WUHAN, China | After four weeks of mission in Wuhan, China, WHO experts were unable to unravel the origins of the COVID-19 pandemic and several questions remain unanswered.
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The World Health Organization (WHO) team believes that the coronavirus probably migrated from bats to an undetermined species before infecting humans.
She also deemed “highly unlikely” that COVID-19 comes from a high security laboratory in Wuhan (center), thus invalidating many theories in this direction.
Global pressure has weighed on the experts since the start of their investigation in China, which amounts to working “like mad people in the most politically charged environment”, according to one of them, Peter Daszak.
After a mission of almost a month, here are five unanswered questions regarding the origin of the coronavirus.
Animal origin?
Experts say tens of thousands of samples of wild, domestic and farm animals collected across the country have been analyzed, but none contained the Sars-CoV-2 virus.
Dutch virologist Marion Koopmans nevertheless explained that species very sensitive to the coronavirus (bamboo rat, badger, rabbit) were sold at the Huanan market in Wuhan, the site of one of the first clusters, which could be a starting point to go back the chain of contamination.
British zoologist Peter Daszak added that new viruses discovered in bats in Thailand and Cambodia “are shifting the cursor to Southeast Asia”. “I think we will find one day”, he judged, but “it could take time”.
Access to data?
Some worried about the difficulties of access to Chinese data for scientists, after Beijing had been accused of downplaying the severity of the epidemic when it started in Wuhan at the end of 2019.
Thea Kolsen Fischer, a Danish epidemiologist with the WHO, said the team had not received raw Chinese data, but had relied on analyzes from Chinese scientists. It is common for “aggregate data” to be provided to outsiders, she added.
WHO experts have assured that they have obtained access to all the sites and people they wanted.
The thesis of frozen foods?
Beijing has repeatedly mentioned the thesis that the coronavirus could have been imported to China via frozen food.
WHO Emergency Manager Mike Ryan believes there is “no evidence that food or the food chain is involved in the transmission” of COVID-19.
But in China, his team seems to have given this thesis some credit.
According to the head of the Chinese side of the mission, Liang Wannian, the coronavirus can travel great distances on the surface of cold produce, and analysis of samples from Huanan Market, which sold wild animals and frozen seafood has shown “widespread contamination” with COVID-19.
The head of the WHO team, Peter Ben Embarek, nevertheless warned that it is not yet known whether the coronavirus can be transmitted to humans through the cold chain.
From China or elsewhere?
Beijing urged the WHO to investigate a possible American origin of the epidemic. Chinese Foreign Ministry officials have raised theories about the coronavirus leak from a US military lab.
Pressed to escape international criticism, China has also released studies suggesting that COVID-19 emerged in late 2019 in Italy and other countries.
But Ms Koopmans ruled that the studies “do not provide any evidence of an earlier circulation” than December 2019 of the virus outside China, nevertheless adding that experts “should really look for evidence of previous circulation”.
And now ?
For Ms. Koopmans, farms supplying wildlife to Wuhan’s Huanan Market need further research.
In addition to taking more samples from wild animals in China and elsewhere, Mr. Ben Embarek suggested retesting samples using “new approaches” for blood work and looking for cases prior to December 2019 in Wuhan.
China, for its part, hopes that the next investigations will take place in another country.