Rabat – After two years of scientific research, two recent studies confirm that the COVID-19 epidemic originated in the seafood and wildlife market of the Chinese city of Wuhan, pointing to the virus’s most likely animal origin.
Published on Tuesday in the renowned journal Science, the two peer-reviewed studies on the virus’ origin confirm that SARS-CoV-2, the virus that causes COVID-19, was found in live animals sold at the Huanan market in late 2019.
The first study is a geographic analysis that shows that the first COVID cases discovered in December 2019 were concentrated in the market. It demonstrates that the Sars-Cov-2 positive samples were concentrated in the southwestern part of the market, precisely where animals live.
Although the virus’s origin is unknown, the research confirms that the first animal-to-human transmission appears to have occurred around November 18, 2019.
Although only about 50 of the hundreds of patients hospitalized with COVID-19 in Wuhan had a direct, traceable connection to the market, this study found that a large number of early patients who had no direct link to the market — did not work or shop in the market — turned out to reside nearby.
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The second study is based on genomic analysis of the virus that infected the initial patients, in which the researchers detected two viral lineages they named the A and B lineages of the virus.
According to the findings, these two lineages existed prior to February 2020 and are most likely the result of two separate human transmission occurrences, both in the Wuhan market.
The research found that lineage A, which was discovered in samples from people who lived near the market, was introduced to humans by animals days or weeks later.
Meanwhile, it also confirms that the first animal-to-human leap occurred from lineage B around November 18, 2019, which was only found in those who had a direct link to the market.
