CORONAVIRUS has mutated 30 times with the deadlier strain infecting Europe, scientists have discovered.
Researchers from Zhejiang University in China say the killer virus has evolved into multiple different strains since it jumped from animals to humans in December.
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And they claim that the most lethal strains are the ones that are rapidly spreading throughout Europe.
It comes as the UK is set to become the worst hit nation in Europe – with coronavirus deaths yesterday reaching 16,509.
The authors say their findings are the first to reveal how the mutation could affect the severity of the disease.
Scientists believe the virus – known as Sars-CoV-2 – is constantly mutating to overcome immune system resistance in different populations.
The researchers made their revelation after assessing viral strains from 11 Chinese coronavirus patients.
The team, led by Professor Li Lanjuan, tested how effectively the virus could infect and kill human cells in the laboratory.
The amount of the virus, dubbed by experts as the viral load, was analysed in all the cells after one, two, four and eight hours, as well as the next day and 48 hours later.
And the experts also explored whether the virus structurally changed the cell during infection, known as the cytopathic effects, up to three days after the experiment.
They found that the most aggressive strains created up to 270 times as much viral load as the least deadly type.
And Professor Li and her team revealed that the strains that produced the highest viral load led to a "higher cell death ratio".
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Writing in the study, which is published on medRxiv.org, the team said: "Our results show the observed mutations can have a direct impact on the viral load and CPE.
"This finding suggests the observed mutations in our study… can significantly impact the pathogenicity (the ability to cause disease) of SARS-CoV-2."
The scientists found some of the deadliest mutations in Zhejiang, where the university is located.
These strains had also been seen in several hard-hit European countries such as Italy and Spain – before spreading to the US epicentre New York.
However, some of the milder mutations were the varieties mainly found in the US, including Washington state, which could be the strain that shut down Wuhan, the city where the pandemic began in December.
Despite this, the researchers pointed out that the "full mutational diversity of the virus in Wuhan in the early days is still unknown".
The researchers warned that just because the mutations were milder, it didn't mean there was a low risk of mortality.
Ten of the 11 patients who were involved in the new study had clear links with Wuhan, where the virus originated.
Eight of the patients were men, and three were women and all of the participants, aged between four months and 71, recovered.
Two patients in Zhejiang, one in their 30s and one in their 50s, became severely ill after contracting weaker strains.
While both of the patients recovered, the older patient needed treatment in a hospital's intensive care unit.