The finding that pigs, chickens, and ducks do not appear susceptible to infection is particularly fortuitous, as farmed animals can often provide an emerging virus a safe harbor, and an evolutionary playground in which to experiment (see https://afludiary.blogspot.com/2020/11/preprint-recurrent-mutations-in-sars.html" style="margin: 0px; padding: 0px; border: 0px; font-size: 13px; font-family: inherit; vertical-align: baseline; color: rgb(35, 121, 181); text-decoration: none; - Preprint: Recurrent Mutations in SARS-CoV-2 Genomes Isolated from Mink Point to Rapid Host-Adaptation).
But the concern is that as SARS-CoV-2 continues to evolve, it may `figure out' - through genetic trial and error - how to infect, and spread in previously poorly susceptible hosts.
Last month, in https://afludiary.blogspot.com/2021/02/eid-journal-sars-cov-2-exposure-in.html" style="margin: 0px; padding: 0px; border: 0px; font-size: 13px; font-family: inherit; vertical-align: baseline; color: rgb(35, 121, 181); text-decoration: none; - EID Journal: SARS-CoV-2 Exposure in Escaped Mink, Utah, USA , we looked at a seroprevalence study done on wildlife captured in and around two infected mink farms, looking for signs of spillover.
Testing was done on 102 mammals (78 rodents and 24 mesocarnivores). Rodent captures consisted of 45 deer mice (Peromyscus maniculatus), 5 Peromyscus spp. mice, 25 house mice (Mus musculus), and 3 rock squirrels (Otospermophilus variegatus).While none of the rodents was found
In line with previous findings that (non-transgenic old world) mice are not susceptible to the virus, the authors reported that :11 mink escapees tested positive for SARS-CoV-2 antibodies by virus neutralization ( https://wwwnc.cdc.gov/eid/article/27/3/20-4444-t1" style="margin: 0px; padding: 0px; border: 0px; font-size: 13px; font-family: Helvetica, Arial, Verdana, sans-serif; vertical-align: baseline; color: rgb(35, 121, 181); text-decoration: none; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); - Table ). No other animal had a detectable antibody response.
While reassuring, the bulk of these studies have been conducted on the 2020 `wild type' SARS-CoV-2, as emerging variants (B.1.1.7, B.1.351, & P.1) have only become prominent in the past few months.
All of which brings us to a new (preprint) study that - similar to yesterday's report - suggests some of these emerging variants may be getting better at adapting to non-human hosts.
I've only included the link, abstract, and some excerpts from a much longer (16-page PDF) report. Follow the link to read it in its entirety.
https://www.biorxiv.org/content/10.1101/2021.03.18.436013v1" style="margin: 0px; padding: 0px; border: 0px; font-size: 13px; font-family: inherit; vertical-align: baseline; color: rgb(35, 121, 181); text-decoration: none; - - The B1.351 and P.1 variants extend SARS-CoV-2 host range to mice
SARS-CoV-2 extensive circulation in humans has been associated with the emergence of variants, including variants of concern (VOCs) with diverse mutations in the spike and increased transmissibility or immune escape 2.
Here we show that unlike the initial virus, VOCs are able to infect common laboratory mice, replicating to high titers in the lungs.
This host range expansion is explained in part by the acquisition of changes at key positions of the receptor binding domain that enable binding to the mouse angiotensin-converting enzyme 2 (ACE2) cellular receptor, although differences between viral lineages suggest that other factors are involved in the capacity of SARS-CoV-2 VOCs to infect mice.
This abrogation of the species barrier raises the possibility of wild rodent secondary reservoirs and provides new experimental models to study disease pathophysiology and countermeasures.
(SNIP)
Main Text:
Host range expansion or switch to other species has been prevalent in the course of coronaviruses evolutionary history 3 . Understanding the host range and how it is modified as the pathogen evolves is critical to estimate the emergence risk and determine the reservoirs to monitor. In the case of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the ongoing coronavirus disease 2019 (COVID-19) pandemic, animals such as non-human primates, hamsters, ferrets, minks and cats were shown to be permissive 4 .
By contrast, the zoonotic virus was shown to not replicate in mice and rats due to poor binding of the virus spike on the rodent cellular receptor angiotensin-converting enzyme 2 (ACE2).
At the end of 2020, the emergence of variants of concern (VOC) was noted in different parts of the world. The lineage B.1.1.7 (Pango designation 5 , also named 20I/501Y.V1 or VOC202012/01) was noted for its rapid spread in the UK 6 , while lineage B.1.351 (20H/501Y.V2) expanded in multiple regions of South Africa 7 and the P.1 (20J/501Y.V3) lineage emerged in Manaus, Brazil 8 . The global circulation and spread of these variants have led to concerns about increased transmission and their potential to evade immunity elicited by vaccination or naturally acquired.
All three variants harbor the N501Y change in the spike glycoprotein which belongs to a set of 6 key amino acid residues critical for the tight interaction of the RBD with hACE2 9 . Strikingly, this mutation was also noted, among others, in independently generated mouse-adapted SARS-CoV-2 strains 10,11. Here, we assessed the replication potential in cells and in mice of low-passage clinical SARS-CoV-2 isolates of the main lineages.
(SNIP)
Finally, although the infectious dose and the transmissibility between mice remain to be established for these new variants, as well as the permissiveness of related animal species, these results raise major questions on the risk of mice or other rodents living in proximity to humans of becoming secondary reservoirs for SARS-CoV-2 in regions where the B.1.351, P.1 or other specific variants circulate, from where they could evolve separately and potentially spillback to humans.
Indeed, rodents have been hypothesized as the ancestral host of some betacoronaviruses (lineage A, which includes the seasonal human coronaviruses OC43 and HKU1 20,21). While rodent densities are highly variable and more difficult to control, similar and actionable concerns were raised upon the detection of SARS-CoV-2 in Mink farms in The Netherlands 22 and in Denmark 23 due to the density of animals housed, and the detection of changes in the virus genome.
We posit that host range should be closely monitored along the continued evolution of SARS-CoV-2.
https://www.biorxiv.org/content/10.1101/2021.03.18.436013v1.full.pdf" style="margin: 0px; padding: 0px; border: 0px; font-size: 13px; font-family: inherit; vertical-align: baseline; color: rgb(35, 121, 181); text-decoration: none; - Whether this apparent expansion of SARS-CoV-2's host range turns out to be merely a footnote in the evolutionary history of this pandemic virus - or rises to greater significance - remains to be seen.
It is, however, a reminder that with highly mutable viruses, we can't afford get too comfortable with their past behavior, as it can easily change over time.
https://afludiary.blogspot.com/2021/03/preprint-b1351-and-p1-variants-extend.html" style="margin: 0px; padding: 0px; border: 0px; font-size: 13px; font-family: inherit; vertical-align: baseline; color: rgb(35, 121, 181); text-decoration: none; - https://afludiary.blogspot.com/2021/...ts-extend.html
DJ-If Covid 19 did find new hosts that is very major ! Some of the recent changes in variants of Covid19 also show up in corona virusses infecting mice.
[url]https://www.npr.org/sections/goatsandsoda/2021/03/19/979314118/next-pandemic-scientists-fear-another-coronavirus-could-jump-from-animals-to-hum?t=1616332027926[/url] or https://www.npr.org/sections/goatsandsoda/2021/03/19/979314118/next-pandemic-scientists-fear-another-coronavirus-could-jump-from-animals-to-hum?t=1616332027926 - https://www.npr.org/sections/goatsandsoda/2021/03/19/979314118/next-pandemic-scientists-fear-another-coronavirus-could-jump-from-animals-to-hum?t=1616332027926 ;
Now, scientists are worried that another coronavirus will strike again, from either a bat or some other animal. So they've gone hunting for potential sources — and the news is a bit concerning.
"Coronaviruses are under our feet in rodents. They are above our heads in bats. We live in a kind of coronavirus world," says virologist https://www.sydney.edu.au/science/about/our-people/academic-staff/edward-holmes.html" style="box-sizing: border-box; -webkit-tap-highlight-color: transparent; margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(80, 118, 184); text-decoration: none; - Edward Holmes at the University of Sydney.
This past year, Holmes and his colleagues trapped several hundred bats in a tiny section of the Yunnan province in southern China — an area about the size of Los Angeles International Airport. They took samples of the bats' saliva, urine and feces. Then they looked for coronavirus genes inside the samples. What they found surprised him.
"So in this very small area that we sampled, about 1,100 hectare, there's an amazing number of bat viruses," says Holmes, who https://www.biorxiv.org/content/10.1101/2021.03.08.434390v1" style="box-sizing: border-box; -webkit-tap-highlight-color: transparent; margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(80, 118, 184); text-decoration: none; - reported the findings online last week.
Holmes and his team found that the bats harbored 24 new coronaviruses, including four closely related to the virus that causes COVID-19, or SARS-CoV-2, and three viruses closely related to SARS-CoV, which caused a smaller outbreak back in 2003.
On top of that, Holmes says, the bat species carrying these viruses are common across most of Southeast Asia. "So imagine if you ran our experiment across the whole of Southeast Asia. You'd find an amazing diversity of coronaviruses," Holmes says. "And there's just an enormous number of them."
And depending on how you define a virus species, Holmes says, there are likely thousands of different coronaviruses all around the world. "We're only just starting to scratch the surface," he says. "The virusphere of coronaviruses is just immense."
And these pathogens aren't just hanging out in bats. Many types of animals carry these viruses, including dogs, cats, birds, chickens, pigs and rodents.
Now the two big questions are: How often do these viruses jump from animals into people and how often do they make people sick?
Back in 2018, scientists at the nonprofit https://www.ecohealthalliance.org/" style="box-sizing: border-box; -webkit-tap-highlight-color: transparent; margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(80, 118, 184); text-decoration: none; - EcoHealth Alliance tried to answer that question in communities from southern China, including villages in the same province where Holmes trapped the bats. The team drew blood from about 400 people and looked for signs of coronavirus antibodies in their blood.
In one area, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178078/" style="box-sizing: border-box; -webkit-tap-highlight-color: transparent; margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(80, 118, 184); text-decoration: none; - they found that nearly 3% of people had been infected with an unknown coronavirus in the past few years. "That's pretty high," says Peter Daszak, who helped to lead the study.
If you expand those findings to all parts of Southeast Asia where people are exposed to these bats, Daszak estimates that more than a million people are infected with unknown coronaviruses each year.
In other words, new coronaviruses are constantly jumping from bats and other animals into people — a process scientists call "spillover."
"It's happening every day," Daszak says. "I look at the spillover event a bit like rain or snow. These viruses are getting into and trickling across our populations."
The vast majority of these spillover events do very little, he says. But each one gives the virus the opportunity to adapt and spread more easily from person to person. Every once in a while, a contagious virus infects a person who finds their way to a dense city, such as Wuhan.
Both Daszak and Edward Holmes agree: The next coronavirus outbreak could be right around the corner.
"I think we need to face reality here," Holmes says. "Coronavirus pandemics are not a once in a hundred year event. "The next one could come at any time. It could come in 50 years or in 10 years. Or it could be next year."
DJ-In a next phase we may not be able to find out if Covid19 did mutate/a new variant is spreading-or another corona virus jumped to humans. [url]https://www.bbc.com/news/science-environment-54918267[/url] or https://www.bbc.com/news/science-environment-54918267 - https://www.bbc.com/news/science-environment-54918267 mutated coronavirus may jump back and forth between animals
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We cannot solve our problems with the same thinking we used when we created them.
~Albert Einstein