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Was China’s Huanan market epicentre of Covid start? WHO’s top scientist answers

Did Covid-19 emerge from China’s Wuhan district? Maria Van Kerkhove, the top infectious disease epidemiologist, said several studies since March 2021 have identified animal species that were sold at China’s Wuhan markets that are susceptible to SARS-CoV-2 Covid infection.

As per Kerkhove, the Huanan market in China’s Wuhan district indeed played a “very important role” in this pandemic, and she would urge further studies continue to be needed to trace back animals sold there prior to the first detected cases.

Kerkhove said, however, there’s still much uncertainty and that more research in this area should be welcomed. “We need more serology in specific populations and to ensure we further study earlier suspected cases into November 2019 and possibly earlier,” she added.

She said for SARS-CoV-2 more studies are needed to better understand the exposures of the earliest known and even earlier potential cases. “Data from multiple studies are needed — it’s like detective work (and I mean this without a police reference),” she quipped.

2 latest studies hint towards Wuhan market:

Notably, scientists have released two latest studies that give some clues about how the Covid-19 virus had first emerged. These studies, which are still in preprints, are yet to be peer-reviewed.

While one of the two studies indicate SARS-CoV-2 virus saw its first outbreak in a massive seafood wholesale market in the Huanan region of Wuhan district in China, the second study shows the Covid virus must have emerged from two zoonotic events.

Also read: Can COVID subvariant cause serious diseases? Experts explain severity

What do studies reveal?

Covid-19 virus may have emerged from 2 zoonotic events:

The first study that’s still preprint shows that the Covid-19 virus may have emerged “very likely” from at least two zoonotic events. Analysing the pattern and origin of the genomic diversity of SARS-CoV-2 early pandemic, the study reveals SARS-CoV-2 genomic diversity prior to February 2020 comprised only two distinct viral lineages—denoted A and B—with no transitional haplotypes.

“Novel phylodynamic rooting methods, coupled with epidemic simulations, indicate that these two lineages were the result of at least two separate cross-species transmission events into humans,” it shows. The first zoonotic transmission likely involved lineage B viruses and occurred in late-November/early-December 2019, while lineage A likely occurred in weeks of the first event. “These findings define the narrow window between when SARS-CoV-2 first jumped into humans and when the first cases of COVID-19 were reported,” it showed.

Also read: Declining cases of Covid-19 and Omicron signal the end of pandemic? Expert speaks

Study 2: Human, an unambiguous epicentre of the Covid-19 pandemic

Another study suggested that the “human seafood wholesale market in China’s Wuhan district was the site of origin of the Covid-19 pandemic.

Despite strong epidemiological links and the documented presence of SARS-CoV-2 susceptible animals, the roles of the Human Seafood Wholesale Market in the Covid-19 pandemic remains controversial, it said. 

“By combining spatial and genomic data, we show that both the two early lineages of SARS-CoV-2 have a clear association with the Huanan market. We also report that live mammals, including raccoon dogs, were sold at the market in late 2019 and geospatial analysis within the market show that SARS-CoV-2 positive dispositive evidence for the emergence of SARS-CoV-2 via the live wildlife trade and identify the Huanan market as the unambiguous epicentre of the Covid-19 pandemic,” the study concluded. 

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