Covid’s ancestor ‘lurked animals for millions of years before infecting humans’

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The ancestor of the coronavirus could have lurked in animals for millions of years before it sprang onto humans, a virologist claims.

The coronavirus, known scientifically as SARS-CoV-2, became able to infect humans when it mutated while in an animal and then jumped across species.

This first happened in China last year, and the virus – which was both fast-spreading and proved to be deadly to humans – has since infected at least 110 million people and killed 2.4 million people.

Dr. Emilia Skirmuntt, an evolutionary virologist at the University of Oxford, studies viruses that affect bats and said it was likely they carried some version of the virus for a long time.

Scientists believe that bats passed the virus on to another species who then passed it on to humans, but Dr. Skirmuntt suggested it could have skipped the middleman.

What ‘kind of zero’ was, she told MailOnline, was still unclear. And scientists would likely never determine the exact time when the virus spread from animals to humans.

Experts had suggested that pangolins could have transmitted the virus to humans, but Dr. Skirmuntt said this was unlikely because it also seemed to make them sick, meaning they would not be efficient ‘reservoirs’ for incubating the virus.

The origins of the pandemic are still hazy, and China is accused of obscuring the true magnitude of the outbreak and failing to hand over key data to a World Health Organization team last month.

Emilia Skirmuntt, a virologist from the University of Oxford, said it was very difficult to tell which animal the virus was from due to the very small number of samples

Emilia Skirmuntt, a virologist from the University of Oxford, said it was very difficult to tell which animal the virus was from due to the very small number of samples

Dr. Skirmuntt told MailOnline: ‘The virus had to mutate in order to jump on people.

The ancestor of this coronavirus was an animal species that was reservoirs for millions of years, and then there were some mutations that made it more efficient to infect other species and humans. That’s how we got SARS-CoV-2. ‘

She contested the theory that pangolins may have been the intermediate species between bats and humans.

Bats are known to hatch viruses that are relatively harmless to them but can be dangerous to humans or other animals, such as the Nipah virus.

“We have seen similar coronaviruses in pangolins,” she said.

‘The problem is that the coronaviruses we’ve seen in them made them sick and that shouldn’t happen with reservoir strains.

‘Long-term co-evolution means that the pathogen shows more symptoms when infected.

“ Only one coronavirus protein found in pangolins is over 90 percent comparable to SARS-CoV-2, and it should be a larger proportion to really say this is the intermediate species.

Bats are likely the source of the Covid-19 coronavirus, scientists say, as they are known to carry similar viruses without getting sick (stock image)

Bats are likely the source of the Covid-19 coronavirus, scientists say, as they are known to carry similar viruses without getting sick (stock image)

‘MAYBE WE WILL NEVER FIND COVID’S PATIENT ZERO,’ SAYS VIROLOGIST

Scientists are still trying to identify patient zero – or the first person to be infected with the SARS-CoV-2 virus that caused the pandemic.

Emilia Skirmuntt, an evolutionary virologist, fears they will never be identified, saying the virus only affected small communities at first, making it difficult to identify.

“It will be very difficult to find it,” she told MailOnline.

‘Most pandemics have certain stages. There is always a stage where we cannot see the pathogen because it spreads in small communities.

“We may never know who was patient zero.”

She added the evidence that currently indicates an infection from animals, rather than an escape from the lab.

‘We now know that there are more clues to the natural source of infection than the leak from the lab.

‘These viruses tend to jump from animal to human.

Scientists had been expecting the pandemic caused by the coronavirus for more than a few years now. We have research and papers on that, so it’s not unexpected. ‘

Dr. Skirmuntt added, “It could also just be a bat that jumped from bat to human. It is difficult to say that samples are not available from all these animals. ‘

She said that when other coronaviruses – other than the one that causes Covid – had previously infected humans, they had arrived through an intermediate strain.

Scientists suspect that the same route may have been taken by SARS-CoV-2, but it is difficult to know for sure because the start of the pandemic is poorly documented.

World Health Organization microbiologist Dominic Dwyer, who was part of the research team sent to China, said authorities in the country had refused to hand over data from early cases of the pandemic.

The WHO asked for details on the first 174 cases discovered in Wuhan in early December 2019, half of which were related to the fish market, but was only given a summary.

“That’s why we kept asking,” said Professor Dwyer. I could not comment on why that does not happen.

‘Whether it’s political or time or difficult … But if there are any other reasons why the data is not available, I don’t know. You would only speculate. ‘

And the importance of animals in the spread of disease is still being explored, with a study published this week in the journal Nature Communications suggesting the next pandemic could come from hedgehogs.

British researchers used machine learning to predict associations between 411 strains of coronavirus and 876 potential mammalian host species.

Their model “implied” the common hedgehog, European rabbit and domestic cat as potential hosts for new coronaviruses.

It also highlighted the less Asian yellow bat as a possible source, already known to harbor coronaviruses common in East Asia.

The University of Liverpool team said in their paper: ‘Our results demonstrate the major undervaluation of the potential size of new coronavirus generation in wild and domestic animals.

“These hosts are new targets for the surveillance of new human pathogenic coronaviruses.”

They said the emergence of new species is an “imminent threat to public health.”

There are possibly over 30 times more coronavirus host species than are currently known, they say, all of which could potentially harbor new strains of Covid-19.

In addition, they estimate that there are more than 40 times more mammalian species with four or more strains of coronavirus than previously observed.

Some mammals identified in the study as possible hosts for new strains of coronavirus – such as horseshoe bats, palm civets and pangolins – have already been linked to SARS-CoV-1, which triggered the 2003 SARS outbreak, or SARS-CoV-2 , which causes Covid-19.

CORONAVIRUS MUTERT LONGER THAN EXPECTED AND VARIANTS DO NOT CAUSE PANIC

Coronavirus mutates more slowly than expected and variants are no cause for alarm, says an evolutionary virologist.

Many different strains of the virus have already been identified, but only a few are of concern to scientists.

They include the South African strain and the Brazilian strain, both of which have the E484K mutation that could make vaccines less effective.

Dr. Emilia Skirmuntt told MailOnline that the new variants should not be a source of panic.

‘We have to observe them. We knew it was going to happen.

In fact, this coronavirus evolves and mutates more slowly than we expected from these types of viruses.

‘We have to be careful, but we will see new mutations and new variants. It is not unexpected. ‘

She added that the E484K mutation, seen in several new variants, could help predict future vaccine design.

‘Interestingly, this mutation is increasingly occurring in different variants, which helps us because we can predict how the virus will mutate further.

“Right now we can see the progression and evolution of this virus.”

T-CELL IMMUNITY IS MUCH MORE IMPORTANT THAN ANTIBODIES, BUT IS HARDER TO DETECT

Immunity from T cells is much more effective than that of antibodies, one scientist has said, but this is much more difficult to detect.

The help of T cells is part of the immune system that destroys infected cells, inhibits the spread of the virus in people suffering from the disease, and helps build antibodies – virus-fighting proteins.

Both are activated by the coronavirus vaccines, which trigger immunity and stop infection if someone is exposed to the virus.

Scientists have recently raised the alarm about variants of the virus that appear to be better able to evade antibodies and potentially open the door to reinfection.

But Dr. Emilia Skirmuntt, an evolutionary virologist at the University of Oxford, says these should be considered alongside T cells to fully understand the impact of variants on vaccine immunity.

“We found that T cell immunity is more important than antibody immunity,” she said.

‘T cells are more important because they are the immune memory and they can remember the pathogen.

‘Most of our tests after vaccinations and infection are based on antibodies because they are much easier to detect. T cells are not that easy to detect.

‘We can’t really say how T cell memory works in infection or vaccination, but we know it’s much more important.

T cells are the main defense against coronaviruses. That probably means that the immune memory will last much longer than we initially expected. ‘

While there is concern about new variants, research shows that current vaccines still prevent someone infected with them from developing a serious infection or dying from the disease.

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