A member of the World Health Organization (WHO) team that recently spent time in China investigating the origins of the coronavirus pandemic says they've worked out where it probably came from.
Peter Daszak, a British expert on zoonotic diseases - those which leap from animals to humans - says the SARS-CoV-2 virus, which causes COVID-19, likely originated in southern China's wildlife farms.
"They take exotic animals, like civets, porcupines, pangolins, raccoon dogs and bamboo rats, and they breed them in captivity," Dr Daszak told US public broadcaster NPR.
And China appears to have figured that out early in the pandemic, abruptly shutting down the lucrative farms on February 24 as the outbreak there was being brought under control.
The farms supply sellers at the Huanan Seafood Wholesale Market in Wuhan, which was the epicentre of the first detected outbreak of COVID-19 in late 2019, the WHO investigation found. COVID-19 has since gone on to kill at least 2.7 million people worldwide.
The Huanan market was shut on December 31, 2019 - the same day China advised the WHO of the mystery outbreak of disease.
Many of the farms are in Yunnan, where scientists have found other coronaviruses genetically similar to SARS-CoV-2 - some almost identical, just lacking the key spike protein which makes the COVID-19 virus so infectious to humans.
Until the outbreak in Wuhan, authorities had promoted wildlife farms as a way for rural Chinese to make good money - they employed millions of people and generated tens of billions of dollars.
"What China did then was very important," said Dr Daszak. "They put out a declaration saying that they were going to stop the farming of wildlife for food... They sent out instructions to the farmers about how to safely dispose of the animals - to bury, kill or burn them - in a way that didn't spread disease."
SARS-CoV-2 was detected in live animals at the market in Wuhan, strengthening the link to the wildlife farms.
"China closes that pathway down for a reason," Dr Daszak told NPR. "The reason was, back in February 2020, they believed this was the most likely pathway [for the coronavirus to spread to Wuhan]. And when the WHO report comes out... we believe it's the most likely pathway too."
The present hypothesis is the virus developed in a bat, like the SARS virus nearly 20 years ago, then made the jump to humans, perhaps via another animal such as a pangolin. There have been calls from experts to cut back on industrial-scale animal farming, saying it's the primary cause of new diseases in humans.
The US under former President Donald Trump alleged there was evidence the virus was leaked from a virology lab in Wuhan, not far from the market. Scientists have rubbished this theory. To this day, Trump continues to call it the "China virus".
The WHO's policy nowadays is not to name viruses or diseases after places, as it can result in stigmatisation. For example, the 'Spanish' flu was actually first detected in the United States.
The WHO's report is expected to be released in the next couple of weeks.