The new virus, known as COVID-19, has caused tens of thousands of infections and hundreds of deaths.
At a meeting in Cairo on Wednesday, Richard Brennan, a regional emergency director with the WHO, told reporters that there is “no evidence that this virus was produced in a laboratory, and certainly no evidence that it was produced as a biological weapon.”
Coronaviruses are primarily zoonotic, being hosted in animals, and only in rare cases infect humans. Some of the viruses then spread from person to person, as is the case for the new virus, which caused the COVID-19 disease.
“We expect that this new virus represents a mutation of coronaviruses that started in an animal,” Brennan said.
International experts have not confirmed the origin of the new virus, which emerged in Wuhan in December 2019. Bats are one animal suspected to have hosted the virus. If that’s the case, experts believe that bats spread the disease to another animal before it was spread to humans, according to the WHO official.
“We believe it’s a zoonosis. We don’t believe it’s been fabricated in any laboratory anywhere,” he added. “This is one of the rumors that we need to snuff out very, very early.”
Brennan’s comments came a day after Brett Giroir, the assistant secretary for health at the U.S. Department of Health and Human Services, told a conference in Washington that American officials “have no information whatsoever about this being a manufactured virus.”
The origins of the virus, are not clear, he said before adding there was “a lot more work that needs to be done.”
International health experts and officials in some countries have repeatedly said they don’t know how the virus started and some have noted China’s lack of transparency in sharing some information about the outbreak as well as the delay in transmitting information. China has also barred U.S. experts from traveling to the country, though it finally accepted a WHO team over the weekend.
Speculation has run rampant because of the unconfirmed origin, with some noting that Wuhan hosts a P4 laboratory, the Wuhan National Biosafety Laboratory, which studies infectious diseases.
Sen. Tom Cotton (R-Ark.) said this week that the most likely source of the virus is natural but that it’s also possible the lab either accidentally or deliberately released the disease.
“None of these are ‘theories’ and certainly not ‘conspiracy theories.’ They are hypotheses that ought to be studied in light of the evidence, if the Chinese Communist Party would provide it,” he said in a statement.
“We ought to be transparent with the American people about all this. Maybe some of these so-called experts think they know better. I don’t. And they really don’t either.”
Jack Phillips contributed to this report.