Close relatives of SARS-CoV-2 circulating undetected in bats for decades

Close relatives of SARS-CoV-2 circulating undetected in bats for decades

As the world continues to grapple with the coronavirus or COVID-19, a ream of researchers comprising of scientists from China, Europe, and the United States, has discovered that the lineage, which gave rise to the new virus has been circulating in bats for decades and probably includes other viruses having the ability to infect humans.

The findings indicate that "the lineage giving rise to SARS-CoV-2 has been circulating unnoticed in bats for decades".

"While there have been many studies about SARS-CoV-2, there is still a lot we don't understand about the virus yet".

"Humans certainly develop antibodies against other SARS-CoV-2 proteins, but it's the antibodies against spike that seem to be most important for protection", Whelan said. They also examined the phylogenetic histories for the non-recombinant regions and later made comparisons to find out the specific viruses that have had significant involvement in recombination events earlier. "To do that, we put together a diverse team with expertise in recombination, phylogenetic dating, virus sampling, and molecular and viral evolution".

The worldwide research team has suggested that it might be useful to conduct surveillance for more viruses closely related to SARS-CoV-2 along the region from Yunnan to Hubei.

The study got published in Nature Microbiology on July 28. It suggests that the two viruses, RaTG13 and SARS-CoV-2, share a single ancestral lineage and that SARS-CoV-2 is likely to have genetically diverged from related bat sarbecoviruses in 1948, 1969 or 1982.

The 40-70 years since Sars-CoV-2 diverged from other bat viruses, was also similar to the divergence time of the earlier, related Sars-CoV virus that led to an outbreak in 2002-2003.

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"Understanding the role of pet animals in this pandemic is very challenging at a time when clearly the research and medical focus has to be on human health", said Professor Nicola Decaro from the University of Bari in Italy.

The team found one of the older traits Sars-CoV-2 shared with its relatives was the receptor-binding domain (RBD) located on the Spike protein, which enables the virus to recognise and bind to receptors on the surfaces of human cells. University of Glasgow professor of computational virology David L Robertson said. "The capacity of the virus to infect human cells emerged in the bats themselves, not in pangolins".

"Whilst none of the tested animals were shedding virus at the time of sampling, vets and the public need to continue to be aware that pet animals living in COVID-19 households will nearly definitely have virus on them, and our research adds to the evidence that suggests they may also be infected", said Professor Alan Radford from Liverpool university.

The work points to the need for further surveillance of emerging diseases in humans and to carry out more sampling within wild bat populations, if we are to prevent future pandemics, he said.

"The key to successful surveillance is knowing which viruses to look for and prioritize those that can readily infect humans".

"We were too late in responding to the initial SARS-CoV-2 outbreak, but this will not be our last coronavirus pandemic", Boni noted.

"A much more comprehensive and real-time surveillance system needs to be put in place to catch viruses like this when case numbers are still in the double digits".

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