Omicron Variant Likely Has Mouse Origin & What It Means For Us

Chinese scientists claim that there is evidence to support that Omicron’s DNA can be linked to a mouse.

Chinese scientists claim that there is evidence to support that Omicron’s DNA can be linked to a mouse.

THE Omicron variant may have evolved within mice and jumped back into humans, according to a study published in the Journal of Genetics and Genomics.

Chinese scientists claim that there is evidence to support that Omicron’s DNA can be linked to a mouse.

When the Omicron variant first got detected in South Africa on November 24, 2021, the build-up of mutations, some of which resist vaccines, raised alarm bells among scientists as to whether it originated in humans or other mammals as many of these mutations had not been seen before
earlier in other variants.

The study published by the team from the Chinese Academy of Sciences, argues that these mutations differ from the viruses that evolved in human patients.

The findings in the study also point out the resemblance of these mutations with the mutations associated with virus evolution in mouse cells. Furthermore, the mutations show that the virus has adapted to infecting mouse cells.

The study suggests that the virus may have hopped over to mice from humans where it accumulated these unusual mutations before jumping back into humans, indicating an inter-species transmission.

“Our results suggest that the progenitor of Omicron jumped from humans to mice, rapidly accumulated mutations conducive to infecting that host, then jumped back into humans, indicating an inter-species evolutionary trajectory for the Omicron outbreak,” the authors of the study wrote.

READ MORE: ‘Stealth Omicron’: New Subvariant BA.2 More Contagious, Say Experts

Possibility Behind Mouse Adapted SARS-CoV-2

Scientists believe that the mouse could have been infected with an older strain of Covid-19 in what is called a “reverse zoonotic transfer” following which the mutations that birthed Omicron took place in the mouse.

They believe that an earlier variant, from the lineage known as B.1.1, jumped from a human into a mouse in mid-2020. Over time, it evolved a range of adaptations to its new host before causing an infection in another human in late 2021. Eventually, it may have jumped back to humans, the study says.

Scientists added that if Omicron in fact mutated in a mouse, then all 45 mutations should be reflected in the “molecular spectrum” of the species. Their experiments revealed that the molecular spectrum of all virus variants is quite different from Omicron. In fact, it resembled the spectrum found in mouse cells.

According to their findings, it’s possible that the virus mutated in a mouse over the course of last year before jumping back to humans and later spreading like wildfire.

Implication Of The Findings

The Chinese study isn’t the first one that claims that the Omicron variant did originate in mice. Since the beginning of the pandemic in 2020, multiple reports have reported on mouse-adapted SARS-CoV-2.

A study by the Imperial College of London had found that the Omicron variant was now able to infect domestic poultry, horseshoe bats, and mice. While these findings will form a part of a larger discussion, there is one thing that remains certain and that is reinforcing the big uncertainty that the virus brings with it.

The findings go to show that the variant can now evolve in any direction and that there is no fixed route of transmission.

If the findings were to go by, then it seems that the virus now has an increased chance of infecting more animals, thereby expanding the array of hosts where it can originate from.

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The Chinese scientists allude to this. “Humans represent the largest known reservoir of Sars-CoV-2, and frequently come in contact with other animals, including livestock animals, pets, or wild animals that invade homes searching for food and shelter,” they said in their conclusion.

“Given the ability of Sars-CoV-2 to jump across various species, it appears likely that global populations will face additional animal-derived variants until the pandemic is well under control. Our study thus emphasises the need for viral surveillance and sequencing in animals, especially those in close contact with humans”.

The origins of the variant are among the key questions of research into the coronavirus right now, with implications for the future of the pandemic.

Many scientists have been skeptical of the animal-origin story of Omicron, although generally, they believe it’s too early to fully understand the origins of the variant. Nevertheless, it’s an important question as it could help us predict and prevent the rise of dangerous variants in the future.