Unexpected discovery of the variant origin of the SARS-CoV-2 virus in the UK

The SARS-CoV-2 virus variant discovered for the first time in the UK may have come from dogs, according to a study from Chinese scientists.
Researchers in Shanghai have tracked the initial evolution of the B117 variant, which caused the new Covid-19 wave in several countries, but were unable to trace its trace on virus samples. collected from people around the world.

However, when they expanded their study to animals, they discovered some early forms of B117 in dogs, including a sample taken in the US in July 2020. Artwork: AP “These initial variants included most or all of the B117 mutations in the Canidae breed and they could have infected humans after a rapid mutation,” Professor Chen Luonan and colleagues at the State Cell Biology Key Laboratory said in a report posted on biorxiv on April 16. The arrival of the B117 variant has puzzled researchers. After being isolated from two patients in Kent in southeast England and London in September 2020, the new variant of the SARS-CoV-2 virus quickly became the dominant strain in the UK and many other countries. the ability to spread more strongly than the original virus strain. Some experts believe that the variant may have emerged from the local community due to the selective pressures of antiviral drugs used during the pandemic. According to a popular theory, this variant suddenly appeared in England and then spread to many other parts of the world. However, this variant had nine mutations that were rarely found on previous human variants, said Chan and colleagues. These mutations do not appear in adjacent genes, but spread across the entire genome of the virus. The likelihood of these mutations occurring at the same time is very low. The Shanghai team of researchers believes that these nine mutations created one mutation after another. Their model also suggests that variations may have appeared outside the UK and spawned mutations that were present on non-human hosts. The dogs are the most likely animal in this case, followed by the weasels and the cats. Qu Liandong, a virology professor at the Harbin Veterinary Research Institute who was not involved in the study, said that more clear evidence is needed to support the hypothesis. The variations found in dogs do not quite resemble the first confirmed variant in a British patient, although the number of genetic sequences the researchers gathered from hundreds of thousands of patients was still overwhelming. small compared to the total number of patients in the world. Some of the early forms of the B117 variant were missed in the sample collection program, he said. However, if pets like dogs become hosts, “we will have a big problem,” said Professor Qu. “Nearly all of our measures to deal with disease so far have only considered humans. If the animals are also sick, it will completely change the situation,” he said. . When bird flu outbreaks occur in a chicken farm, all chickens are destroyed, even healthy ones, to prevent the risk of infection. Dogs are close friends of man. If they are able to carry or create variant SARS-CoV-2, they could suffer a similar fate, Qu said. Another solution is to inject animals with vaccines. “However, we cannot inject dogs with human vaccines. We need to develop completely new vaccines. Right now, we are still struggling in the campaign to vaccinate humans. Can the vaccination program be extended to both dogs and other animals? “asks Qu. There is growing concern that the B117 could make the dogs weaker. Veterinarians near London discovered a spike in pets, including dogs and cats, with myocarditis, and many of these were positive for the new variant of the SARS-CoV- virus. 2. Humans and animals have different immune systems and it is often difficult for viruses to be transmitted from one species to another. The SARS-CoV-2 virus is thought to have originated in bats and it takes decades to adapt in humans. When and where this virus spreads from animals to humans remains a mystery. The B117 variant has a special evolutionary process to increase infectivity, so it can be spread more easily from one host to another, says Chen’s team. Whether this process helps the variant of SARS-CoV-2 cross the species gap is still in need of further study, the experts said./.