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“The punishments for criminals can be harsh,” says Zhou Zhaomin, a policy expert on China’s wildlife trade at China West Normal University in Nanchong. Trade in protected species is punishable by up to 15 years in prison, and smuggling them to or from China in sufficient numbers can result in life imprisonment.

But enforcement of the law was poor. Several researchers told the MIT Technology Review that the prevalence of the illegal wildlife trade in China is “an open secret.”

Indeed, Zhou and colleagues questionnaire It found that between 2017 and 2019, four markets in Wuhan, including Huanan, sold a total of approximately 48,000 wild animals of 38 species, almost all of which were live, caged and stacked in cramped, unhygienic conditions perfect for virus transmission. Animals – either wild-caught or farm-raised non-domesticated species – include species susceptible to both SARS-CoV-1 and SARS-CoV-2, such as musk, mink, badger and raccoon dogs.

This study, published in June, Scientific Reportsfound that the entire wildlife trade the researchers investigated was illegal. Many vendors sold protected species; none have issued the necessary certificates of origin or disease-free nature of the animals.

While this means that as soon as Huanan is involved in early covid-19 cases, it likely means that sellers who illegally sell live mammals will flee to avoid jail time, while law enforcement is unlikely to admit that such activity exists. Hanage of Harvard says it’s not surprising that Chinese officials found no leads on the sale of livestock in the Huanan market.

Restrictions on wildlife trade were minimal in the wake of SARS, which gave scientists virtually unlimited access to animals and traders in Guangdong’s wet markets – but even that wasn’t enough to help them pinpoint the source of SARS. While it quickly settles on viruses in civet cats, badgers and raccoon dogs, More than 99% identical to SARS-CoV-1, subsequent investigations did not reveal widespread circulation of the virus in either wild or farm conditions. The dominant view is that civets caught virus during trade, possibly from bats traded simultaneously.

Now, 18 years later, the situation is strikingly similar. there seems to be no widespread circulation of SARS-CoV-2 in animals. Of the 80,000 samples tested by the Chinese team of the World Health Organization mission to investigate the origin of the pandemic, none of which contained the virus, including prime suspects such as pangolins, civets, badgers and bamboo rats.

However, many scientists still weigh in on the theory that wet markets play a critical role in triggering covid-19. While all eyes are on Yunnan and other parts of Southeast Asia as the most likely outlets for the pandemic, Hanage says it’s “not insane” to suggest that Wuhan’s Hubei province could be the place where SARS-CoV-2 naturally emerged.

Indeed, scientists at the Wuhan Institute of Virology SARS-like coronaviruses in bats in Hubei. Although they have not systematically tested livestock across the province for coronavirus infection, little known study In their post-SARS study, they found that all seven civet cats they tested on a state farm in 2004 were infected with their SARS-CoV-1 relatives. Several research teams in China and the US are trying to understand where the animals contracted the virus, whether coronavirus infection among civets is more common than previously thought, and what implications this might have on our understanding of the origins of covid-19.

continuous spread

However, without evidence of an animal infected with a coronavirus that is more than 99% identical to SARS-CoV-2, some scientists continued to argue against natural origins.

One such critic is Alina Chan, a molecular biologist at the Broad Institute of MIT and Harvard (this publication is owned by MIT but is editorially independent of it). The central question, said one Latest webinar hosted by Science magazineis how the virus reached Wuhan from caves more than a thousand miles away in China or other parts of Southeast Asia. “There is a very strong channel of scientists in Wuhan, they land in these places. [knew] “They find SARS viruses and bring them thousands of kilometers to the city of Wuhan,” he said. However, there is no evidence of such routes for the wildlife trade, he adds.

Such a lack of clarity is also plaguing the origins of SARS, says Linfa Wang, director of Duke-National University Singapore’s emerging infectious diseases program. The cave where SARS-CoV-1’s closest bat relative is located is about 1,000 miles from the Guangdong market, where the first SARS cases arose – similar to the distance between Wuhan and where one of SARS-CoV’s closest bat relatives lives. -2 discovered.

And it’s becoming increasingly clear that people in close contact with wildlife are infected with coronavirus much more often than previously thought.

“[Huanan] It’s much more likely than other scenarios based on what we currently know.”

Michael Worobey

Studies show that up to 4% people living close to bats and working closely with wildlife Deadly animal-borne viruses, including coronaviruses, have been infected in southern China. A Laos and French team discovered The closest relatives of SARS-CoV-2, found One in five bat handlers in Laos had antibodies to these coronaviruses.

The researchers say that many of these spreading infections disappeared of their own accord. In a study published in the journal Science in April, Worobey and colleagues show in computer simulation that an urban environment is critical for the spread of SARS-CoV-2 to trigger large epidemics – without which, it would perish very quickly.

A wildlife trader exposed to a SARS-CoV-2 ancestor (from bats or another animal species) is “hundreds or even thousands of times more likely” to transmit the virus to Huanan. Wang says he returned to Wuhan with the pathogen to collect samples from the bats, and then brought it to Huanan.

Worobey agrees. Based on a lot of evidence, he is now convinced not only that the pandemic’s connection to the Huanan market is real, but that it is also where a SARS-CoV-2 ancestor jumped from an animal to humans. “This is much more likely than other scenarios based on what we know now,” he says.

Initial results from the ongoing work of his group and others will help strengthen the situation further, he adds: “They all point in the same direction.”

Reporting for this article was supported by a grant from the Pulitzer Center.