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Scientists who the origins of the Covid-19 pandemic believe they have identified a possible source of transmission: China’s thriving wildlife trade.
The expected findings of experts convened by the World Health Organization and the Chinese government are expected to show parallels with the spawning in 2002 of severe acute respiratory syndrome, or SARS, a bat-borne coronavirus spread by vowels that killed 800 people. The path trodden by SARS-CoV-2 – as the new coronavirus is known – before it appeared in Central China in December 2019 remains a mystery, although researchers say it can be solved.
In Wuhan, where the first group of cases occurred, scientists involved in the hunt identified four hypotheses to explain the origin of the virus, including two that caused controversy, even though it was considered unlikely. The idea that the virus was introduced via contaminated food or packaging is being adopted in Beijing, while the Trump administration has said it may have been the result of a laboratory accident. But the most plausible theory, say experts involved in the mission, is about China’s trade in game for food, furs and traditional medicine, a business worth about 520 billion yuan ($ 80 billion) in 2016.
Read more: Where do we look for the origin of the Coronavirus?
Live animals susceptible to coronavirus infection were present at the Huanan food market in central Wuhan, the city where the first major Covid-19 outbreak was detected. It is possible that they acted as clues to the virus and transported it from bats – probably the primary source – to humans. Peter Daszak, a zoologist who was part of the joint research effort, who visited international experts at Wuhan earlier this year after months of stone-walling by the Chinese government.
“The most important conclusion from this stage of the work – and it is of course not over yet – is that exactly the same path on which SARS emerged was alive and well for the emergence of Covid,” said Daszak, who is also president of EcoHealth Alliance, a non-profit company in New York that works to prevent virus outbreaks around the world.
The scientific report, which is expected to be released this week delays due to political wrestling are unlikely to be decisive. More studies are planned, also outside China, with the decipherment of the creation story of Covid-19 that is essential to understand how it can best prevent its revival, and help prevent similar disasters in the future.
China makes it harder to solve the mystery of where Covid started
While the hunt for the origin of the virus has become political football for the world’s superpowers, Daszak says he thinks the scientific process will prevail. Important details about where the SARS-CoV-2 came from and how it originated will be discovered over the next few years, he said during a March 10 webinar organized by Chatham House.
SARS Distributed
Farmed and caught wild clinkers, a small, nocturnal mammal digested in China, have been blamed for spreading the SARS virus in a market in the southern province of Guangdong in 2003. Scientists later found that the infection originated in horseshoe bats, a natural reservoir of coronaviruses.
A civet at a market in KwaZulu-Natal in 2002.
Photographer: Richard A. Brooks / AFP / Getty Images
The two types probably collided in markets where live animals are caged pressure conditions, which could possibly cause the bat-borne virus adjust and reinforce before spilling over to people, initially under workers and those who handle the animals.
Scientists working on the original hunt say a similar scenario may have played out with Covid-19. A study of the first 99 patients treated in a hospital for infectious diseases in Wuhan found half are linked to the Huanan seafood market, which also to be heard live animals sold, some caught illegally in the wild and slaughtered in front of customers.
It is possible that the virus was introduced by an infected animal sold at the Huanan market or somewhere else in Wuhan, Dominic Dwyer, a microbiologist in Sydney, was part of the WTO meeting that went to the Chinese in February city traveled.
Yet there are still questions about the ultimate role of the market.
Tests after it closed in December 2019, no infected animals could show up. Infected surfaces were widespread, compatible with the virus introduced by infected humans or infected animal products. The first known Covid-19 patient, who put together the confusion, developed symptoms in the market four days before the earliest cases.
Visit Huanan and Wuhan’s other markets again (Video)
An analysis of SARS-CoV-2 samples collected in mid-December found subtle genetic differences between them. The variation indicates that the virus has been spreading in the community for weeks before doctors were warned about it by a handful of seriously ill patients with a mysterious viral pneumonia.
The original transmission of the coronavirus to humans was probably followed by a rapid adaptation of the virus, said Joel O. Wertheim, associate professor of medicine at the University of California, San Diego. It is possible that the virus has been transmitted several times and became extinct when infected individuals transmitted the virus to no one, Wertheim and colleagues said in an article published in the journal Science on March 18. Eventually, the virus infects someone who passed it on to several people, who also transmitted it to others, possibly in a super-spreading event.
The Huanan market may have been where it took place, Wertheim said in an interview. “The market was possibly the key to the virus infecting itself in humans.”
According to current evidence, the market is where SARS-CoV-2 is strengthened, and not necessarily its birthplace, Dwyer said.
‘Perfect place’
“When you visit the market, you realize that this is the perfect place to break out because it is crowded, lots of stalls, lots of animal products and ventilation and drainage is a bit suboptimal,” he said in an interview. “It’s not surprising that we exploded there.”
The WHO research team found evidence game farms in southern China have provided traders in the Huanan market, Daszak told US National Public Radio. It also found a route from southern provinces such as Yunnan – where the the coronavirus that was closest to SARS-CoV-2 was found in horseshoe bats in 2013 – to Wuhan, he said at the Chatham House webinar.
Members of the WTO team arrive at the Chinese Center for Disease Control and Prevention in Wuhan in February.
Photographer: Hector Retamal / AFP / Getty Images
“It provides a link and a way in which a virus can convincingly spread from wildlife to people or animals farmed in the region, and then somehow ship to a market,” Daszak said. ‘This is a very important clue. The beginning of an understanding of a path must be followed up fairly quickly. ‘
For decades, the Chinese government has promoted the farming of game to boost rural incomes. The practice has provided a very valuable alternative source of meat African swine fever originated in 2018. The deadly outbreak has led to an unprecedented shortage of pork, researchers at South China Agricultural University and the University of Glasgow have said. in a study released in February without a formal peer review. China usually consumes half of the world’s pork.
Squirrels, porcupines
While the shortage of pork consumed game, birds, snakes, bamboo rats, squirrels, porcupines and other non-domestic animals have been popular, especially in southern provinces, the researchers said.
They cite a 2004 survey by the China Wildlife Conservation Association which found that 46% of urban residents had game and 2.7% had ordinary consumers. A January 2017 survey found that 52% of the markets they surveyed were trade in game, while 40% of the restaurants provided wildlife dishes.
Many of the the trade presumably ended just over a year ago. After President Xi Jinping warned that wildlife consumption was a a huge risk to public health, the Standing Committee of the National People’s Congress decided on 24 February 2020 to extend the scope of China’s wildlife protection law to prohibits the consumption of almost all wild animals.
Amid international criticism of dealing with the early days of the pandemic, China’s official rhetoric focuses on doubts that the pathogen originated within its borders. But China targeted natural trade a year ago for a reason, Daszak told NPR.
“The reason for this was that in February 2020, they believed it was the most likely path” for the coronavirus to reach Wuhan, he said. “And when the WHO report appears, we believe it is also the most likely way to go.”