How does corona omicron mutate? Scientists favor the theory of fluctuation of the scales


date of publication :


08:05 2021-12-4

Opinion – Monitor

Some scientists speculate that the newly identified omicron may have evolved in an animal species, possibly rodents.This theory claims that an animal may have caught the SARS-Cove-2 virus, around the middle of 2020, according to a report published by Science. After accumulating several mutations in the animal, the modified coronavirus was ready to be transmitted to humans.

This chain of events can be described as reversible zoonotic diseases, in which the pathogen is transmitted from human to animal, followed by zoonotic disease, in which the pathogen is transmitted from animals to humans.

One of the main evidence supporting this theory is that Omicron diverged from other Covid-19 mutants a very long time ago, said Kristian Andersen, an immunologist at the Scripps Research Institute.

Compared to other theories about the origin of omicron, such as its evolution in an immunocompromised person or in a human population with poor virological surveillance, “this reverse zoonotic disease followed by a new zoonotic disease seems more likely to me, given the evidence available for the truly deep branch.” .which means that the early split from other coronavirus mutants, and then the mutations themselves, occurred because some of them are completely unusual,” Andersen said.

The omicron carries 7 mutations that would allow the mutant to infect rodents, such as mice and rats; Other troubling mutants, such as alpha, carry only some of these seven mutations, said Robert Gary, professor of microbiology and immunology at Tulane School of Medicine. Gary also said it remains unclear whether omicron appeared in an animal or a human host.

Omicron carries a large number of mutations not seen in any other versions of Covid-19, and some scientists consider this as possible evidence that it appeared in an animal host.

“It’s interesting, how insanely different it is. It makes me wonder if other species can become chronically infected,” said Mike Worubi, an evolutionary biologist at the University of Arizona, referring to the omicron genome. New mutant with many mutations. But at this point, Worubi suspects that Omicron evolved in an immunocompromised human, not an animal.

Science reports that this is one of the leading theories proposed by other experts. In this scenario, an immunocompromised person may contract COVID-19, but develop a chronic infection, in which they cannot rid their body of the virus; As it continued to reproduce, it picked up many mutations. Evidence suggests that the alpha mutant may have acquired mutations in this way, but this has yet to be confirmed for Omicron.

If it does not appear in any immunocompromised animal or person, Omicron may have first appeared in a community with poor viral surveillance, meaning it may have spread and developed unnoticed for more than a year.

Christian Drosten, a virologist at Charité University Hospital in Berlin, told Science: “I suppose this didn’t happen in South Africa, where a lot of the sequence happens, but somewhere else during the winter wave.”

For this to be true, the infected population must be so isolated, that the Omicron does not spread much beyond its ranks, said evolutionary biologist Andrew Rambo, from the University of Edinburgh. He added, “I am not sure that there is any place in the world isolated enough to transmit this type of virus for that length of time without appearing in different places.”

The Corona virus has caused the death of at least 5,233,111 people in the world since the World Health Organization office in China reported the emergence of the disease at the end of December 2019.

At least 263,616,200 people have been confirmed infected with the virus since its appearance. The vast majority of those infected recovered, although some continued to experience symptoms weeks or even months later.

The figures are based on daily reports issued by each country’s health authorities and exclude subsequent reviews by statistical agencies that indicate much higher death numbers.

And the World Health Organization, taking into account the high death rate directly or indirectly related to Covid-19, considers that the outcome of the epidemic may be two or three times greater than the officially announced outcome.

A large proportion of less serious cases or asymptomatic cases remain undetected despite the intensification of examinations in a large number of countries.


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