Two new studies published in the journal Science point to the Wuhan market in China as the epicenter of covid-19. This market’s main activity is the trade of wild animals.
Scientists Michael Worobey and Jonathan Pekar performed spatial and environmental analyses, as well as molecular studies to provide evidence that the Huanan Market in Wuhan was the early epicenter of the SARS-CoV-2 pandemic.
According to Michael Worobey, an evolutionary biologist, professor, director of the Department of Ecology and Evolutionary Biology at the University of Arizona and in charge of the first study, which used mapping tools and social network reports, SARS-CoV-2 was present in the live animals that were sold in the Huanan market at the end of 2019.
He, together with his work team, determined that the first cases of covid-19 appeared in the market, among sellers and buyers who sold and/or acquired live animals. To do this, they mapped the first cases that did not have a direct connection to the market and discovered that these people lived or worked very close to the place, confirming the hypothesis that Huanan was the epicenter of the pandemic.
Kristian Andersen, a professor in the Department of Immunology and Microbiology at Scripps Research who led the second molecular-focused study, said they believe there were two separate viruses circulating in the animals, both of which spread to people.
These viruses have been designated A and B and are believed to have resulted from at least two separate events of interspecies transmission to humans.
The eight cases of covid-19 detected before December 20 were from the western side of the market, where mammal species were also sold. Proximity to five stalls selling live or recently slaughtered animals predicted human cases.
The researchers suggest that the first animal-to-human transmission occurred on November 18, 2019, and came from the B lineage. This type of B lineage was only found in people with a direct connection to the Huanan market.
Scientists believe that lineage A was introduced to humans from an animal within weeks or even days of infection with lineage B. Lineage A was found in humans who lived or stayed near the area.
As with other coronaviruses, the emergence of SARS-CoV-2 was likely the result of multiple zoonotic events.
At the moment it has not been determined whether other factors such as the species of a certain animal or the sanitary measures of the place influenced the appearance of the virus. However, this would mean a great advance for science, because by knowing where and how the virus was produced, a total cure could be found.