[ad_1]
reThe question of where exactly the starting point of the Covid 19 pandemic was and how the virus managed to leap from the animal kingdom to humans remains an open question. To answer them, the World Health Organization (WHO) plans to send an international team of researchers to China in January 2021. Every imaginable scenario must be examined.
According to a WHO working paper, the place where the emergence of a new epidemic is first perceived does not necessarily have to be the place where the outbreak began. There is some indication that the Sars-CoV-2 virus had already been transmitted from person to person for a time before it was discovered as a new pathogen.
The ten-member WHO team also includes a German scientist, microbiologist Fabian Leendertz of the Robert Koch Institute (RKI). The mission is not about finding the guilty party, but about understanding “what has happened to reduce future risks,” Leendertz said.
There have already been several virtual meetings with Chinese colleagues, and they have been “very productive.” About a year after the discovery of the first cases of novel coronavirus infections in China’s Wuhan region, WHO experts will be dispatched to China for five to six weeks.
Animal-to-human virus transmissions occurred every year, Leendertz says. It is simply “bad luck” that it has developed so “maliciously” in this case. It is an advantage for scientists’ work if they find “fresh leads,” but that is not absolutely necessary, explains Leendertz.
Even now there is a good chance of clarifying the early history of the Covid 19 pandemic. Leendertz notes that he recently observed how rubella passed from animals to humans 25,000 years ago.
In hindsight, scientists have found on the basis of unpublished reports that there were cases of Covid-19 in some countries prior to the official discovery in China, according to a WHO article. The virus could have spread for a while and could have been carried outside of China as well. In any case, the knowledge of timing is still very incomplete.
In this context, the WHO became the target of criticism in the summer of 2020. In a version of the chronology of the crown published by the WHO on April 27, 2020 it still said: “31. December 2019: Wuhan Municipal Health, China reports a cluster of pneumonia in Wuhan. A new coronavirus was subsequently identified. ”
An updated version of the WHO chronicle suggested that China did not report the first cases of corona on December 31, 2019, but later and not on its own account. Consequently, WHO first learned of the infections from its own office in China.
No one should expect “conclusive results” to be available immediately after the research team’s stay in January, Leendertz says. But he hopes there is at least a “concrete plan” for a second phase.
Most scientists assume that bats were the original hosts of the coronavirus. However, it is not clear which animal became the mediator in transmission to humans.
The researchers were able to show that the genome of the Sars-CoV-2 virus is 96 percent identical to that of a coronavirus called RaTG13 found in bats. This is an indication that this is the starting point of the pandemic.
The fact that the virus may not have circulated in human hosts for too long in early 2020 is proof of the great homogeneity of the pathogen’s genetic makeup. Initially, the Sars-CoV-2 virus genome found in several patients matched 99.98 percent, explains French virologist Étienne Decroly of the AFMB Institute in Marseille. Only recently have larger mutations and thus qualitatively new types of Sars-CoV-2 pathogens been discovered.
What remains a mystery, however, is that researchers have not yet been able to identify an intermediate host that could have carried the bat virus to humans. Furthermore, so far no viruses have been found whose genetic material lies between the genetic material of RaTG13 and Sars-CoV-2.
After all, they differ by four percent, so there should be intermediate steps. In any case, no case has ever been documented where a virus is transmitted directly from a bat to humans.
Étienne Decroly points out another problem. The bats in which RaTG13 was detected live in a cave about 1,500 kilometers from Wuhan. How could pathogens get past this route and in which intermediate host?
The genetic difference between Sars-CoV-1 (“Sars”) and Sars-CoV-2 is 21 percent. Therefore, it seems ruled out that Sars-CoV-2 could have arisen from Sars-CoV-1 through mutations.
So there are many questions waiting for the WHO research team. According to Leendertz, the team will try to go back on the time axis and determine if the first cases of infection had not occurred before December 2019. Another research focus is the Wuhan market, where exotic animals are sold live.
Leendertz is confident that one day they will find out what really happened. But this will not be “tomorrow”, it will take a certain amount of time.
Meanwhile, he hopes politicians will stay out of scientific studies “to the extent possible,” says the 48-year-old in the face of criticism of outgoing US President Donald Trump, who accused China of covering up and accused the WHO of submitting too strongly to the will of the leadership in Beijing.
And there is still a suspicion that the virus could have accidentally escaped from a research laboratory. However, so far there is no evidence for this.
“No hypothesis is excluded”
“Before an intermediate virus between RaTG13 and Sars-CoV-2 is discovered,” says Étienne Decroly, “the origin of Sars-CoV-2 will remain in the dark.” WHO states: The research project is open and iterative. No hypotheses are excluded from the beginning.
In addition to Fabian Leendertz, the WHO team includes: Thea Fisher (Denmark), John Watson (Great Britain), Marion Koopmans (Netherlands), Dominic Dwyer (Australia), Vladimir Dedkov (Russia), Hung Nguyen (Vietnam) , Peter Daszak (USA)), Farag El Moubasher (Qatar) and Ken Maeda (Japan).
