New mutation spread up spread of coronovirus

November 13, 2020 – The virus that causes COVID-19 is not the same strain that first appeared from China. A new study suggests that it has changed slightly which makes it more contagious to humans.

Compared to the original strain, people infected with the new strain – called 614G – have higher viral loads in their noses and throats, although they do not suffer any disease. But they are much more contagious to others.

“That kind of makes sense,” says Ralph Barrick, a professor of epidemiology, microbiology, and immunology at the University of North Carolina at Chapel Hill.

The new strain changes its spike protein – the regions of its outer shell that dock on our cells and infect them. The change makes it a more efficient hunter. It passes quickly from cell to cell in our body, copying itself at a furious pace.

Barik’s experiments help explain how the 614G strain, which first emerged in Europe in February, has quickly spread worldwide.

He said the virus likely outgrew the bats and discovered a new population of human hosts, with more than 7 billion people present on the planet. None of us have any immune immunity against it, so we are the main target. Viruses with genetic benefits that help them copy themselves faster and jump more quickly between hosts are versions that survive and will pass.

“So it can jump from one person to another, which is the most competitive virus in terms of maintaining the virus,” says Barrick, one of the world’s leading experts on coronovirus. His new study is published in the journal Science.

The new study supports earlier research by a team of scientists led by Bette Korber, PhD, at Los Alamos National Laboratory in New Mexico. The team first saw the rapid spread of the new strain and questioned whether the virus was not developing to easily pass between people.

In new experiments, animals infected with the new 614G strain passed it more quickly to healthy animals than those infected with the original strain.

Researchers at the University of Wisconsin at Madison infected 16 hamsters with the SARS-CoV-2 virus. Eight hamsters were infected with the new 614G strain. Eight others were infected with the original strain that was first identified in China. Each infected hamster was paired with a healthy hamster that was separated by a partition in a cage, so that the animals could not touch but breathe the same air. By the second day of the experiment, five of the eight healthy hamsters sharing the air with 614G strain-infected animals had fallen ill and were shedding the virus themselves, but none of the healthy hamsters infected with the original strain were ill. . The original strain eventually shook the healthy animals, but it took 2 more days for this to occur, proving that the changes helped speed up the spread of the virus

Barrick and his team also wondered whether changes to the structure of the virus would affect future treatments – including a vaccine – might work against it, as all treatments now in development are designed to combat the original strain China.

They tested antibodies extracted from the blood of those who survived COVID-19 infection on both new and old strains, and found how important those antibodies worked to neutralize the virus.

This is good news, as it means that those who overcome an infection with the original stress may still have some protection against the new strain.

In the US, the original strain was imported from China and began to circulate on the West Coast, while the new strain was imported from Europeans who were mainly traveling to New York and the rest of the East Coast.

Barik and his team also tested antibodies that are being developed as a treatment to give people passive immunity against the virus. They were also working well.

“Vaccines, which are all based on the original Chinese strain, create a good immune response that protects against this stress, so that’s good news,” he says.

Although current treatment and prevention efforts are not greatly affected by this change of virus, the mutation raises questions about how new strains are rapidly emerging and whether one of those problems may arise in the future. Barik says. .

Coronaviruses, as a group, are highly stable. They have a special molecule – correctly dubbed a proofreader – that ensures that the virus is copied correctly.

Because of this proofreader, the pace of emergence of these new strains of new coronovirus has been somewhat surprising to scientists who study them.

One development that Barik and other scientists are closely observing is the emergence of new strains found on mink farms in Denmark and the Netherlands that have been shown to infect humans.

Work is being done to confirm that at least one of those strains – the so-called cluster 5 virus – can develop substantial changes in its spike protein that helps it avoid vaccination.

Barrick says research needs to be verified, but early work suggests that the virus has changed to help mink infect more efficiently, while it also has the ability to infect humans .

When a virus develops in a way that allows it to be transmitted to an animal species, “it becomes more difficult to erase that virus,” he says.

Barrick says that if the virus continued to pass into the mink, if we vaccinated everyone in Denmark, but excluded the mink, the virus would hang on until enough new, susceptible hosts – usually young children – were found. And then jump back into humans. .

For this reason, he says, mink farms may need to take further steps, such as vaccinating their animals, or, at worst, killing their mink, controlling the spread.

WebMD Health News


Ralph Baric, PhD, William R. Kenan Jr., Professor, Department of Epidemiology, and Professor, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill.

Science: “The SARS-CoV-2 D614G variant demonstrates efficient replication ex vivo and transmission in vivo.”

Cell: “Tracking Changes in SARS-CoV-2 Spike: Evidence that D614G Increases COVID19 Virus Infection.”

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