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Ottawa / Vienna. Since the outbreak of Covid-19 disease in China in December, science has puzzled the origin of the Sars-CoV-2 coronavirus. The widely accepted thesis is that the virus coagulated in bats and reached human species through pangolins.
Bats are considered a reservoir of dangerous pathogens, but they do not get sick themselves. As a result, viruses are updated. If they affect us humans, our defense is overwhelmed. In order for bat viruses to spread to humans, they often need an intermediate host. However, the coronavirus in the pangolin differs more from that of humans. Reason enough for Xuhua Xia, from the Canadian University of Ottawa, to prove this thesis.
Xia and her colleagues have examined the genetic fingerprint of the corona virus in various animal species. They come to the take that the pandemic started in dog feces. “Our observations allow a new hypothesis for the first infection with Sars-CoV-2,” Xia is quoted in a report in the journal “Molecular Biology and Evolution”: “The earlier version of Sars-CoV-2 and the bat coronavirus. Related, the intestines of canine-like animals are infected, which could have led to the rapid evolution of the virus in wild dogs so that it can then spread to humans. “
Dog who lived in the 1960s
Xia studies the molecular signatures of viruses on different hosts. When a viral pathogen hijacks the host’s cells, the immune system’s guards battle it out. The intruder reacts with changes to its genome. The protective protein in mammalian cells is called ZAP. It bases its defense on two nucleotides called CpG. But the virus is recovering by destroying CpG. Based on analyzes of 1,252 genomes of the beta coronavirus, Xia reports that Sars-CoV-2 and the BatCoV RaTG13 variant were the most successful. “The BatCoV RaTG13 genome, which was taken from a bat in Yunnan in 2013 but was only sequenced after the outbreak in 2019, is the next phylogenetic relative to Sars-CoV-2, the sequences are 96 percent identical,” Xia said. . However, when he examined canine coronaviruses (CCoV), which cause highly contagious symptoms in dogs, he found that CpG values are very similar to those of Sars-CoV-2 and BatCoV RaTG13. In dogs, the virus also enters the cell through the same receptor, ACE-2, as in humans, which is also found in the intestine. Xia assumes that the two corona viruses in the bat and in humans are due to a corona virus in the dog that lived in the 1960s.(its T)
