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URL: http://www.avianflutalk.com/forum_posts.asp?TID=44994 Printed Date: March 28 2024 at 11:17am
Topic: SARS-3 ????Posted By: Dutch Josh
Subject: SARS-3 ????
Date Posted: September 24 2022 at 5:29am
“We found that the spike from virus, Khosta-2, could infect cells similar to human pathogens using the same entry mechanisms, but was resistant to neutralization by serum from individuals who had been vaccinated for SARS-CoV-2.”.
Khosta-2, a sarbecovirus discovered in Russia, has been shown to interact with the same entry receptor as SARS-CoV-2. In this study, we tested how well the spike proteins from these bat viruses infect human cells under different conditions. We found that the spike from virus, Khosta-2, could infect cells similar to human pathogens using the same entry mechanisms, but was resistant to neutralization by serum from individuals who had been vaccinated for SARS-CoV-2.
To assess if the ACE2-dependent Khosta 2 RBD and SARS-CoV-2 RBD were cross-reactive, we incubated pseudotyped particles with increasing amounts of the SARS-CoV-2 RBD-specific monoclonal antibody, Bamlanivimab. Surprisingly, while SARS-CoV-2 spike was effectively neutralized by the antibody, the SARS-CoV-2 spike with the Khosta 2 RBD was completely resistant, suggesting little cross-reactivity between the two RBDs
The spillover of SARS-CoV-2 into humans has caused one of the most devastating pandemics in recorded history. Human-animal interactions have led to transmission events of SARS-CoV-2 from humans to wild and captive animals. However, many questions remain about how extensive SARS-CoV-2 exposure is in wildlife, the factors that influence wildlife transmission risk, and whether sylvatic cycles can generate novel variants with increased infectivity and virulence. We sampled 18 different wildlife species in the Eastern U.S. and detected widespread exposure to SARS-CoV-2 across wildlife species. Using quantitative reverse transcription polymerase chain reaction and whole genome sequencing, we conclusively detected SARS-CoV-2 in the Virginia opossum and had equivocal detections in six additional species. Species considered human commensals like squirrels, and raccoons had high seroprevalence, ranging between 62%-71%, and sites with high human use had three times higher seroprevalence than low human-use areas. SARS-CoV-2 genomic data from an infected opossum and molecular modeling exposed previously uncharacterized changes to amino acid residues observed in the receptor binding domain (RBD), which predicts improved binding between the spike protein and human angiotensin-converting enzyme (ACE2) compared to the dominant variant circulating at the time of isolation. These mutations were not identified in human samples at the time of collection. Overall, our results highlight widespread exposure to SARS-CoV-2 in wildlife and suggest that areas with high human activity may serve as important points of contact for cross-species transmission. Furthermore, this work highlights the potential role of wildlife in fueling de novo mutations that may eventually appear in humans.
DJ...of course bats themselves have (round) 30 corona virus types....so mutations there could bring new types of CoViD/SARS...CoViD-spread via birds (in combination with flu types) could be another bad change...
TMN claims the real number of cases/deaths are 5 to 6 time the official numbers...640 million cases, 6,6 million deaths would then translate to 3,2/3,8 billion cases-almost 50% of the global population....(if you would exclude reinfections...33 to 39 million deaths....
One could argue the spread in humans may bring SARS-3...depending on definition mutations may result in variants very different from the "Wuhan-wild type"....
There was the idea SARS-1 infection would result in immunity against "SARS-2"...I think that idea is history by now....
------------- We cannot solve our problems with the same thinking we used when we created them. ~Albert Einstein
Posted By: Dutch Josh
Date Posted: January 04 2023 at 9:34am
1/ HOW DIFFERENT IS XBB.1.5 AND HOW WORRYING IS IT? Very. This graphic from the linked paper shows it is as different from the Wuhan variant (now known as WT = Wild Type) of SARS-COV-2 as WT is from SARS-COV (the virus which caused SARS1 in 2003). https://biorxiv.org/content/10.1101/2022.11.23.517532v1.full.pdf…
2/ The briefest of explanations of the graphic, more in the paper:
It shows the degree of neutralisation of the different variants by the sera of people with a selection of vaccination options and also people who are post infection.
3/ D614G refers to a mutation on the spike protein of WT. As you can see, all the post-vaccination and post-infection sera exhibit their maximum neutralising activity against the D614G-containing WT.