Controversy over the origin of the virus flares up again

Maria Van Kerkhove, an American epidemiologist at the World Health Organization (WHO), recently declared in the midst of renewed debate on the issue: “We cannot say definitively how the epidemic began.”

The scientific world mostly estimates that the epidemic began in early 2020 because a wild animal had transmitted the virus to humans months earlier, possibly at Huanan Market, in the Chinese city of Wuhan.

However, some researchers defend the hypothesis of a leak from a laboratory of a scientific institute in the same city.

China strongly rejects this theory, but also denies that the Huanan market houses animals that are vulnerable to transmitting the virus.

The controversy was revived in February after the head of the FBI confirmed this laboratory leak theory as “highly probable.”

Although it caused a huge media frenzy, it did not have much influence on the majority scientific opinion.

“These proposals do not appear to be based on new elements and [la teoría de la fuga] British scientist Alice Hughes, a biodiversity specialist, told Science Media that she remains less convincing in both hypotheses.

raccoon dog

Weeks later, advocates for natural transmission appealed to the media feature after a study analyzed samples collected at the beginning of 2020 in a Wuhan market.

Many American media, in particular The New York Times, reported on this work even before it was published on the Internet and presented it as a breakthrough in support of this thesis.

After the Huanan Market was closed in early 2020, many samples were taken by the Chinese authorities at the site. Scientists led by Frenchwoman Florence Debar worked on the basis of this data.

In them they find the DNA and RNA of many wild mammals, which makes it possible to establish their presence on the market before its closure.

The case of a raccoon dog stands out. This animal, which belongs to the canine family but looks like a raccoon, could be infected with the coronavirus and may serve as an infection link between bats and humans.

However, this work, which has not been published in a scientific journal, does not prove that the raccoon dog is the origin of the epidemic, nor does it allow us to definitively assert that these animals are infected because the samples were not taken directly from them.

Inaccessible data

However, this theory seems plausible given that in some markets, the DNA of these animals was very present with the virus, and on the other hand, no traces of the human genome were found.

However, even if they were introduced to the infection, it is impossible to determine whether they transmitted the virus to a human or whether transmission was reversed.

The study constitutes “a new piece of the puzzle supporting a link between the Wuhan animal market and the origin of the epidemic,” but it is “not definitive proof,” said virologist Connor Bamford of Queen’s University Belfast.

For him, it will be necessary to obtain samples older, from the end of 2019 when the virus appeared without making noise, and to take them directly from these animals.

But this is a major hurdle in investigating the origin of the virus: it is almost impossible to access the original data. Even the data that DeBarre’s team worked with is no longer available.

It was initially available on a platform for researchers, Gisaid, but was removed at the request of Chinese scholars who posted it online.

“We have very crucial data that allows us to clarify the beginning of the epidemic, but we cannot share it because it is not ours,” this researcher laments to AFP.

“The more people study them, the more information we’ll be able to extract,” he says.