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

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

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The coronavirus ancestor could have been lurking in animals for millions of years before reaching humans, said a virologist.

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

This happened for the first time last year in China and the virus – which has spread rapidly and is deadly to humans – has already infected at least 110 million people and killed 2.4 million.

Dr. Emilia Skirmuntt, an evolutionary virologist at the University of Oxford, is studying viruses that affect bats and said they probably carried a version of the virus for a long time.

Scientists believe that bats transmitted the virus to another species, which transmitted it to humans, but Dr. Skirmuntt suggested that it could have skipped the middleman.

What was ‘zero species’, she told MailOnline, was not yet clear. And scientists would probably never identify the exact moment when the virus spread from animals to people.

Experts suggested that pangolins could have passed the virus on to humans, but Skirmuntt said this was unlikely because it seemed to make them sick too, meaning they would not be efficient “reservoirs” for incubating the virus.

The origin of the pandemic is still hazy and China was accused of covering up the true extent of the outbreak and of failing to deliver important data to a World Health Organization team last month.

Emilia Skirmuntt, a virologist at the University of Oxford, said it is very difficult to say which animal the virus came from due to the very small number of samples

Emilia Skirmuntt, a virologist at the University of Oxford, said it is very difficult to say which animal the virus came from due to the very small number of samples

Dr. Skirmuntt told MailOnline: ‘The virus needed to mutate to be able to reach humans.

“The ancestor of this coronavirus was an animal species that was a reservoir for millions of years and then there were some mutations that made it more efficient for infecting 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 incubate viruses that are relatively harmless to them, but can be dangerous to people or other animals, such as the Nipah virus.

“With pangolins, we saw similar coronaviruses,” she said.

“The problem is the coronaviruses that we saw in them, that made them sick and that shouldn’t happen with the reservoir species.

“The long-term coevolution causes the pathogen to show more symptoms after infection.

“Only one coronavirus protein seen in pangolins is more than 90 percent similar to SARS-CoV-2, and it should be a larger proportion to actually say that it is the intermediate species.”

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

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

‘WE CAN NEVER FIND THE COVID ZERO PATIENT’, VIROLOGIST SAYS

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

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

‘It will be very difficult to find him,’ she told MailOnline.

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

“We may never know who patient zero was.”

She added that the evidence currently pointed to an animal infection, rather than a laboratory escape.

‘We now know that there is more evidence pointing to the natural source of infection than the leak from the laboratory.

‘These viruses tend to jump from animals to humans.

‘Scientists have been waiting for the coronavirus pandemic now for more than several years. We have research and work on this, so it’s not unexpected. ‘

Dr. Skirmuntt added: ‘It may have been just a bat that jumped from bat to human. It is very difficult to say without samples available from all of these animals.

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

Scientists suspect that the same route was taken by SARS-CoV-2, but it is difficult to be sure because the beginning of the pandemic is poorly documented.

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

WHO asked for details of the first 174 cases detected in Wuhan in early December 2019, half of which were linked to the seafood market, but only a summary has been provided.

“That’s why we insist on asking for it,” said Professor Dwyer. ‘Why doesn’t that happen, I couldn’t comment.

‘Whether it is political, time or difficult … But if there are other reasons why the data is not available, I don’t know. It would just be speculating. ‘

And the importance of animals in spreading disease remains to be investigated, with a study published in the journal Nature Communications this week suggesting that the next pandemic may come from hedgehogs.

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

His model “implicated” the common hedgehog, the European rabbit and the domestic cat as possible hosts for new coronaviruses.

He also highlighted the smaller Asian yellow bat as a possible source, which is already known to host common coronaviruses in East Asia.

The University of Liverpool team said in their article: ‘Our results demonstrate a great underestimation of the potential scale of the new generation of coronavirus in wild and domesticated animals.

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

They said the emergence of new strains was an ‘immediate threat to public health’.

There may be more than 30 times more host species of coronavirus than currently known, they say, that could harbor new strains of Covid-19.

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

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

CORONAVIRUS IS MUTTED MOST SLOWLY THAN ANTICIPATED AND VARIANTS ARE NOT A CAUSE OF PANIC

The coronavirus is mutating more slowly than expected and the variants are not a cause for panic, said an evolutionary virologist.

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

They include the South African strain and the Brazilian strain, both with the E484K mutation that can make vaccines less effective.

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

‘We must watch them. We knew it would happen.

“In fact, this coronavirus is evolving and mutating more slowly than we expected from this type of virus.

‘We must be cautious, 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 the design of future vaccines.

“What is interesting is that this mutation appears more and more in different variants, which helps us because we can predict how the virus will undergo more mutations.

‘Right now we can see the progression and evolution of this virus.’

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

T-cell immunity is much more effective than that of antibodies, one scientist said, but it is much more difficult to detect.

T cells help are a part of the immune system that destroys infected cells, reducing the spread of the virus in people suffering from the disease, and helping to build antibodies – proteins that fight viruses.

Both are triggered by vaccines against the coronavirus, which stimulate immunity and prevent an infection if someone is exposed to the virus.

Scientists recently warned about variants of the virus that appear to be more able to evade antibodies, possibly opening the door for reinfection.

But Dr. Emilia Skirmuntt, an evolutionary virologist at the University of Oxford, says they must be considered together with 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 immune memory and can resemble the pathogen.

“Most of our tests after vaccination and infection are based on antibodies because they are much easier to detect. T cells are not so easy to detect.

“We can’t really say how T cell memory works in the event of an infection or vaccination, but we know that it is much more important.

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

While there are concerns about new variants, research shows that the current crop of vaccines still prevents anyone infected with them from developing a serious infection or dying from the disease.

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