Scientists discover the origin of Covid19? Here is what is thought to be the source from which the deadly coronavirus pandemic began

Two newly published studies take completely different approaches but reach the same conclusion: The Huanan food market in Wuhan, China, was most likely the epicenter of the coronavirus.

The studies were posted online as preliminary information in February, but have now undergone peer review and were published Tuesday in the journal Science.

In one, scientists from around the world used mapping tools and social media reports to do a spatial and environmental analysis. They suggest that although “the exact circumstances remain unclear,” the virus was probably present in live animals sold on the market in late 2019. The animals were kept in close proximity to each other and could have easily exchanged microbes. However, the study does not determine which animals may have been sick.

The researchers determined that the earliest cases of Covid-19 were concentrated in the market among vendors who sold these live animals or people who shopped there. They believe there were two separate viruses circulating in animals that spread to humans.

“All eight cases of COVID-19 detected before December 20 were from the western side of the market, where mammal species were also sold,” the study says. Proximity to five stalls selling live or recently slaughtered animals was predictive of human cases.

“The clustering is very, very specific,” study co-author Kristian Andersen, a professor in the Department of Immunology and Microbiology at Scripps Research, said Tuesday.

The “remarkable” pattern that emerged from mapping these cases was very clear, said another co-author, Michael Worobey, head of the Department of Ecology and Evolutionary Biology at the University of Arizona.

The researchers mapped the earliest cases that were unrelated to the market, Worobey noted, and those people lived or worked near the market.

“This is an indication that the virus started to spread to people working in the market, but then it started to spread … to the surrounding local community as vendors went to local stores, infected people working in those stores,” Worobey said.

The next study takes a molecular approach and looks to determine when the first coronavirus infections passed from animals to humans.

The earliest version of the coronavirus, this study shows, probably came in different forms that scientists call A and B. The lineages were the result of at least two transmission events between species to humans.

The researchers note that the first animal-to-human transmission probably occurred around November 18, 2019, and came from lineage B. They found lineage B only in people who had a direct connection to the Huanan market.

The authors believe that lineage A was introduced to humans from an animal within weeks or even days of infection by lineage B. Lineage A was found in samples from people who lived or stayed near the market.

“These findings indicate that it is unlikely that SARS-CoV-2 was widely circulating in humans before November 2019 and define the narrow period between when SARS-CoV-2 first jumped into humans and when the first cases were reported of COVID-19. “, says the study. “As with other coronaviruses, the emergence of SARS-CoV-2 likely resulted from multiple zoonotic events.”

The likelihood of such a virus emerging from two separate events is low, agreed co-author Joel Wertheim, an assistant professor of medicine at the University of California, San Diego.

To reduce the chances of future pandemics, researchers hope they can determine exactly which animal may have been infected first and how.

Andersen said that while we can’t prevent outbreaks, collaboration among the world’s scientists could be the key to making the difference between a disease with a small impact and one that kills millions.

“The big question we have to ask ourselves is — the next time this happens, because it will — how do we go from early detection of that outbreak and preventing that outbreak from becoming a pandemic?”

Source: CNN

top channel