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 ancestor of the coronavirus could have lurked in animals for millions of years before jumping on humans, a virologist claimed.

The coronavirus, scientifically known as SARS-CoV-2, enabled humans to infect humans when it mutated into an animal and then jumped over species.

It occurred for the first time in China last year and the virus, which spread rapidly and was deadly to humans, has since infected at least 110 million people and killed 2.4 million.

Dr Emilia Skirmuntt, an evolutionary virologist at the University of Oxford, studies viruses that affect bats and says that it would probably have been a version of the virus for a long time.

Scientists believe that bats transmitted the virus to another species, which then transmitted it to humans, but Dr. Skirmuntt suggested that it could have been passed on to the intermediary.

What ‘species zero’ was, she told MailOnline, is still unclear. And scientists will probably never determine the exact moment at which the virus spread from animals to humans.

Experts suggested that pangolins could transmit the virus to humans, but Dr Skirmuntt said it was unlikely because it had apparently also become ill, meaning they would not be effective ‘reservoirs’ to incubate the virus.

The origins of the pandemic are still vague and China is accused of obscuring the true extent of the outbreak and failing to hand over important data to a World Health Organization team last month.

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

Emilia Skirmuntt, a virologist from Oxford University, said it was very difficult to say which animal the virus came 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 mutations that made it more effective by infecting other species and humans. This is how we got SARS-CoV-2. ‘

She disputes the theory that pangolins could be the intermediary between bats and humans.

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

“With pangolins, we have seen similar coronaviruses,” she said.

‘The problem is the coronaviruses we saw, which made them sick, and that should not happen to reservoir species.

‘The long-term co-evolution causes the pathogen to show more symptoms after infection.

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

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

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

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

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

Emilia Skirmuntt, an evolutionary virologist, fears they will never be identified, saying the virus would only affect small communities, but it would be difficult to identify it.

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

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

“It may be that we will never know who patient was zero.”

She added the evidence currently indicated on an animal infection, rather than a laboratory escape.

‘We know at the moment that there is more evidence to suggest the natural source of infection is that the leak is leaking from the laboratory.

‘These viruses tend to spread from animals to humans.

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

Dr Skirmuntt added: ‘It was perhaps also just a bat that jumped from bat to human. It is very difficult to say without having samples of all these animals available. ‘

She said when other coronaviruses – unlike those caused by Covid – had previously infected humans, they arrived via an intermediary.

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

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

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

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

‘Whether it’s political or time or difficult … But whether there are other reasons why the data is not available, I do not know. “One would just speculate.”

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

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

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

It also highlighted the smaller Asian yellow bat as a possible source, which is already known to cause coronaviruses that are common in East Asia.

The University of Liverpool team said in their paper: ‘Our results show the great underestimation of the potential scale of the new generation of coronavirus in wild and domestic animals.

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

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

There are perhaps more than 30 times more host species for coronaviruses than are currently known, according to them, all of which could potentially contain new strains of Covid-19.

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

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

CORONAVIRUS MUTTERS SLOWER THAN PREDICTION AND VARIANTS ARE NOT A CAUSE FOR PANIC

Coronavirus mutates more slowly than expected and variants are not cause for panic, an evolutionary virologist said.

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

These include the South African strain and the Brazilian strain, both of which have the E484K mutation that can make vaccinations less effective.

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

“We have to observe them. We knew it would happen.

‘In fact, this coronavirus develops more slowly than we expect from these types of viruses.

“We have to be careful, but we will see new mutations and new variants. This 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 occurs more and more in different variants, which helps us because we can predict how the virus will mutate further.

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

T SELL IMMUNITY IS MUCH MORE IMPORTANT THAN ANTICODIVES, BUT IS DIFFICULT TO DETECT

Immunity against T cells is much more effective than antibodies, a scientist said, but it is much harder to detect.

T-cell help is a part of the immune system that destroys infected cells, which limits the spread of the virus among those suffering from the disease and helps build antibodies – proteins that fight virus.

Both are caused by the coronavirus vaccines, which cause immunity and stop an infection if someone is exposed to the virus.

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

But Dr Emilia Skirmuntt, an evolutionary virologist at the University of Oxford, says it should be considered in conjunction 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 the immune memory and can remember the pathogen.

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

‘We can not really know how T-cell memory works in case of 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 initially expected. ‘

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

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