How did the new Sars-CoV-2 virus get from bat to human? The answer is extremely important for scientists. Among other things, it explains why the virus is so well adapted to humans. Researchers from Canada have now identified a new possible intermediate host: stray dogs.
–
Many animals, from snakes to pangolines, have so far been accepted as a missing link in the chain. But the viruses isolated from these species deviate too much from SARS-CoV-2. Xuhua Xia, professor of biology at the University of Ottawa, followed the traces of the new corona virus across several species. And his thesis is: stray dogs – especially dog intestines – can be the origin of the current corona pandemic. Dogs that ate bats and whose legacy we came into contact with. Which is not that difficult, according to Xia, considering where dogs lick each other.
–
How does he get on the dogs?
When viruses enter an organism, it defends itself. And these “battle tracks” can be demonstrated later in the virus or in the way it changes. And that’s exactly what Professor Xia examined. He discovered that only dog corona viruses (CCoVs) had caused the same response in the viruses as in the case of the new Sars-CoV-2 and the original BatCoV RaTG13 bat virus. This change made it easier for Sars-CoV-2 to deceive human immune defenses. Earlier studies had shown that the virus is very well adapted to humans.
Xia’s research confirms this and also gives a strong indication of why Sars-CoV-2 can dock in the gastrointestinal tract in humans. It is due to ACE2 – a receptor that mainly exists in the human digestive system and to which the virus is optimally adapted. “The interpretation is confirmed by a recent report that a high proportion of Covid-19 patients also suffer from indigestion,” said Xia. “In fact, 48.5 percent showed digestive symptoms as the main complaint.”
–
You could have seen the danger
“In this context, it is unfortunate that BatCoV RaTG13 was not sequenced in 2013,” Xia continued. The bat virus, “is the closest phylogenetic relative of Sars-CoV-2 and has a sequence similarity of 96 percent”. As its name suggests, it was found in the excrement of a bat in the Chinese province of Yunnan in 2013. But it wasn’t until the end of 2019 that it was examined at the Wuhan Institute of Virology and discovered its compliance with the new virus, which was spreading wildly in the city. If this genetic examination had taken place earlier, according to Xia, the virologists would have noticed which survival strategy the virus has and what danger it poses to humans.
–
– .
