WHO experts have found few clear answers about the origin of coronavirus, but many clues during visits to Wuhan.
A long-awaited report on the origin of the coronavirus has been released on Tuesday.
It shows that the virus probably originated from a special bat and that it was transmitted to humans via another animal.
This is what Thea Kølsen Fischer, who is a professor of public health, viral infections and viral epidemics at the University of Copenhagen, says.
She is among the experts who, in connection with a mission for the World Health Organization (WHO), have been in Wuhan, China, to investigate the origin of covid-19.
– The basic hypothesis based on the preliminary studies here is that the virus has bats of the type horseshoe bats as a host. And it’s the same type of bat that hosted the first coronavirus that caused a major epidemic in the world in 2003.
– The hypothesis is that a bat has infected an intermediate host that has not yet been identified. The intermediate host is an animal species. But there are many animal species that have been shown to be susceptible to the coronavirus, she says.
She explains that the bat has infected another animal, which has then passed the infection on to humans.
According to the report, the intermediate host can be, for example, mink, rabbits or shellfish. But it needs to be investigated further.
– We do not think it has gone directly from bats to humans, because we have a virus that is fully adapted to humans, as it triggers the epidemic. And it typically requires that the virus has changed into an intermediate host.
– The virus found in bats is 96.2 percent similar to what we find in humans. That difference indicates that there is still an unidentified intermediate host, says Thea Kølsen Fischer.
The WHO mission visited Wuhan in January to investigate the origin of covid-19, as it was here that the first major outbreak occurred. However, based on the preliminary studies, it can not be established that the virus originated in Wuhan in particular.
– But we can say, based on the preliminary studies, that the first major epidemic of covid-19 took place in Wuhan in December 2019, says Thea Kølsen Fischer.
The WHO mission has examined four overarching hypotheses for origin. Including whether the coronavirus could have originated in a laboratory, as, among others, former US President Donald Trump has claimed.
– It has previously been seen that viruses can cause human infection via laboratory leaks. So it obviously needed to be investigated.
– But the preliminary conclusions based on the studies we have done in Wuhan do not suggest that this is the way the virus is introduced to humans. But that cannot be definitively ruled out, she says.
In general, it is sparse what can be definitively concluded on the basis of the mission in Wuhan. This is the first step in an “expected long process”.
– We stand with the end of a twine key in our hand in front of a wall. On the other side of the wall is the yarn key, but none of us know how big that yarn key is. But we have the end.
– Now, during the next steps in the research process, we will go in depth with many of these clues that the first studies have generated, says Thea Kølsen Fischer.
/ ritzau /