The first three months are critical because it is your best chance to keep it from spreading far enough that it becomes impossible to contain. And keeping it contained avoids giving it as much of a chance to develop mutations that allow it to spread easier.
Novel viruses don’t mutate any faster than established ones though. And have no drive to become more virulent. Which seemed to be what your were saying.
Influenza is an established virus and mutates all the time.
Yes, evolution works fast and crossing into a new host is going to see its common sorts of mutations selected for or against. Those mutations that allow better transmissibility will be selected for; those that do not will be selected against. Often viruses win against their brothers and sisters by being less virulent as mild illness aids in transmissibility.
Well that and the fact that newly emergent viruses may well change in characteristics as they become established in the new host. You asked for a cite, I gave you three. Why are you ignoring them?
You first sentence is almost my exact words from post #129.
And the second is absolutely not what I have said.
The point is, it’s not that newly emerging viruses are more likely to mutate in the new host species than an established virus.
It’s that their exact mechanism is not yet tested in the new host; essentially they have picked up whatever mutations are required to jump the species barrier and nothing more*, and are initially ill-suited to the new host.
It’s somewhat meaningless to say a newly emergent virus is weakly contagious given that they almost always are…at first. They need to gain additional mutations for the new host then we get to see the potential of this new strain of virus in that organism.
And that’s why, as I cited, SARS, Ebola, Nipah virus and others all acquired mutations that made them more contagious in their first few months after initial outbreak in humans.
- I learned something else from my first cite. The mutations required to jump a species barrier are often suboptimal in terms of a virus’ fitness for a given host organism. So one selection pressure having jumped a species barrier is to shed those mutations.
Yep. Virulence could usually be considered a bad thing for the virus.
Nonetheless it can happen as a side effect as a newly emerging virus adapts to a new host.
In fact, this is pretty much the root of most pathological viruses in humans. Most pathological viruses jumped from a species where they caused mild or no symptoms and were more severe in humans just due to some side effect of the difference in pathophysiology.
I’m not.
I’m discussing them.
Again, what you seemed to me to be saying, may not be what you meant by there being a “much greater chance of them mutating to become more contagious or more virulent than a virus that has been mutating alongside humans for hundreds of years.”
We seem to agree that there is no particular reason to expect a novel to human virus to become more virulent as it spreads through a human population, any more than an established virus has any chance to, and perhaps a bit less reason to expect such. To some degree evolutionary success for the virus is helped by decreased virulence as it adapts to the new host, shedding the features that make the new host more ill faster.
Coronaviruses have a high mutation rate and there are lots of human coronaviruses out there. None that have been around in humans as a host a long time have a high rate of serious morbidity or mortality … convergent evolution to the most successful strategy for the family.
I think I see the misconception here.
Because I am saying there is an increased chance of a newly emergent virus becoming virulent. Not because it is mutating more. Not because it “wants” to become virulent. But because what we mean by “adapting to the host” is different for an established virus versus newly-emerged virus.
An established virus in humans is well adapted to spreading within and between humans. The main selection pressure on it now is simply the human immune system and the antibodies that are currently effective against the virus.
For a newly-established virus, it’s not the same.
Firstly, it necessarily acquired genes that allowed it to jump a species barrier, and, as I said, these genes are not only not required but are often suboptimal for the purpose of spreading within a species, so there is a selection pressure to shed those genes – this already can impact how contagious and how virulent the virus is as a side effect.
Secondly there may well be a number of genes the virus has that are beneficial for living in civet cats or bats, but are a hinderence in humans; so there’s a selection pressure against those genes too, and changes to those genes can have knock-on effects as well.
As I say, we cannot look at a new virus in a species, see that it is poorly contagious and has characteristics X, and declare that there’s nothing to worry about.
Because newly emergent viruses almost always are poorly contagious at first, having just jumped a species barrier. And their characteristics usually change as they go through this initial stage to some characteristics Y.
Usually X and Y are similar, but we can be unlucky and Y is some extremely virulent pathophysiology.
Parody song Fight The Virus sung to Sound of Silence
Hello virus from Wuhan
Another problem’s here again
Because you see the contagion creeping
And the virus is indeed spreading
And the memory of SARS planted in my brain Still remains
We stand and fight the virus
We hear of theories how it grew
From snakes and bats became a flu
Passing the sickness from man to man Now it’s growing, getting out of hand
It’s a virus that has travelled near and far Corona
We have to fight the virus
A bit depressing.
When you said Fight The Virus I immediately imagined “Public Enemy - Fight the Power” but with the lyric changed to Fight Corona. 
Russia closed their border today: Europe evacuates citizens from China, Russia shuts border | AP News
Per the Johns Hopkins site that blue infinity initially linked to. As of 1/30/2020 21:30 Eastern US time;
9776 cases
213 deaths (still all in China I believe)
Has anyone here heard of Fah Talai Jone? This medicinal herb is available from Amazon, seems definitely good at fighting virus, and is touted for other purposes as well!
Our sister tells us to take it as protection from the coronavirus. Google News doesn’t know about that yet — I get zero hits from “Fah Talai Jone coronavirus” but, as Hamlet said to Horatio, “There are more things in heaven and earth, Google, Than are dreamt of in your philosophy.”
I’m sure I’ll be laughed at here but, since Google tells me Fah Talai Jone may also prevent angina, I’ll be taking it. The Fah Talai Jone plants in our orchard are dying (S.E. Asia is in record-setting drought), but my wife just stopped at a drugstore and picked up 18 bottles!
ETA: Oops. I just clicked Amazon: "Currently unavailable.
We don’t know when or if this item will be back in stock. "
So… that’s a death rate of 2.2%, down from the initial 3%
Of course, many caveats with that - whether or not all infections are being captured in the data, in many cases the infections are new and it’s not known how serious they’ll become, etc., etc. but that’s the direction I’d like that stat to go. Also consistent that initially it was the most severe cases seen and now we’re capturing less severe instances of the virus.
Still spreading fast, though. Hope the containment measures being taken work.
I’m looking at a current headline that reads, “As the coronavirus spreads, fear is fueling racism and xenophobia”. Here is the link:
http://www.kake.com/story/41635356/as-the-coronavirus-spreads-fear-is-fueling-racism-and-xenophobia
Diaspora communities and local authorities are preparing for this, with many trying to calm fear before it becomes hysteria. In France, the newspaper controversy sparked a social media campaign, with many French Chinese citizens using the hashtag #JeNeSuisPasUnVirus – I am not a virus.
I saw in the news that some Chinese people living in Europe are actually carrying signs saying, “I am not a virus”. Reminds me of the tragedy in France that sparked many people to proclaim, “I am not Charlie”. That had something to do with the events of Jan. 7, 2015 concerning the newspaper “Charlie Hebdo” in Paris. For anyone who might suspect I chose the name “Charlie” in response to that, I chose this name long before that incident.
Some of you have advised me in private messages to try and relax and there is no reason to panic. I appreciate your kind words and thank you very much. Best wishes to you all.
In response to the Charlie Hebdo attack, people were declaring “I am Charlie,” not “I am not Charlie.” Clearly the “I am not a virus” shirts are related, but they declare a kind of opposing sentiment; the wearer is declaring no connection with the virus, whereas people claiming “I am Charlie” were declaring unity with (and support for) the victims of the Charlie Hebdo attack.
Go ahead and stock up on Forsythia instead.
Kind of surprising that the rate of increase of diagnosed cases has been so consistent. (Graph on the site above.) If only by virtue of wider deployment of testing capability and very high index of suspicion I would have expected the curve to be getting significantly steeper at this point. Instead the curve of diagnosed cases is merely a pretty straight line with the calculated mortality rate nevertheless decreasing. Huh. To me that reads like pretty dang effective containment and kudos deserved by the Chinese health system in particular.
Good article (and sad situation).
Another recent episode was a cruise ship of 6000 people in Italy that was quarantined because a Chinese woman had a fever (story).
OK she had come from Hong Kong, so it was a non-zero risk, but still.
On the topic of Chinese eating weird stuff, as well as the good points the article mentions (that few Chinese eat these exotic meats, and it’s all culturally relative anyway), one thing I’d add is this: the only reason eating cows or chickens doesn’t give us novel viruses is because we have already caught most of them centuries ago
(although new pathogens still occasionally occur e.g. CJD), and live and die with them already.
There’s a fundamental flaw in your reasoning here. We’re not necessarily concerned about what virulence phenotype is ultimately adaptive under natural selection for the virus, we’re concerned about the probability that mutations give rise to a virulence phenotype in the first place, and how many humans that might kill. Evolutionary adaptation by natural selection occurs through differential surivival of different phenotypes, in other words differential death. A mutation that gives rise to an “extreme virulence” phenotype for the virus may ultimately be an evolutionary dead end for the virus, because it kills the host much too quickly, and the virus requires hosts to remain alive. But it’s not much consolation if this process of natural selection for the non-virulent phenotype involves the death of 100 million humans!
Well first of all, no. Differential viral “death” rate is not what determines how much a virus spreads or kills.
The point your are responding to is a very narrow one: are novel to humans viruses MORE likely to become more virulent in the near future after having crossed species than ones that have been in humans for a long while?
And the answer is very clearly NO. The selection pressure is greater on a novel to human virus to keeping hosts not only alive but out and about functioning in society. Balanced with having a high enough replication within the infected individual to be spraying some out there (which means a bit sick).
Yes it is very true that a virus with a fairly low mortality rate that infects millions will still cause hundreds of thousands of deaths - see seasonal influenza. And yes to the point that a pandemic with high absolute numbers of deaths is possible while that selection process occurs - see Spanish flu. But this is where the high mutation rate of coronaviruses plays both ways - there is a greater chance that it will mutate to a more “successful” less virulent form faster than a new influenza one. Harder to contain but less likely as virulent if it spreads. Still correct during that race with many infected many could die as the mortality rate drops from 2% to orders of magnitude less.
FYI here is an interesting bit discussing mutations in novel to human viruses.