Did Omicron evolve in a RODENT? Scientist sasy sheer number of mutations ...

Did Omicron evolve in a RODENT? Scientist sasy sheer number of mutations ...
Did Omicron evolve in a RODENT? Scientist sasy sheer number of mutations ...

The super-mutant Omicron strain of Covid causing worldwide panic may have evolved in rodents, a scientist has theorised.

The mysterious origin of the heavily mutated strain of Covid has puzzled experts since South African scientists alerted the world to is existence last week. 

Omicron has 32 mutations on its spike proteins alone, nearly five times more than Delta, and there are concerns its highly divergent nature could make it it both more transmissible and that vaccines will be less effective at preventing infection. 

It has also come to light in recent days that Omicron has effectively evolved in the dark, unobserved by scientists, having split off in evolutionary terms from other variants such as Alpha and Delta sometime in the middle of last year.

While a popular theory is that Omicron emerged in an immunocompromised patient, possibly with undiagnosed AIDS. This would have given the virus had time to adapt to the patient's immune system resulting in numerous mutations.

But Professor Kristian Andersen, an immunologist at the Scripps Research Institute in California, has theorised that the virus that would become Omicron may have evolved in rodents - known to be carriers of the coronavirus - after an infected human passed the virus to them. 

This would explain why it split off from its evolutionary branch and 'vanished' at some point in 2020 and re-entered the population with so many highly unusual mutations, many never seen before.

Omicron's ancestor then would have adapted to infect the animal host, resulting in its heavily mutated nature, before passing back to humans and then rapidly spreading to other people in a process called 'reverse zoonosis'. 

Professor Andersen based the theory on the fact that while Omicron diverged from other Covid variants in the middle of last year, genomic sampling suggested it only started circulating in people sometime in October this year.  

What happened in between these two periods is the mystery behind what has made Omicron so different. 

Could Omicron have evolved in rodents? One scientists says a widely popular theory of the new supermutant Covid variant evolving in an immunocompromised patient doesn't stack up

Could Omicron have evolved in rodents? One scientists says a widely popular theory of the new supermutant Covid variant evolving in an immunocompromised patient doesn't stack up 

Omicron is nearly five times more mutated than Delta in terms of its spike proteins. Delta's mutations gave it an edge over Alpha allowing it to outcompete its predecessor and become the dominant strain. There are fears Omicron will do the same.

Omicron is nearly five times more mutated than Delta in terms of its spike proteins. Delta's mutations gave it an edge over Alpha allowing it to outcompete its predecessor and become the dominant strain. There are fears Omicron will do the same. 

A week on from its discovery in Southern Africa, Omicron has spread to dozens of countries

A week on from its discovery in Southern Africa, Omicron has spread to dozens of countries 

A total of 42 cases of Omicron have now been detected in the UK, 22 in England and 10 in Scotland, while the vaccination status of the infected individuals is unknown none have required hospitalisation 

While adding that this is only theoretical Professor Andersen said in a Twitter post he favoured a zoonic, animal-based, origin for Omicron as 'the lineage is old and undetected circulation in immunocompromised patient(s) for this long seems unlikely' and that Covid has been shown to jump between species previously. 

Secondly, is that several of Omicron's mutations have also been in rodent species such as mice and hamsters. 

WHAT MUTATIONS DOES OMICRON HAVE? 

A group of mutations — including K417N, S477N, E484A and N501Y — are thought to help Omicron dodge antibodies that usually help fight off the virus.

And N501Y, which was previously seen on Alpha, also helps the virus bind to the body's cells more easily, allowing for it to enter the body and replicate more efficiently.

Meanwhile, it has 26 mutations on its spike protein that haven't been seen in previous variants.

Three mutations found on the furin cleavage site may increase Omicron’s transmissibility. These include P681H, which was previously seen in Alpha, as well as H655Y and N679K, which scientists spotted in the Gamma strain.

A series of mutations may help the virus bind to the human cell and help Omicron escape the body’s immune response. These include T478K, which was also on Delta and Q498R, which has not been seen on variants of concerns before.

And missing mutations, including 105-107

Two mutations in the nucleocapsid — R203K and G204R, found on the Alpha and Gamma strains — may be associated with increased infectivity. 

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One of the theories on Covid's origins is that it originally jumped from an animal species such as bats to humans, and the virus has since been found in mink from fur farms in Denmark, and just last night reports emerged of the virus being found in deer in Canada.  

Professor Andersen added that while many scientists have concluded Omicron came from an immunocompromised person, such as HIV patient, it was too early to call.  

'While that's certainly possible, we don't have any data showing that's the case. Let's keep all hypotheses open,' he wrote. 

Asked about theory British experts said they still still favoured the immunocompromised patient theory.

Responding to the theory Professor David Livermore, a microbiologist at the University of East Anglia said while he acknowledged Omicron had split from it ancestors some time ago, he added that an immunocompromised patient theory was likely the origin of the variant's mutated nature. 

'Omicron is a long way from its ancestors and has an unusual combination of multiple changes,' he said. 

'More likely that it has been selected under strong selective pressure, for example in a chronically-infected immunosuppressed patient.'

Professor Lawrence Young, a virus expert at Warwick Medical School said we are in the very early days of understanding Omicron and its mutations. 

'My view, however, is that these folk can do as much modelling as they like but using this in an attempt to predict the biological behaviour of the virus is, at best, very speculative,' he said.

'It’s very difficult to predict what this combination of mutations really means for infectiousness and immune evasion.'

Professor Young added that previous research points still suggests an immunosuppressed Covid patient having the virus for months as the likely origin of Omicron.  

'Differential selective pressure in an immunocompromised host can serve as a breeding ground for the emergence of variants including those that are associated with immune escape,' he said. 

'There are several reports of prolonged infection in immunocompromised individuals (70- to more than 100 days) including transplant recipients, cancer patients and people undergoing immunosuppressive drug therapy for autoimmune disease that results in the generation of variants that may have increased transmissibility and immune evasion.

'These variants could then spread to other people – especially those who are unvaccinated.'

As of yesterday 42 cases of Omicron have been detected in the UK, all the cases are reported to be mild and not require hospitlaisation but the vaccination status of the infected has not been disclosed by the health authorities.

The mutant strain is rapidly becoming the dominant variant of Covid in South Africa.

Data in South Africa shows the R-rate has soared to over three per cent in recent weeks as Omicron took hold in Gauteng province

Data in South Africa shows the R-rate has soared to over three per cent in recent weeks as Omicron took hold in Gauteng province

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