Last week, a team of international researchers shared with the world a discovery possibly linking the origins of the COVID-19 pandemic to a breed of animal in a Wuhan, China wet market: specifically, a raccoon dog.
French virologist Florence Débarre of the French National Centre for Scientific Research spotted the information by chance while scouring a worldwide database, and shared it with a group of scientists based outside of China looking into the origins of the coronavirus.
The genetic sequences were uploaded to the world’s biggest public virus database in late January, but have since been removed.
According to the World Health Organization, genetic sequencing data showed that some of the samples taken at the Huanan Seafood Wholesale Market, which were known to be positive for the coronavirus, also contained genetic material from raccoon dogs, indicating the animals may have been infected by the virus, according to the scientists.
“There’s a good chance that the animals that deposited that DNA also deposited the virus,” said Stephen Goldstein, a virologist at the University of Utah who was involved in analyzing the data. “If you were to go and do environmental sampling in the aftermath of a zoonotic spillover event, this is basically exactly what you would expect to find.”
And while the connection signals good things in terms of getting closer to COVID-19’s origins, a lot of people were taken aback by the name of the animal. So what, exactly, is a raccoon dog?
Raccoon dogs: What you need to know
Physically, raccoon dogs look pretty much how their name implies — they resemble a small-to-medium size dog with a raccoon head. They’re small, fluffy and many have stout, rotund bodies.
Despite their name, however, raccoon dogs (Nyctereutes procyonoides) are most closely related to foxes. The species now linked to the COVID-19 outbreak is known as the common raccoon dog, which is different from its relative, the Japanese raccoon dog.
Raccoon dogs of both species originate in East Asia and have an average weight of 16 pounds, making them of little danger to humans. Fun facts: they are monogamous, have curved claws and go into a state of light hibernation in the winter.
They are also susceptible to SARS-CoV-2, and some have previously tested positive for the coronavirus. They have also been found to be able to pass on the disease. So while there’s still no solid proof that they are responsible for the virus outbreak in the Wuhan market, it does prove that the market was, indeed, selling animals that can carry the virus.
Raccoon dogs are omnivores and prefer to live in forests or areas of dense vegetation or that border water. And while they previously made their home in parts of China, Korea and Japan, breeding from the fur farming industry resulted in thousands being introduced to the Soviet Union in the 1920s.
Today, they are considered a widespread invasive species in western and northern Europe, and a European Union report on invasive species “of concern” declared it “one of the most successful alien carnivores in Europe.”
And while many North Americans might not be able to conjure up a real-life image of a raccoon dog from the top of their heads, chances are they’ve come across a depiction of one stemming from Japanese folklore. Known as “tanuki” in Japanese, in mythical settings raccoon dogs are shape-shifters that can bring good financial luck.
In Japanese animation, cartoons and likenesses, they’re often drawn with large scrotums that they can manipulate into useful objects like fishing nets, umbrellas and parachutes.
Raccoon dogs and their connection to viruses
As mentioned earlier, raccoon dogs have long been raised, bred and hunted for their fur, which is likely why they would have been sold at the Wuhan market.
As reported by Slate, millions are killed in China every year and a large portion of their pelts are bought by the U.S. In order to supply the global market for raccoon dog fur, the animals are often raised in crowded facilities from small cages, which is a recipe for the spread of disease.
A 2004 report from The Lancet says that raccoon dogs and related animals sold for food at a wet market in China in 2003 were found to carry a virus very similar to the SARS virus that was circulating in humans at the time. Officials at the time ordered the slaughter of 10,000 animals set to be sold at such markets, after alarms of another outbreak were sounded when a man tested positive for a novel strain of the SARS virus.
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A study conducted last year found that samples taken from 2,000 animals of 18 different species across China found that animals known to be eaten by humans, including raccoon dogs, carried 102 different viruses from 13 viral families.
Specifically, the study found that raccoon dogs carried four canine coronaviruses that were genetically similar to those found in humans. They also carried enteric viruses, or viruses that are transmitted when infected fecal matter enters the mouth or nose.
Are we closer to determining COVID-19’s origins?
The answer is yes… and no.
Late last week the World Health Organization (WHO) called on China to release the data that was taken down. Researchers say having the data will allow them to further analyze what was happening in the Huanan market in 2020.
“The big issue right now is that this data exists and that it is not readily available to the international community,” Maria Van Kerkhove, the WHO’s COVID-19 technical lead, told CNBC.
“This is first and foremost absolutely critical, not to mention that it should have been made available years earlier, but that data needs to be made accessible to individuals who can access it, who can analyze it and who can discuss it with each other,” she said of the importance of the molecular data, which was collected from swabs of the market’s floors, walls, cages and carts starting in January 2020.
Van Kerkhove told the outlet that the small amount of data they have right now doesn’t give a conclusive answer into the pandemic’s beginnings, “but it does provide more clues.”
“These data could have — and should have — been shared three years ago,” said Tedros Adhanom Ghebreyesus, WHO’s director general. The missing evidence now “needs to be shared with the international community immediately,” he told the New York Times.
And while raccoon dogs now fall within the realm of possibility of being among the first to be infected with SARS-CoV-2, there still remain many competing theories as to the virus’s origins — including theories that the virus originated in a Chinese government-controlled lab – which researchers continue to investigate.
Until China reuploads its data, Van Kerkhove told CNBC, the WHO “won’t be able to remove different hypotheses.”
University of Saskatchewan virologist Angela Rasmussen, who was involved with the data analysis, said it’s important to stress that the data does not definitively prove a raccoon dog was infected with the coronavirus.
“We just have evidence that the animals were in the same part of the market where we know there was virus,” she said.
The evidence does make it “more likely that an animal contributed the viral sequences that were in there,” Rasmussen added.
Arturo Casadevall, an immunologist at the Johns Hopkins Bloomberg School of Public Health, told the New York Times the data adds to the evidence of a natural spillover event.
“I would say it strengthens the zoonotic idea, that is, the idea that it came from an animal at the market,” he said.
After a weeks-long visit to China to study the pandemic’s origins, WHO released a report in 2021 concluding that COVID-19 most probably jumped into humans from animals, dismissing the possibility of a lab origin as “extremely unlikely.”
But the UN health agency backtracked the following year, saying “key pieces of data” were still missing.
In February, the Wall Street Journal reported that the U.S. Department of Energy had assessed “with low confidence” that the virus had leaked from a lab. But others in the U.S. intelligence community disagree, believing it more likely it first came from animals.
Experts say the true origin of the pandemic may not be known for many years — if ever.
— With files from The Associated Press