By Daniel Stolte, University Communications

Thursday

The Huanan Seafood Wholesale Market in Wuhan, China has become the most likely source of the COVID-19 outbreak, according to a new article by Michael Worobey of Arizona.
Wikipedia / China News Service

The Huanan Seafood Wholesale Market in Wuhan, China has become the most likely source of the COVID-19 outbreak, making an alternative explanation possible that the virus leaked from a laboratory in increasingly unlikely research, according to an article published in the journal Science by Michael Worobey, an expert on virus evolution at the University of Arizona.

By digging through health records and genomic and epidemiological data from the early days of COVID-19, Worobey pieced together a detailed picture of the first crucial events that escalated into the global pandemic. Through methodical analysis, he provides evidence that refutes a commonly held conjecture: that the Huanan wet market appeared to be the epicenter of the pandemic only due to a bias in the false market-centric case reports. seafood.

It is now clear that live mammals susceptible to coronaviruses, including raccoon dogs, were sold at Huanan Market and three other live animal markets in Wuhan just before the pandemic, Worobey reports in his article. Coronavirus-like viruses were found in raccoon dogs during the first SARS outbreak, which was facilitated by animal-human interactions in live animal markets in China.

Michael Worobey heads the Department of Ecology and Evolutionary Biology at the College of Sciences.

Michael Worobey
Beatriz Verdugo / UANews

Due to early public health attention to the Huanan market, it was not clear whether the preponderance of COVID-19 hospitalizations associated with the market truly reflected the source of the initial outbreak. Worobey set out to resolve several crucial events that took place in December 2019 and January 2020.

“The question I wanted to address was whether the apparent link between the early cases and the Huanan market was real or just a mirage, because that’s where people were looking for cases,” said Worobey, a professor in the department. Arizona Ecology and Evolutionary Biology.

“Let’s imagine the following scenario,” Worobey said. “Because the first SARS (Severe Acute Respiratory Syndrome) outbreak in 2002-2003 was associated with animals sold in wet markets, there was a system in place in which whenever a doctor saw a patient with pneumonia , he would ask him if he worked in a wet market, and if they did, this case would be recorded as something very interesting. But if a person had identical symptoms but answered no to this question, they would not be recorded as a case. “

In such a scenario, he explained, it would hypothetically be possible to end up with a city like Wuhan, with a population of 11 million, where 50 cases of early COVID infections would appear to be market-related, all the while, there could be 10,000 cases that go unnoticed in the rest of the city.

By specifying that it was the doctors, and not the epidemiologists, who discovered the first patients with COVID-19, Worobey shows that the cases with a history of exposure to the Huanan market could not have been “chosen” before that anyone has identified the market as an epidemiological risk. factor. Therefore, there was a true preponderance of early COVID-19 cases associated with the Huanan market.

Another key finding came when Worobey discovered a discrepancy in a joint report by Chinese health officials and the World Health Organization. According to the report, a patient unrelated to the market was considered the first known case of COVID, exhibiting symptoms on December 8, 2019.

However, this patient did not show symptoms of COVID-19 until a week later, on December 16, 2019, and this radically changes the image presented by the China-WHO report. According to Worobey’s analysis, the first known case is that of a saleswoman in the Huanan market.

“The December 8 case was used by supporters of the lab leaks to claim that the virus could not have appeared on the market since the first case was not exposed to it,” Worobey said. “Moreover, it has led them to claim that the pandemic started at the BSL4 facility at the Wuhan Institute of Virology, because this facility is close to where this person lived and shopped. But it is clear that this patient fell ill after the first cases were reported in Huanan, so it is clear that the virus was circulating in the community at that time. “

He added that since the market is the size of a football field in a city of 11 million people, it would be difficult to explain the pattern of early infections there if the pandemic had not triggered on the market when a virus has passed through a sold animal. to a person.

“It’s important to remember that because only about 7% of SARS-CoV-2 infections lead to hospitalization, the majority go unnoticed, which means we shouldn’t expect the first patients identified to be the first infected or linked to Huanan market, ”he said. “Supporters of the laboratory leak theory should explain what appears to be a crazy coincidence of cases gathering around the market.”

Worobey compared the combined evidence to a “flashing red arrow pointing to Huanan Market as by far the most likely origin site, with failure to halt sales of illegal wildlife in markets like Huanan. as a reason “.

“The way the COVID-19 pandemic has unfolded fundamentally appears to be a direct repeat of the original SARS outbreak,” he said.