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How did bat coronavirus jump onto people? Scientists were looking for the answer to this question. They doubt that there is a direct connection between one and the other; they consider it more likely that host animal,
In the course of these searches, they first spoke of snakes, and more recently, of lizards, animals characteristic of Asia. However, these species were excluded due to the lack of correspondence in the genome of the coronavirus strains that were isolated from them.
Now a new report points to stray dogs – More specifically, for your gut – as a possible point of the current pandemic. This is evidenced by a study published this Tuesday by the University of Oxford in its journal. Molecular biology and evolution.
The author of the study is Shuhua Xia, a professor of biology at the University of Ottawa (Canada). He examined 1252 beta-coronavirus genome of various species that are currently stored in GenBank, the US National Institute of Health (NIH) genetic database.
“Our observations allowed us to formulate a new hypothesis about the origin and primary transmission of SARS-CoV-2,” Xia said.
“The ancestor of SARS-CoV-2 and its closest relative, bat coronavirus (BatCoV RaTG13), infected the intestines of canids (a family of mammals that includes dogs), whichThis probably caused the rapid evolution of the virus in dogs, and then jumped to people“He continues.
“This indicates, importance of monitoring ARVI type coronaviruses in stray dogs, in the fight against SARS-CoV-2, ”emphasizes the scientist. In particular, he suggests performing a rectal smear test on these animals to detect the presence of the virus.
Xia presents a scenario in which the coronavirus spread first from the murblinds to stray dogs that they ate bat meat, And that it infected his intestines.
According to the scientist, the animal host has had a “rapid evolution of the virus.” For Xia, the “most dangerous” is that it is a species that “carries SARS-CoV-2 but does not show clear signs of disease”. And he explains that zoonotic transmission should be very rare, otherwise several shoots, not local origin.
For Xia, the key is in the digestive system of mammals. Dogs often lick their anal and genital areas not only during mating, but also in other circumstances. This behavior will contribute to the transmission of the virus. digestive system of the respiratory system,
“In this context, it is important that bat coronavirus was isolated from a fecal smear. These observationsthis is consistent with the hypothesis that SARS-CoV-2 developed in mammalian intestines or intestinal tissue, “says the scientist.
Finally “jumped” on people. “The virus has successfully escaped antiviral protection mediated by ZAP (zinc finger). In other words, the virus has become secretive and dangerous to humans“Says Xia.
Also known receptor for the penetration of SARS-CoV-2 into the cell is an enzyme called ACE2. This enzyme is produced in human digestive systemat the highest levels in the small intestine and duodenum, with relatively low expression in the lungs. This suggests that the digestive systems of mammals are probably the main target infected with coronaviruses.
The author interprets that the ancestor of SARS-CoV-2 develops in the digestive system of mammals. And this is “confirmed once again” by a recent report indicating that a significant proportion of patients with COVID-19 also suffer digestive discomfort, “In fact, 48.5% reported digestive symptoms as the main complaint,” said Xia.
“People are part of nature, and contact with wild animals is inevitable, creating opportunities for zoonotic transmission,” he notes. “It is important to know what potential pathogens exist. If we know that the bat virus uses the X-receptor to enter the cell, and if the X-receptor in this bat is very similar to the human equivalent, then the virus can potentially penetrate our cells if it is given the opportunity, ”concludes he. scientist.
Is being consulted bugleDr. Esteban Fiore, Member of the Laboratory of Gene Therapy, Australian University of Translational Medicine Research Institute – Koniket, comments that the work ” new“I did not find a previous bibliography on this subject in SARS-Cov-2,” he says.
“In this arThis article is proposed as a possible hypothesis that the origin of SARS-CoV-2 may be in stray dogs“They argue that this could be the previous step in their evolution from their natural reservoir, which is bats, to a virus that can infect humans,” Fiore explains.
“You confirm that other strains of coronavirus isolated from bats and dogs have a high homology with SARS-CoV-2 in their genetic information and, more importantly, they have an adaptation that allows them evade the immune system host, “continues the Argentine expert.
“The author hypothesizes that CoV was first distributed from bats to stray dogs that fed on them. Later, in dogs, the virus acquired an adaptation to bypass the body’s defense mechanisms in the respiratory system, and became a pathogen. heavy for man. Thus, the dog is considered a possible “intermediate” animal. However, it is important to note that SARS-CoV-2 he was not isolated in dogsbut this is a hypothesis that is formulated from the above observations“says an Argentinean expert.
“The work seems serious and has a logical thread that supports the hypothesis,” Fiore continues. “Although the university in which the study is conducted and the scientific journal in which the work will be published are very prestigious, it is important to emphasize that they are testimony and studies supporting this hypothesis are still missing“he concludes.
