Genetic ghosts suggest Covid’s market origins

A team of scientists say it is “beyond reasonable doubt” the Covid pandemic started with infected animals sold at a market, rather than a laboratory leak.

They were analysing hundreds of samples collected from Wuhan, China, in January 2020. The results identify a shortlist of animals – including racoon dogs, civets and bamboo rats – as potential sources of the pandemic.
Despite even highlighting one market stall as a hotspot of both animals and coronavirus, the study cannot provide definitive proof. The samples were collected by Chinese officials in the early stages of Covid and are one of the most scientifically valuable sources of information on the origins of the pandemic.

An early link with the Huanan Seafood Wholesale Market was established when patients appeared in hospitals in Wuhan with a mystery pneumonia. The market was closed and teams swabbed locations including stalls, the inside of animal cages and equipment used to strip fur and feathers from slaughtered animals. Their analysis was published last year, and the raw data made available to other scientists. Now a team in the US and France says they have performed even more advanced genetic analyses to peer deeper into Covid’s early days.

It involved analysing millions of short fragments of genetic code – both DNA and RNA – to establish what animals and viruses were in the market in January 2020. “We are seeing the DNA and RNA ghosts of these animals in the environmental samples, and some are in stalls where [the Covid virus] was found too,” says Prof Florence Débarre, of the French National Centre for Scientific Research. The results, published in the journal Cell, highlight a series of findings that come together to make their case.

It shows Covid virus and susceptible animals were detected in the same location, with some individual swabs collecting both animal and coronavirus genetic code. This is not evenly distributed across the market and points to very specific hotspots. “We find a very consistent story in terms of this pointing – even at the level of a single stall – to the market as being the very likely origin of this particular pandemic,” says Prof Kristian Andersen, from the Scripps Institute in the US.

The lab-leak theory argues that instead of the virus spilling over from wildlife, it instead came from the Wuhan Institute of Virology (WIV), which has long studied coronaviruses. It is located a 40-minute drive away from the market. The US intelligence community was asked to weigh up the likelihood of a leak – either accidental or deliberate. Prof Andersen said: “To many this seems like the most likely scenario – ‘the lab is right there, of course it was the lab, are you stupid?’. I totally get that argument.” However, he says there is now plenty of data that “really points to the market as the true early epicentre” and “even locations within that market”. Identifying the animals that could have been the source of the pandemic does provide clues to where scientists could look for further evidence of an animal origin.
 
 
 
 
 
 
 

Rawr

Article URL : https://www.bbc.co.uk/news/articles/cy8095xjg4po