raccoon dog genetic material, surrounded by a high density of SARS-CoV-2-positive samples. The researchers found that the sample contained 1,252 he gene segments, 100% identical to the raccoon dog genome, and none of the human genomes were a perfect match. This finding suggests that the SARS-CoV-2 present may be from raccoon dogs rather than humans.
