Virus likely jumped to humans from bats through 'missing link', expert report says

An international expert mission, led by the World Health Organisation (WHO), to Wuhan has concluded that it was very likely that the novel coronavirus first passed to humans from a bat through an intermediary animal. This report rules out a laboratory leak incident.

The report from the international mission to Wuhan has been keenly anticipated ever since the expert team left China more than a month ago.

In the report -- a draft copy of which was obtained by AP and AFP news agencies, experts said that the intermediary host hypothesis was deemed "likely to very likely", while the theory that the virus escaped from a laboratory was seen as "extremely unlikely".

The experts and their Chinese counterparts had already made it clear during a lengthy press conference in Wuhan that they could not yet draw any firm conclusions. But they said they had worked to rank a number of hypotheses according to how likely they were.

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In the latest statement, experts said they believe that the SARS-CoV-2 virus that causes the Covid-19 disease originally came from bats.

One theory examined was that the virus jumped directly from bats to humans. The final report determined that this scenario was "possible to likely".

A more likely scenario, the report found, was that the virus had first jumped from bats to another animal, which in turn infected humans.

"Although the closest related viruses have been found in bats, the evolutionary distance between these bat viruses and SARS-CoV-2 is estimated to be several decades, suggesting a missing link," the report said.

"The scenario including introduction through an intermediary host was considered to be likely to very likely," it said, although it did not conclude which animal may have first allowed the virus to jump to humans.

The report meanwhile did not rule out transmission through frozen food -- Beijing's favoured theory -- since the virus appears to be able survive at freezing temperatures, saying that "introduction via cold/ food chain products is considered possible".

The report examined the idea of a lab leak from, for instance, the Wuhan Institute of Virology -- a theory promoted by former US president Donald Trump's administration.

It pointed to the fact that there was no record of any virus resembling SARS-CoV-2 in any laboratory before December 2019, and stressed high safety levels at the labs in Wuhan.

They, thus, said this theory seemed very unlikely.

(with inputs)