Virus News: American Scientist Warns That Newly Discovered Khosta-2 Sarbecoviruses Can Infect Humans And Will Be Worse Than SARS-CoV-2!
: Researchers from Washington State University-USA and Tulane University School of Medicine, Louisiana_USA are warning that the newly discovered Khosta-2 which belongs to the same family of sarbecoviruses as the SARS-CoV-2 virus, is not only able to infect human using the same receptors but will be resistant to all current vaccines and monoclonal therapeutics and will be more far more worse in terms of disease severity.
It has already been seen that spillover of sarbecoviruses from animals to humans has resulted in outbreaks of severe acute respiratory syndrome SARS-CoVs and the ongoing COVID-19 pandemic.
Interestingly, efforts to identify the origins of SARS-CoV-1 and -2 has resulted in the discovery of numerous animal sarbecoviruses–the majority of which are only distantly related to known human pathogens and do not infect human cells. The receptor binding domain (RBD) on sarbecoviruses engages receptor molecules on the host cell and mediates cell invasion.
The study team tested the receptor tropism and serological cross reactivity for RBDs from two sarbecoviruses found in Russian horseshoe bats.
Although these two viruses are in a viral lineage distinct from SARS-CoV-1 and -2, shockingly, the RBD from one virus, Khosta 2, was capable of using human ACE2 to facilitate cell entry.
Viral pseudotypes with a recombinant, SARS-CoV-2 spike encoding for the Khosta 2 RBD were resistant to both SARS-CoV-2 monoclonal antibodies and serum from individuals vaccinated for SARS-CoV-2.
The study findings demonstrate that sarbecoviruses circulating in wildlife outside of Asia also pose a threat to global health and ongoing vaccine campaigns against SARS-CoV-2.
The study findings were published in the peer reviewed journal: PLOS Pathogens.
The study team led by researchers at Washington State University’s Paul G. Allen School for Global Health discovered spike proteins from the bat virus, known as Khosta-2, that can infect human cells and are resistant to both monoclonal antibodies and serum from SARS-CoV-2 vaccine recipients and is likely to cause increased disease severity compare to the SARS-CoV-2 virus.
Both Khosta-2 and SARS-CoV-2 are coronaviruses that belong to the same subclass of coronaviruses known as sarbecoviruses.
Corresponding author, Dr Michael Letko, a virologist at Washington State University told Virus News
reporters at Thailand Medical News, “The study findings further demonstrates that sarbecoviruses circulating in wildlife outside of Asia such as places like western Russia where the Khosta-2 virus was found, also pose a threat to global health and ongoing vaccine campaigns against SARS-CoV-2.”
Dr Letko said that rather than just protecting against known versions of SARS-CoV-2, the finding of Khosta-2 underscores the necessity to create universal vaccinations to defend against sarbecoviruses in general.
added, “Right now, there are groups trying to come up with a vaccine that doesn’t just protect against the next variant of SARS-2 but actually protects us against the sarbecoviruses in general. Unfortunately, many of our current vaccines are designed for specific viruses we know infect human cells or those that seem to pose the biggest risk to infect us. But that is a list that’s everchanging. We need to broaden the design of these vaccines to protect against all sarbecoviruses.”
It was noted that despite the fact that hundreds of sarbecoviruses have recently been identified, mostly in Asian bats, the majority cannot infect human cells.
In late 2020, the Khosta-1 and Khosta-2 viruses were found in Russian bats, and at first, it seemed they posed little danger to humans.
Dr Letko added, “Genetically, these weird Russian viruses looked like some of the others that had been discovered elsewhere around the world, but because they did not look like SARS-CoV-2, no one thought they were really anything to get too excited about. But when we looked at them more, we were really surprised to find they could infect human cells. That changes a little bit of our understanding of these viruses, where they come from, and what regions are concerning.”
Dr Letko teamed with a pair of Washington State University faculty members, first author viral ecologist Dr Stephanie Seifert and viral immunologist Dr Bonnie Gunn, to study the two newly discovered viruses.
The study team determined Khosta-1 posed a low risk to humans, but worryingly, Khosta-2 demonstrated some troubling traits.
The study team found that like SARS-CoV-2, Khosta-2 can use its spike protein to infect cells by attaching to a receptor protein, called angiotensin-converting enzyme 2 (ACE2), found throughout human cells. They next set out to determine if current vaccines protect against the new virus.
Utilizing serum derived from human populations vaccinated for COVID-19, the study team saw that Khosta-2 was not neutralized by current vaccines.
The researchers also tested serum from individuals who were infected with the omicron variant, but the antibodies, too, were ineffective.
The study team said that the new virus is lacking some of the genes believed to be involved in pathogenesis in humans. There is a risk, however, of Khosta-2 recombining with a second virus-like SARS-CoV-2 or that there are some new genes in the virus that could lead to increased disease severity.
Dr Letko commented, “When you see SARS-2 has this ability to spill back from humans and into wildlife, and then there are other viruses like Khosta-2 waiting in those animals with these properties we really don’t want them to have, it sets up this scenario where you keep rolling the dice until they combine to make a potentially riskier virus.”
It was also noted that in the last decade, there has been isolated cases of small clusters of disease outbreaks with unknown causes leading to high mortality in places like China, Africa, India, Indonesia and Russia and in some cases, new viruses could have been at play but the outbreaks were limited and did not spread much. However, it is only a matter of time before another novel virus like SARS-CoV-2 starts to wreak havoc globally.
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