The team reported that the most likely pathway for the virus to get a grip on humans was a crossover from an intermediary species, but there is no conclusive evidence so far as to what animal that might have been.
In January, after two weeks of quarantine and many negotiations over the arrangements of the trip, the World Health Organization’s (WHO) international team of scientists began their investigation in Wuhan to try and uncover the origin of the COVID-19 virus.
Over the past two weeks, the team has visited the Wuhan Institute of Virology, the Wuhan Center for Disease Control (CDC), the Huanan Seafood Market as well as various other laboratories, hospitals and markets.
The Wuhan Institute of Virology came under fire last year after cables surfaced in April from the United States Department of State suggesting that biosecurity at the institute was a potential threat. The US national intelligence director’s office issued a clarification, dispelling some of the more fringe theories that the virus was intended to be used as a bioweapon, but it did not rule out that lab contact could have been the inciting incident.
But the WHO investigation team has largely dispelled that theory after a news conference on Tuesday.
“The laboratory incident hypothesis is extremely unlikely to explain the introduction of the virus into the human population,” said Dr. Peter Ben Embarek, the chairman of the team of investigators and the food safety and animal disease specialist at the WHO. He added, “[it] is not in the hypotheses that we will suggest for future studies.”
The team also said there was no evidence that any major outbreaks inside or outside of Wuhan happened before December 2019, but that there was evidence of increased spread of the virus outside of the Huanan Seafood Market in that month.
The team reported that the most likely pathway for the virus to get a grip on humans was a crossover from an intermediary species, but there is no conclusive evidence so far as to what animal that might have been.
Bats have been a prime suspect in this hunt for the animal origin. In an interview with the Scientific American last June, Wuhan virus expert Dr. Shi Zhengli, dubbed Wuhan’s “Bat Woman” for her extensive research with the animal, recalled fearing that the virus could have come from her lab.
But this is not supported by the WHO investigation, which reported that samples from bats and pangolins were found to be insufficient in terms of similarities to the version of the virus affecting humans. Bats and pangolins remain candidates for the animal scientists are looking for, but there is no concrete evidence thus far.
Seafood markets, such as the Huanan Seafood Market in Wuhan, were initially thought to be where the virus had originated due to the variety of wild animals being sold there. This theory has been altered as well though, with China’s CDC since reporting after taking samples that, while the markets were likely a place where the virus spread rapidly, it is unlikely to be where the virus actually originated.
There has been some concern that the WHO investigation in China could be limited in its scope due to Chinese pressure and influence over what the team will be able to research during their time in Wuhan. China has not published much on its internal research into the virus’ origins.
The WHO has been clear that even if an answer is not discovered during the investigation, an investigation still will have been important to fill in the gaps and clarify what happened.
“In terms of understanding what happened in the early days of December 2019, did we change dramatically the picture we had beforehand? I don’t think so,” said Dr. Ben Embarek. “Did we improve our understanding? Did we add details to that story? Absolutely.”
The search for the origin could now shift to Southeast Asia where the investigation would look at “cold chain” transmission, said Dr. Peter Daszak, a member of the investigative team.
“China is a very big place and Southeast Asia is a very big place,” he told the BBC. “The supply chains to the Huanan seafood market were extensive, they were coming in from other countries, they were coming in from various parts of China, so to really trace that back it’s going to take some work.”
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