Researchers reconstructed the early stages of virus spread, the distribution of known cases in humans and mammals susceptible to Sars-CoV-2, by linking them to positive samples taken from the environment.
The Covid pandemic originated in the Wuhan market. The new confirmation comes from an international study published in Science
, which seems to put an end to the diatribe on the origin of the spread of the virus. The researchers reconstructed the early stages of the story, focusing on the distribution of known cases in humans and mammals sensitive to Sars-CoV-2, linking them to positive samples taken from the environment, such as cages. All reconstructions led back to Wuhan’s Huanan Seafood Wholesale Market. ‘Although there is insufficient evidence to define the upstream events and the exact circumstances remain obscure, our analyzes indicate that the spread of the virus arose from the live wildlife trade in China and show that the Huanan market was the epicenter of the pandemic, ”say the authors.
The first foci of pneumonia
The whole world only realized what was happening on December 31, 2019, when the Chinese government notified the World Health Organization of an outbreak of severe pneumonia of unknown aetiology in Wuhan, a city of about 11 million inhabitants. Of the 41 people initially hospitalized with pneumonia, 27 had attended the Huanan market. The first diagnoses of Covid were made in several hospitals, independently, between 18 and 29 December 2019. A subsequent systematic review of all cases notified by Wuhan hospitals as part of the joint WHO-China study showed that 55 of the 168 earliest known cases of Covid were associated with the market. However, even today, the discussion on the origin of the virus divides the scientific community and there is no shortage of experts convinced that Sars-CoV-2 was born in a laboratory.
The transition from animal to human
A second study published in the same journal has instead reconstructed the family tree of Sars-CoV-2 going back to the first two lineages of the virus. The researchers determined that the virus was probably first transferred from animals to humans between 23 October and 8 December 2019. “These results indicate that Sars-CoV-2 is unlikely to have circulated widely in humans before November 2019 and define the narrow window between when the virus first moved to humans and when the first cases were reported. of Covid “.
July 26, 2022 (change July 26, 2022 | 20:54)
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