Analysis of earliest covid-19 cases points to Wuhan market as source

A caller look astatine what we cognize astir the archetypal covid-19 cases shows that the earliest known lawsuit was successful a idiosyncratic who worked astatine the Huanan Market successful Wuhan, which was suspected arsenic the root from the commencement of the pandemic

Health 18 November 2021

By Michael Le Page

A motion pointing to the Huanan Market successful Wuhan, China, wherever radical were infected with the coronavirus successful the aboriginal stages of the covid-19 pandemic

BJ Warnick/Newscom/Alamy

An investigation of what we cognize astir the earliest covid-19 cases has strengthened the lawsuit that the coronavirus pandemic began erstwhile animals astatine the Huanan Market in Wuhan, China passed the microorganism connected to people. Among different things, it concludes that the archetypal lawsuit was a pistillate who worked arsenic a seafood vendor astatine the market, who became sick connected 11 December 2019.

It is wide that the SARS-CoV-2 microorganism derives from bat coronaviruses. What is not wide is where, erstwhile and however it got from bats into people. It has been suspected close from the commencement that unrecorded animals astatine the Huanan Market mightiness beryllium the intermediate host, arsenic the archetypal cases were clustered astir this market.

A World Health Organization study connected the origins of SARS-Cov2, published earlier this year, states that the archetypal idiosyncratic known to person covid became sick connected 8 December and had nary transportation to the market. This was partially wherefore the study that concluded that nary steadfast decision astir the relation of the marketplace could beryllium drawn.

However, this antheral – a 41-year-old accountant surviving 30 kilometres distant from the marketplace – went to infirmary connected 8 December due to the fact that of dental problems and lone developed covid-19 symptoms connected 16 December, says Michael Worobey astatine the University of Arizona successful his analysis.

These dates are confirmed by media interviews with the accountant, infirmary records and a technological paper, Worobey says. That means that the earliest known cases were so linked to the market, with the archetypal being the seafood vendor who became sick connected 11 December.

Why this is not in the WHO report is unclear, arsenic the squad did talk to the accountant. “My conjecture is that they were told that this was the ‘December 8’ diligent and conscionable accepted it arsenic read,” Worobey says. “But it would beryllium absorbing to larn much astir that interview, for sure.”

When asked if their study had got it wrong, a WHO spokesperson said it was hard to remark connected peculiar cases. “The squad did conscionable with immoderate aboriginal patients but those were not epidemiological interviews collecting wellness information that would enactment them successful the timeline,” the spokesperson told New Scientist. “Those interviews were done by Chinese authorities successful 2020.”

Overall, according to the WHO report, a 3rd of 168 retrospectively identified cases successful December had links to the Huanan market. This is successful enactment with what 1 would expect if the marketplace was the source, Worobey says. Because the archetypal SARS-CoV-2 microorganism was highly infectious and could dispersed asymptomatically, galore cases would soon deficiency a nonstop nexus to the source.

However, it has been suggested that this seemingly beardown nexus to the marketplace is owed to bias, due to the fact that erstwhile authorities were alerted connected 29 December they specifically began looking for cases linked to the market.

Worobey says this tin beryllium checked by looking astatine what happened astatine the 3 hospitals wherever doctors archetypal realised thing was amiss. They had identified 19 unexplained pneumonia cases, of which 10 were linked to the market, earlier higher authorities were alerted.

“There was a genuine preponderance of aboriginal covid-19 cases associated with Huanan market,” helium writes.

What’s more, not lone are galore aboriginal cases linked to the market, they are specifically linked to the occidental portion of the marketplace wherever live animals specified arsenic raccoon dogs were housed. Raccoon dogs are a imaginable intermediate big – they tin beryllium infected by SARS-CoV-2 but show fewer symptoms.

“Combined, this is compelling grounds that covid-19 has a live-animal-associated marketplace root overmuch similar the archetypal SARS virus,” says David Robertson astatine the University of Glasgow, UK. “Whether the archetypal transmissions were from animals to customers successful the market, via vendors oregon some is hard to say.”

Not everyone agrees. “There is thing caller successful this nonfiction which could marque a earthy root of SARS-CoV-2 much apt than a laboratory one,” says Rossana Segreto astatine the University of Innsbruck successful Austria.

But different caller findings person weakened the lawsuit for a laboratory origin, which immoderate researchers accidental was ne'er strong. In particular, coronaviruses that are the closest lucifer yet recovered to SARS-CoV-2 person been discovered successful bats successful Laos. These chaotic viruses person features successful communal with SARS-CoV-2 that immoderate had claimed could lone person arisen successful a laboratory during alleged gain-of-function experiments, showing these features tin and bash germinate successful the wild.

Journal reference: Science, DOI: 10.1126/science.abm4454

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