Coronavirus News: Research Shows Many Types Of Coronaviruses Similar In Traits to SARS-CoV-2 If Not More Potent Just Waiting To Jump Over To Humans
: An international research team of Chinese, European, and U.S. scientists, say that the SARS-CoV-2 lineage responsible for the COVID-19 pandemic has been circulating in bats for 40–70 years and likely includes other viruses with the ability to infect humans. This finding, which is derived from a newly constructed evolutionary history of SARS-CoV-2, has implications for the prevention of future pandemics stemming from this lineage.
The research findings were published in the journal: Nature Microbiology. https://www.nature.com/articles/s41564-020-0771-4#Sec6
In order to put together SARS-CoV-2’s evolutionary history, the scientists had to account for recombination events, which occur frequently in coronaviruses and which complicate inquiries into a pathogen’s origins.
Dr Maciej Boni, Associate Professor of biology at Penn State and the lead author of a study explained to Thailand Medical news, “Coronaviruses have genetic material that is highly recombinant, meaning different regions of the virus’s genome can be derived from multiple sources. This has made it difficult to reconstruct SARS-CoV-2’s origins. You have to identify all the regions that have been recombining and trace their histories. To do that, we put together a diverse team with expertise in recombination, phylogenetic dating, virus sampling, and molecular and viral evolution.”
The team used three different bioinformatic approaches to identify and remove the recombinant regions within the SARS-CoV-2 genome.
The study team reconstructed phylogenetic histories for the nonrecombinant regions and compared them to each other to see which specific viruses have been involved in recombination events in the past.
Dr Boni added, “We find that the sarbecoviruses; the viral subgenus containing SARS-CoV and SARS-CoV-2, undergo frequent recombination and exhibit spatially structured genetic diversity on a regional scale in China. SARS-CoV-2 itself is not a recombinant of any sarbecoviruses detected to date, and its receptor-binding motif, important for specificity to human ACE2 receptors, appears to be an ancestral trait shared with bat viruses and not one acquired recently via recombination.”
The researchers maintained that the results generated by the three bioinformatic approaches were consistent with Bayesian evolutionary rate and divergence date estimates as well as with two different prior specifications of evolutionary rates based on HCoV-OC43 and MERS-CoV.
Furthermore the researchers estimated that divergence dates between SARS-CoV-2 and the bat sarbecovirus reservoir were 1948 (95% highest posterior density (HPD): 1879–1999), 1969 (95% HPD: 1930–2000), and 1982 (95% HPD: 1948–2009).
These study findings led the scientists to conclude that viruses closely related to SARS-CoV-2 have been circulating in horseshoe bats for many decades.
Dr Boni added, “The unsampled diversity descended from the SARS-CoV-2/RaTG13 common ancestor forms a clade of bat sarbecoviruses with generalist properties with respect to their ability to infect a range of mammalian cell
s that facilitated its jump to humans and may do so again.”
The study team found that one of the older traits that SARS-CoV-2 shares with its relatives is the receptor-binding domain (RBD) located on the spike protein, which enables the virus to recognize and bind to receptors on the surfaces of human cells.
The researchers emphasized that preventing future pandemics will require better sampling within wild bats and the implementation of human disease surveillance systems that are able to identify novel pathogens in humans and respond in real time.
Senior author, Dr David L. Robertson, PhD, Professor of computational virology, MRC-University of Glasgow Centre for Virus Research said, “The key to successful surveillance is knowing which viruses to look for and prioritizing those that can readily infect humans. We should have been better prepared for a second SARS virus.”
Dr Boni added, “We were too late in responding to the initial SARS-CoV-2 outbreak but this will not be our last coronavirus pandemic. 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.”
A decent surveillance system of the kind suggested by Dr Boni is in line with recommendations from another recent study, one that argues for investments in preventive efforts.
The research, prepared by scientists from Boston University, Princeton University, Duke University, Conservation International, and other institutions, indicated that “preventive efforts would be substantially less than the economic and mortality costs of responding to these pathogens once they have emerged.” https://science.sciencemag.org/content/369/6502/379
The research team assessed the cost of monitoring and preventing disease spillover that is driven by the unprecedented loss and fragmentation of tropical forests and by the burgeoning wildlife trade. They discovered that significantly reducing transmission of new diseases from tropical forests would cost, globally, between US$22.2 and US$30.7 billion each year.
In comparison, they found that the COVID-19 pandemic will likely end up costing between US$8.1 and US$15.8 trillion globally or roughly 500 times as costly as what it would take to invest in proposed preventive measures. To estimate the total financial cost of COVID-19, researchers included both the lost gross domestic product and the economic and workforce cost of hundreds of thousands of deaths worldwide.
The researchers said collectively, “We invest relatively little toward preventing deforestation and regulating wildlife trade, despite well-researched plans that demonstrate a high return on their investment in limiting zoonoses and conferring many other benefits.”
For years researchers and environmental activists have been trying to draw the world’s attention to the much harm caused by the rapid destruction of tropical forests. One of these harms is the emergence of new diseases that are transmitted between wild animals and humans, either through direct contact or through contact with livestock that is then eaten by humans. The SARS-CoV-2 virus which has so far infected more than 15 million people worldwide appears to have been transmitted from bats to humans in China.
Dr Les Kaufman, PhD, one of the resarch co-authors and a Boston University Professor of biology said, “Much of this traces back to our indifference about what has been occurring at the edges of tropical forests.”
In order to reduce disease transmission, Dr Kaufman and his collaborators propose expanding wildlife trade monitoring programs, investing in efforts to end the wild meat trade in China, investing in policies to reduce deforestation by 40%, and fighting the transmission of disease from wild animals to livestock.
Dr Kaufman added, “The pandemic gives an incentive to do something addressing concerns that are immediate and threatening to individuals, and that’s what moves people. There are many people who might object to the United States fronting money, but it’s in our own best interest. Nothing seems more prudent than to give ourselves time to deal with this pandemic before the next one comes.”
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