Merged 2019-nCoV / Corona virus

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Skeptic Ginger said:
Funny, other than mild differences, we don't see that happening. Care to cite a strain of seasonal flu that happened to that wasn't from a reassortment?


And no, your cites didn't say seasonal flu mutates to more severe cases. Your sources were about genetic changes in general, basic evolution we all know: selection pressures acting on random mutations.

Also, what are the selection pressures that act on seasonal flu to produce more virulent strains? You seem to have forgotten that half of the equation.
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In answer to your question the selective pressure to increase virulence is the development of (partial) immunity in the host population. Partially immune hosts will be less likely to be infected, with milder shorter lived disease and less viral shedding. Either mutations that suppress or evade the immune response or increase viral shedding, will favour continued viral circulation.

Back to you, what are the selective pressures to decrease virulence which you claim is what happens.

Transient virulence of emerging pathogens.
Bolker BM; Nanda A; Shah D.
Journal of the Royal Society Interface. 7(46):811-22, 2010 May 06.

Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution.
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This paper which looked at a number of viruses suggests virulence should increase during outbreaks.

Re-emergence of H3N2 strains carrying potential neutralizing mutations at the N-linked glycosylation site at the hemagglutinin head, post the 2009 H1N1 pandemic.
Ushirogawa H; Naito T; Tokunaga H; Tanaka T; Nakano T; Terada K; Ohuchi M; Saito M.
BMC Infectious Diseases. 16:380, 2016 08 08.
Abstract
Background
Seasonally prevalent H1N1 and H3N2 influenza A viruses have evolved by antigenic drift; this evolution has resulted in the acquisition of asparagine (N)-linked glycosylation sites (NGSs) in the globular head of hemagglutinin (HA), thereby affecting the antigenic and receptor-binding properties, as well as virulence. An epidemiological survey indicated that although the traditional seasonal H1N1 strain had disappeared, H3N2 became predominant again in the seasons (2010–11 and 2011–12) immediately following the H1N1 pandemic of 2009. Interestingly, although the 2009 pandemic H1N1 strain (H1N1pdm09) lacks additional NGSs, clinically isolated H3N2 strains obtained during these seasons gained N (Asn) residues at positions 45 and 144 of HA that forms additional NGSs.

Methods
To investigate whether these NGSs are associated with re-emergence of H3N2 within the subtype, we tested the effect of amino acid substitutions on neutralizing activity by using the antisera raised against H3N2 strains with or without additional NGSs. Furthermore, because the N residue at position 144 of HA was identified as the site of mismatch between the vaccine and epidemic strains of 2011–2012, we generated mutant viruses by reverse genetics and tested the functional importance of this particular NGS for antibody-mediated neutralization by intranasal inoculation of mice.

Results
The results indicated that amino acid substitution at residue 144 significantly affected neutralization activity, acting as an escape mutation.

Conclusions
Our data suggest that the newly acquired NGSs in the HA globular head may play an important role in the re-emergence of endemic seasonal H3N2 strain by aiding the escape from humoral immunity.
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This paper identifies a specific mechanism in circulating H3N2 to explain its re-emergence as it has gained increased resistance to humoral immunity, thus increasing its virulence and increasing its infectivity. There are other papers documenting similar gains in virulence in circulating strains.
 
Planigale said:
This paper which looked at a number of viruses suggests virulence should increase during outbreaks.
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If that happens with Covid-19, we'll be looking at 100 million dead and a global economic recession much worse the the Great Depression.

Sleep well.
 
Virus name is proposed as SARS-COV-2. Disease is COVID-19.


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The Atheist said:
If that happens with Covid-19, we'll be looking at 100 million dead and a global economic recession much worse the the Great Depression.

Sleep well.
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Or, in code, Hong Mei House (at Cheung Hong Estate) is the new Amoy Gardens. :D

Decoding somewhat: during the SARS epidemic, a somewhat unusual transmission path was identified when a hotspot in Amoy Gardens (Hong Kong) was investigated. A new, Covid-19, hotspot in Hong Mei House (also Hong Kong) may be similar.
 
Belz... said:
I don't know why you keep pushing the doomsday scenarios, here.
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Jesus H Christ, if you read the thread, you'd see that all the way through I've been hopeful it is kept under control, but facts are facts, and the fact is that if it gets out of control and retains or increases virulence it will be a worldwide disaster on a scale not seen since 1918/19.

Today's news is more encouragement - no major increases outside China, no more deaths outside China, and a big slowing of infections in China itself - but I'm not about to ignore the possibility it turns the other way.

Mate, my two best friends on the planet are directly in the line of fire if it gets out of control - one has heart disease and the other is undergoing chemo for non-Hodgkins Lymphoma.

If you want fairytales and happy stories, this forum is probably the wrong place to be, because it's supposed to be about facts and evidence. On one hand, a poster here is maintaining that influenza is thousands of times more dangerous than Covid-19, which is palpable nonsense, especially when WHO has released this:

"If the world doesn't want to wake up and consider the virus as public enemy number one, I don't think we will learn from our lessons," WHO chief Tedros Adhanom Ghebreyesus said in Geneva.
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https://www.aljazeera.com/news/2020...-outbreak-latest-updates-200211012218330.html

If the outbreak does become a global catastrophe, it's entirely possible that susceptible people could make plans to avoid it, and that involves a little planning now. Better to have a plan and not need it than wake up dead in intensive care.
 
Well Earth could do with few % of humans gone. Thing is, it won't be so easy. After crisis there is war. And these days, after war there is nothing.

But hey, my opinion about 'the end' is I'd like to see it.
 
Skeptic Ginger said:
Not everything has a dry surface. Lettuce, for example. By the time it's in your bag it has been touched by the grocer, clerk and the bagger.
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I hope everyone already washes their lettuce for bacterial reasons. I usually use soapy water followed by a rinse. Often I also discard the outer leaves because they are brown first.
 
I would like to think that it is possible to appropriately recognize a danger and respond to it as intelligently, effectively, and forcefully as possible and necessary. Panic, theories unrooted in facts, and carelessly propagating false information are not part of an intelligent and effective response. I am not aiming this at particular posters here, but rather the informational sphere "out there" as a whole. Even some established news agencies appear to have gone for the melodramatic click bait approach when reporting this epidemic vs responsible coverage.

Particularly in an epidemic claims and "information" should be carefully verified. Lots of frightened people making decisions on false information or unjustified extreme predictions makes epidemics worse, not better.
 
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Capsid said:
Virus name is proposed as SARS-COV-2. Disease is COVID-19.


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Since it doesn't cause "Severe Acute Respiratory Syndrome" the same way SARS did, did you see why they were considering SARS in the name?
 
Giordano said:
I hope everyone already washes their lettuce for bacterial reasons. I usually use soapy water followed by a rinse. Often I also discard the outer leaves because they are brown first.
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Of course. But this comes down to how infectious the pathogen is and whether rinsing the lettuce and peeling the outer layers off assures no virus goes from the bag and lettuce to your hands and your mouth.

Try it (before COV-19 gets here). Pretend a highly contagious pathogen is spreading in the community and see how hard it is to avoid every possible point of contact.

It's hard to do.

On the bright side, with good hand washing and avoiding other people's saliva like when sharing food, I haven contracted an upper respiratory infection in a couple decades despite my son bringing home URIs on a regular basis all through school and beyond.
 
Yep, working front office for doctors taught me a couple of important rules.

Wash your hands thoroughly and often, and even more important, don't touch your eyes, nose or mouth unless you have freshly washed hands. Sanitizer is better than nothing, but good handwashing and keeping my mitts away from my face kept me from getting everything the patients dragged in, and still protects me when I regularly travel on public transit. Even when it sounds like someone's hacking up a lung two seats back.
 
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