The newly recognized omicron coronavirus variant could have developed in a nonhuman animal species, probably a rodent, some scientists recommend.
In line with this concept, an animal could have picked up SARS-CoV-2, the virus that causes COVID-19, round mid-2020, STAT reported. After accumulating many mutations within the animal, the altered coronavirus then would have made the bounce again to people. This chain of occasions will be described as reverse zoonosis, through which a pathogen jumps from people to animals, adopted by zoonosis, through which a germ passes from animals to people.
One key piece of proof in assist of this concept is that omicron diverged from different SARS-CoV-2 variants very far again in time, Kristian Andersen, an immunologist on the Scripps Analysis Institute, advised STAT.
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In contrast with different theories about omicron’s origin, such because it evolving in an immunocompromised particular person or in a human inhabitants with poor viral surveillance, “this reverse zoonosis adopted by new zoonosis appears extra more likely to me, given simply the obtainable proof of the actually deep department,” which means the early cut up from different coronavirus variants, “after which the mutations themselves, as a result of a few of them are fairly uncommon,” Andersen mentioned.
Omicron carries seven mutations that might enable the variant to contaminate rodents, akin to mice and rats; different variants of concern, like alpha, carry solely a few of these seven mutations, Robert Garry, a professor of microbiology and immunology at Tulane Medical College, advised STAT. (Garry additionally mentioned it is nonetheless unclear whether or not omicron emerged in an animal or human host.)
Along with these “rodent adaptation” gene variants, omicron carries a slew of mutations not seen in some other variations of SARS-CoV-2, and a few scientists take this as potential proof that the variant emerged in an animal host, Science reported.
“It’s attention-grabbing, simply how crazily totally different it’s,” Mike Worobey, an evolutionary biologist on the College of Arizona, advised Science in reference to omicron’s genome. “It does make me surprise if different species on the market can develop into chronically contaminated,” which may drive the emergence of latest variants with many mutations. However at this level, Worobey suspects that omicron developed in an immunocompromised human, not in an animal.
This is likely one of the main theories different specialists have prompt, Science reported. On this state of affairs, an immunocompromised particular person would have contracted COVID-19 however developed a continual an infection, through which they could not rid their physique of the virus; because it continued to multiply, it picked up many mutations. Proof means that the alpha variant could have acquired mutations on this manner, however this has but to be confirmed for omicron, Science reported.
If it did not emerge in both an animal or immunocompromised particular person, Omicron could have first appeared in a inhabitants with poor viral surveillance, which means it might have unfold and developed, unnoticed, for upwards of a 12 months. “I assume this developed not in South Africa, the place lots of sequencing is happening, however some place else in southern Africa throughout the winter wave,” Christian Drosten, a virologist at Charité College Hospital Berlin, advised Science.
However for this to be true, the affected inhabitants would have needed to be extraordinarily remoted, such that omicron did not unfold a lot past its ranks, mentioned evolutionary biologist Andrew Rambaut of the College of Edinburgh. “I am unsure there’s actually wherever on the earth that’s remoted sufficient for this type of virus to transmit for that size of time with out it rising in varied locations.”
Learn extra concerning the potential origin of the omicron variant in STAT and Science.
Initially revealed on Reside Science.