WUHAN, China (AP) – Coronavirus most likely appeared in humans after jumping off an animal, a team of international and Chinese scientists looking for the origin of COVID-19 said on Tuesday, saying an alternative theory that the virus leaked from a Chinese laboratory was unlikely.
A careful visit by experts from the World Health Organization to Wuhan – the Chinese city where the first cases of coronavirus were discovered – did not dramatically change the current understanding of the first days of the pandemic, said Peter Ben Embarek, leader of the WHO mission.
But he “added details to that story,” he told a news conference as the group concluded a four-week visit to the city.
And it allowed the Chinese-WHO joint team to further explore the theory of laboratory leaks – which former US President Donald Trump and officials in his administration proposed without evidence – and decided it was unlikely. The Wuhan Institute of Virology hosts several different virus samples, leading to allegations that it may have been the source of the initial outbreak, either intentionally or accidentally.
Embarek, a WHO expert on food safety and animal diseases, said experts now consider the possibility of such a leak so unlikely that it will not be suggested as a future avenue of study. But another member of the team, Danish scientist Thea Koelsen Fischer, told reporters that team members could not rule out the possibility of further investigations and new opportunities.
China had strongly rejected the possibility of a leak and promoted other theories. Chinese and foreign experts have analyzed several ideas about how the disease first reached humans, leading to a pandemic that has now killed more than 2.3 million people worldwide.
Embarek said the initial findings suggest that the most likely path the virus followed was from a bat to another animal and then to humans, adding that it would require further research.
The findings suggest that the laboratory incident hypothesis is extremely unlikely to explain the introduction of the virus into the human population, he said.
Asked why, Embarek said that accidental releases are extremely rare and that the team’s review of Wuhan Institute’s laboratory operations indicated that it would be difficult to get rid of it.
He also mentioned that there were no reports of this virus in any laboratory anywhere before the pandemic. Liang Wannian, the head of the Chinese side, also pointed out that, saying there is no sample in the Wuhan Institute.
The mission was meant to be an initial step in the process of understanding the origins of the virus, which scientists claimed could have been transmitted to humans through a wild animal, such as a pangolin rat or bamboo. Direct transmission from bats to humans or through trade in frozen foods are also possibilities, Embarek said.
The visit of the WHO team is politically sensitive for Beijing, which is worried that it will be accused of alleged mistakes in its early response to the outbreak. An AP investigation found that the Chinese government has put limits on research on the outbreak and ordered scientists not to talk to reporters.
However, a member of the WHO team, British zoologist Peter Daszak, told The Associated Press last week that they enjoyed a higher level of openness than they had anticipated and that they were given full access to all required sites and staff.
Koelsen Fischer said that he did not get to see the raw data and that he had to rely on an analysis of the data that was presented to him. But he said this would be true in most countries.
U.S. State Department spokesman Ned Price said the United States is looking forward to seeing the report and data behind the WHO investigation.
The team – which includes experts from 10 countries who arrived on January 14 – visited Huanan Seafood Market, the site of an early group of cases in late 2019.
Marion Koopmans, a Dutch virologist on the team, said some animals on the market were susceptible or suspected of being susceptible to the virus, including rabbits and bamboo rats. And some could be tracked at farms or traders in the regions that host bats that carry the closest virus related to the one that causes COVID-19.
She said the next step would be to look more closely at the farms.
Liang, the head of the Chinese team, said the virus appears to have spread to other parts of the city, other than the market, so it is possible the virus may have spread elsewhere.
The team found no evidence that the disease was spreading earlier than the initial outbreak in the second half of December 2019.
“We have not been able to fully do the research, but there is no indication that there are clusters before what we saw happening in late December in Wuhan,” Liang said.
The WHO team’s visit took months to negotiate. China agreed to this only amid international pressure at the WHO World Health Assembly meeting in May, and Beijing continued to resist calls for a strictly independent inquiry.
While China has withstood some localized recurrence of the infection since controlling the outbreak last year, life in Wuhan has largely returned to normal.
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Associated Press writers Ken Moritsugu in Beijing and Jan M. Olsen in Copenhagen, Denmark, contributed to this report.