Without always knowing its precise origin, we know that the SARS-CoV-2 coronavirus, the virus that caused the COVID-19 pandemic, is of zoonotic origin. This means that the virus has passed, by mutating, from a non-human animal to humans. Much research has cited bats as the original hosts of many SARS-like viruses, and bats are known to tolerate this type of virus without developing extreme symptoms. However, we are far from having identified all the animals that have developed this type of coronavirus tolerance mechanisms. Knowing the possible reservoirs of the virus is however essential for the surveillance of the epidemic.
This evolutionary analysis in different species of mammals, ACE2 receptors,
used by SARS viruses to penetrate into mammalian cells, thus reveals that rodents, in particular, have a greater diversity of amino acid sequences at the “ACE2” binding sites used by SARS- CoV-2 to bind to the host cell, suggesting an accelerated rate of evolution at these sites.
Overall, these results suggest that some rodent species have likely been exposed to repeated SARS-like coronavirus infections over a very long period of evolution. With these repeated exposures, the animals could have acquired thus a certain form of resistance to coronaviruses, explain these virologists.
“This raises the exciting possibility that certain types of modern rodents could be asymptomatic carriers of the SARS-like coronavirus”. To be continued …