The newly recognized omicron coronavirus variant could have advanced in a nonhuman animal species, probably a rodent, some scientists counsel.
In response to this idea, 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, by which a pathogen jumps from people to animals, adopted by zoonosis, by which a germ passes from animals to people.
One key piece of proof in assist of this idea is that omicron diverged from different SARS-CoV-2 variants very far again in time, Kristian Andersen, an immunologist on the Scripps Analysis Institute, instructed STAT.
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In contrast with different theories about omicron’s origin, such because it evolving in an immunocompromised individual or in a human inhabitants with poor viral surveillance, “this reverse zoonosis adopted by new zoonosis appears extra prone to me, given simply the out there proof of the actually deep department,” which means the early break up from different coronavirus variants, “after which the mutations themselves, as a result of a few of them are fairly uncommon,” Andersen stated.
Omicron carries seven mutations that may enable the variant to contaminate rodents, corresponding 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 Faculty, instructed STAT. (Garry additionally stated 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 another 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 fascinating, simply how crazily completely different it’s,” Mike Worobey, an evolutionary biologist on the College of Arizona, instructed Science in reference to omicron’s genome. “It does make me surprise if different species on the market can turn out to be chronically contaminated,” which might drive the emergence of recent variants with many mutations. However at this level, Worobey suspects that omicron advanced in an immunocompromised human, not in an animal.
This is among the main theories different specialists have instructed, Science reported. On this situation, an immunocompromised individual would have contracted COVID-19 however developed a continual an infection, by 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 method, however this has but to be confirmed for omicron, Science reported.
If it did not emerge in both an animal or immunocompromised individual, Omicron could have first appeared in a inhabitants with poor viral surveillance, which means it might have unfold and advanced, unnoticed, for upwards of a 12 months. “I assume this advanced not in South Africa, the place loads of sequencing is occurring, however someplace else in southern Africa throughout the winter wave,” Christian Drosten, a virologist at Charité College Hospital Berlin, instructed 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, stated evolutionary biologist Andrew Rambaut of the College of Edinburgh. “I am undecided there’s actually anyplace on the planet that’s remoted sufficient for this kind of virus to transmit for that size of time with out it rising in varied locations.”
Learn extra in regards to the potential origin of the omicron variant in STAT and Science.
Initially printed on Stay Science.