In a pair of comprehensive investigations published over the weekend, scientists asserted that the coronavirus pandemic originated in a big food and live animal market in Wuhan, China, which is home to millions of people.
According to the findings of the study, which included an examination of a wide range of data such as virus genes, market stall maps, and the social media activity of early Covid-19 patients across Wuhan, the coronavirus was very likely present in live mammals sold at the Huanan Seafood Wholesale Market in late 2019 and that the virus had spread to people working or shopping there on two separate occasions.
The studies, which total 150 pages in length, are an important contribution to the discussion concerning the origins of a pandemic that has claimed the lives of roughly six million people throughout the globe since its inception. The issue of whether the epidemic was caused by a spillover from animals sold at a market, a leak from a Wuhan virology lab, or some other event has sparked heated disputes over the best way to prevent the next pandemic.
According to Michael Worobey, an evolutionary biologist at the University of Arizona and a co-author of both new research, “When you look at all of the data together, it paints an exceptionally strong picture that the epidemic originated at the Huanan market.”
Multiple independent experts said that the investigations, which have not yet been published in a scientific publication, offered a persuasive and thorough new examination of the data that was accessible at the time.
Doctor Thea Fischer, an epidemiologist at the University of Copenhagen who was not involved in any of the new investigations, stated, “It’s really persuasive.” The issue of whether the virus came from animals “has now been resolved with a very high degree of evidence, and therefore confidence,” according to the researchers.
Others, on the other hand, pointed out that there were still some holes. Because the new publications did not identify a single animal that was responsible for spreading the virus to people, for example, they were not published.
A virologist at the Fred Hutchinson Cancer Research Center, Dr. Jesse Bloom, remarked, “I believe what they’re suggesting may be accurate.” “However, I do not believe that the quality of the evidence is adequate to conclude that any of these possibilities is correct with certainty.”
Researchers from the Chinese Center for Disease Control and Prevention released an online research on Friday in which they examined the genetic traces of the first environmental samples taken at the market in January 2020.
By the time Chinese researchers came to collect the samples, the market had already been closed and cleaned due to a number of individuals who had been associated to it being ill with what would subsequently be identified as Covid. There were no live market animals remaining.
The researchers swabbed the walls, floors, and other surfaces of the market, as well as meat that was still in the freezers and refrigerators, for traces of the pathogen. They also gathered mice and stray cats and dogs from surrounding the market to put through their paces, and they tested the contents of the sewers outside the market as well. The samples were then tested for genetic signs of coronaviruses that may have been transmitted by humans or animals, according to the researchers.
Despite the fact that the Chinese researchers completed their study more than two years ago, it was not until Friday’s announcement that they were able to publicly reveal the results of their findings. In their paper, they said that the viral samples from the Huanan market comprised two evolutionary branches of the virus known as lineages A and B, both of which had been circulating in early Covid cases in China.
These results came as a complete surprise to the researchers. Lineage B Covid cases seemed to be the only ones associated with the market in the early days of the epidemic in mainland China. Furthermore, since Lineage B seemed to have developed after Lineage A, several researchers hypothesised that the virus only reached the market after spreading across Wuhan and the surrounding area.
However, a recent Chinese research reveals evidence of both lineages in market samples, which calls into question this argument. It seems that the data are consistent with the scenario proposed by Dr. Worobey and his colleagues, in which at least two spillover occurrences happened on the stock exchange.