A critical new clue has recently surfaced in the multiyear hunt to determine the origin of COVID, which has killed at least 7 million people worldwide. Scientific researchers report there is evidence suggesting raccoon dogs in Wuhan’s wet market may have been infected with the novel coronavirus at the same time as the first human cases were detected clustered around the market in late 2019. The data from China, which Chinese authorities may have tried to hide from the world’s eyes, is some of the most compelling evidence to date that SARS-CoV-2 is of natural origin, rather than having been accidentally made in a laboratory before somehow escaping, as the so-called lab-leak theory postulates. Below are some answers to key questions about the revelation and what it means.
Where did the raccoon-dog data come from?
In January 2020, soon after the novel coronavirus first began sickening people in Wuhan, China, scientists from the Chinese Center for Disease Control and Prevention used swabs to collect samples from around the city’s Huanan Seafood Wholesale Market, where dozens of species of live animals, including wildlife, were also sold. A few weeks ago, genetic sequences from the samples, which included swabs from inside live-animal cages in the market, were briefly posted to — then removed from — an international genomic database used by scientists called GISAID. Before the sequences were taken down, however, a French scientist happened upon them and downloaded the data, then she and a team of other scientists began analyzing it.
Their analysis, published on March 20, has revealed that some of the samples containing SARS-CoV-2 material included large amounts of DNA and RNA belonging to raccoon dogs, a small animal in the fox family that was illegally traded at the market and has previously been found to harbor viruses which can be spread from animals to humans, including, in 2003, the COVID relative SARS-CoV-1. This suggests that raccoon dogs being sold at the market may have had COVID, and thus could have been spreading it to other animals and humans.
Since the news of the analysis, the World Health Organization has called on China to release the original data that Chinese researchers uploaded, then removed, from the GISAID database, as well as any other data which might help determine where SARS-CoV-2 came from. China, however, has repeatedly sought to discredit the idea that COVID originated — in any way — inside its borders.
Is this the smoking gun scientists have been looking for?
The presence of the raccoon-dog genetic material does not definitively prove that a raccoon dog at the market had — or gave the world — COVID. And even if a raccoon dog at the market had and spread COVID, it could have been infected by another source which also infected people at the market, including a human source.
The only smoking gun for animal spillover would be a COVID-positive sample swabbed from that animal, but there are no known samples directly taken from the animals that may have been in the market when the outbreak began, if there were ever any even collected in the first place before the animals were culled and market disinfected to help contain the first outbreak. But combined with other evidence, like that suggesting the market was the primary source of Wuhan’s first major outbreak, the sequence data strengthens the case for COVID having spilled over from wildlife to humans, which is what scientists have mostly suspected from the start.
As The Atlantic’s Katherine Wu explained in the first report about the new genetic-sequence analysis, it’s instead like “finding the DNA of an investigation’s main suspect at the scene of the crime.”
Does the raccoon-dog data disprove the lab-leak theory?
No. The lab-leak hypothesis — that SARS-CoV-2 was made in the Wuhan Institute of Virology, where researchers have studied bat coronaviruses genetically similar to COVID, before somehow escaping the facility and infecting the public — remains plausible. For instance, it’s possible the virus somehow escaped the lab and was somehow spread to people and animals at the Huanan Seafood Wholesale Market, which was about eight miles away, triggering an outbreak there which just happened to first produce more symptomatic confirmed cases than any other outbreak in the city. But unlike the natural-origin hypothesis, no evidence has emerged linking SARS-CoV-2 to the facility.
Will the lab-leak theory ever be proved or disproved?
That’s not clear, but don’t count on it. Since the lab-leak theory continues to become more popular as well as more politicized, coupled with the fact that China has hardly been transparent with its COVID data, to say the least, it’s difficult to imagine this will ever be a completely settled debate.
This post has been updated.