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The coronavirus that causes COVID-19 likely originated in animals and spread to humans, an international team of scientists from the World Health Organization said Tuesday. They also dismissed the idea that the virus was leaked from a laboratory in Wuhan, China.
The group has been working in the city for the past month to identify the origins of the COVID-19 pandemic and announced their findings during a virtual news briefing at the Hilton Wuhan Optics Valley hotel in Wuhan.
“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,” Peter Ben Embarek, the team lead and food safety and animal disease specialist for the WHO, said during the briefing.
“Did we improve our understanding? Did we add details to that story? Absolutely,” he added.
The virus likely transmitted from animals to humans, he told reporters, but more study is needed to be sure. The investigators aren’t sure which animal passed the virus to humans, but they are considering several species.
The team visited hospitals, labs, and markets, including the Huanan Seafood Market, the Wuhan Institute of Virology, and the Wuhan CDC lab. They didn’t find evidence of outbreaks in Wuhan before December 2019 but found widespread virus circulation outside of the Huanan Seafood Market during that time.
Researchers still hope to pinpoint the first cases of the pandemic to identify how the outbreak started, but the WHO has said it may take time, according to CNBC. It took more than a decade to identify the origins of SARS, for instance, and scientists still haven’t found the origins of Ebola from the 1970s.
Even still, the WHO investigation team dismissed the idea that a lab leak at the Wuhan Institute of Virology started the pandemic. They conducted “very diligent research” on the hypothesis and concluded that it isn’t likely, they told reporters on Tuesday.
“The laboratory incident hypothesis is extremely unlikely to explain the introduction of the virus into the human population,” Ben Embarek said. “Therefore, it is not in the hypotheses that we will suggest for future studies.”
Ongoing research will focus on how the virus circulated in animals before reaching humans. Bats and pangolins are candidates, though samples didn’t seem similar enough to the coronavirus, the investigation team said. Since minks and cats have contracted the virus during the pandemic, the research team is considering other animals as possible transmitters, but they don’t have strong conclusions so far.
The WHO has previously suggested that the coronavirus started in bats and then jumped to another species and then to humans, based on genetic sequencing. Many of the first human cases had links to the Huanan Seafood Market, and scientists thought the virus came from animals sold at the market.
However, China’s CDC has said that samples taken from the market suggest the virus spread there but didn’t start there. On Tuesday, the investigation team confirmed that an outbreak emerged at the market, but they couldn’t determine how the virus first arrived there.
WHO: “Virtual press conference on the WHO-convened Global Study of the Origins of SARS-CoV-2.”
CNBC: “WHO says Covid ‘most likely’ originated in animals and spread to humans, dismisses lab leak theory.”