5 ms·

Any virologists here? Is it possible that we may have a grave future where a virus emerges with R0 value of 6-7 (such as measles virus), long incubation period

• phreeza 7y ago
  So could an asteroid impact, or Yellowstone volcano erruption, or thermonuclear war. The question is how likely is it.
  • rolph 7y ago
    it [pathogen] has happened already a number of times, the chance is not a marginal one, vs one little impact in russia that was witnessed,
    • ceejayoz 7y ago
      Asteroid impacts and supervolcanoes have "happened already a number of times". Certainly more than just "one little impact in Russia".
      • rolph 7y ago
        yes certainly but we havnt directly observed very many of them, and for most of them we were not even extant. the extension is that near earth objects are quite common but we dont notice a lot of them. just like disease epidemic or pandemic, a number of them have happened already we just are not good as a group at noticing those things probably due to preoccupation with little rectangles of paper with famous historical figures printed on them.
• perl4ever 7y ago
  (Not a virologist) As I recall, the virus in The Stand had a death rate of something like 99.4%. However, if that actually happened, it seems like there would still be enough people to make a medium sized country, and wouldn't it rapidly evolve to be less virulent anyway? But anyway, just on my vague sense of fate, this all might be an omen for what happens in ten or twenty years. I keep thinking of the 20th century kind of echoing, first there was WWI, the flu epidemic, the depression, WWII...early on you couldn't have imagined what was coming.
  • rolph 7y ago
    there is no directed selection like that. its a luck of the draw and then selection for most apt to produce offspring. the virus can become more lethal in effect over time, or take on troublesome characters such as asymptomatic contagion with extended incubation period. the virus is so problematic right now due to a sponteneous mutation altering its previous character.
    • perl4ever 7y ago
      What do you mean "there is no directed selection"? Any virus is reproducing as it spreads, so it seems to me impossible for there not to be evolution happening. Milder illness enhances the spread, so it's going to be selected for. What is the counterargument?
      • rolph 7y ago
        directed selection is not darwinist evolution and does not exist in accepted evolutionary theory. it is artificial selection. directional selection is a very different thing it exists, it is part of evolutionary theory, it means there is a bias toward a particular allele [natural selection is a form of directional selection. selection does not lead to a path of improvements, it leads to changes in frequencies of phenotypes. there are other ways of enhancing spread, and retaining lethality, such as being communicable before symptoms become debilitating, this removes selective pressure that is based on communicability. If the host does not get sick enough to to be bedridden, they can contact other hosts. If the symptoms are mild or unseen there is no behavioral basis for other hosts to avoid the infected host. so by delaying expression of characteristics the virus may be highly communicable and highly lethal at the same time. high lethality is not subject to selective pressure in this case and will remain.
• magicalhippo 7y ago
  Surely such death rates would surely make people a lot more scared, thus a lot more likely to maintain quarantine and isolation. And the governments wouldn't suggest silly things like keeping schools etc running like normal.
  • loopz 7y ago
    Running schools isn't silly if children don't get infected. However, the jury still out on that one, it seems prudent to not take chances on unknowns.
    • watwut 7y ago
      Children do get infected and can spread infection. They are significantly less likely to die and have very very mild symptoms. (Not mild as in official "anyone not in hospital" but mild as in "super easy").
• santoriv 7y ago
  Complete extinction of humans is a high bar. Also I would expect that the reaction to such a disease would be extreme. It could certainly be much worse than the current crisis we are facing.
• twomoretime 7y ago
  Why not? COVID19 is shaping up to have all of that except for the high death rate, though the rate as we're finding out is much higher than China let on, even in young people... Edit:
  • MikeAmelung 7y ago
    Did you create this account to cause panic? Complete bullshit statement you just made.
  • LandR 7y ago
    So why aren't other countries reporting deaths in young people? So far in Italy the death rate under 40 is tiny.
    • twomoretime 7y ago
      Some 50% of people in ICU are under 50. When ventilators run out you'll see the deaths rise.
  • paol 7y ago
    > much higher than China let on There's absolutely no indication of this. Please don't spread harmful misinformation.
    • twomoretime 7y ago
      >https://www.reddit.com/r/Coronavirus/comments/fmgs93/governor_cuomo_younger_people_listen_up_55_of_nys/ https://www.reddit.com/r/Coronavirus/comments/fmgs93/governo... Here's the latest reason you're wrong. It's a link to a tweet from the governor of NY. Same has been reported in multiple countries in Europe. When ventilators run out, even young people start dying. The death rate in Italy is already higher than 1-3%, especially if you calculate (num recovered)/(num recovered + num dead). There are dozens of reasons not to trust the Chinese numbers - statistically perfect (Reg coeff>.999) quadratic growth curve, claims of all being well while pollution maps showed nationwide shutdown, admonishment and disappearance of whistleblowers, including doctors, scientists, billionaire tycoons, and activists...it's all been floating around the internet since January. Little of it is picked up by "official" sources because when a government shuts down any unapproved media in a nation without free speech, people can only leak through channels like WeChat screenshots, tweets and Twitter videos. But the rationale makes sense in addition to the wealth of circumstantial and empirical evidence. An authoritarian, autocratic nation can only rule so long as the people are kept by respect and/or fear from revolting. That is why the CCP has a history of controlling narratives to save face. This is not unique to the CCP, which is an offshoot of the former CCCP which practiced the same manipulation for most of it's history. The CCP spent two critical months trying to hide this from the world, and now we are all going to pay for it. Do not let their propaganda machine set the narrative. This is not a reflection on the Chinese people, their hands are tied by a self-preserving bureaucracy.
• djdkrkfkgk 7y ago
  No need to speculate. Bird Flu (H5N1) has 50% mortality, and it's like a flu in other aspects. It's only a few mutations away from human to human transmission.
  • systemvoltage 7y ago
    I am truly alarmed and completely unqualified to say this but I'll throw it there anyways - I would vote for reducing military spending by 90% and increasing pandemic R&D, hygiene and medicine spending by 10000%. If a nation is nuclear armed, we don't need a massive military perhaps.
  • dogma1138 7y ago
    H5N1 doesn’t spread well it’s primarily only bodily fluids hence why we only had about 800 confirmed cases. It also doesn’t survive long at 37c or higher temps (6 days at 37c and drops fast from there). Birds have higher body temperatures which helps to regulate the virus so while they can be carriers they are usually asymptomatic since the virus can’t replicate fast enough to cause major issues.
• AtlasBarfed 7y ago
  Zombie movies are basically this, but with enough disruption everyone becomes desperate and would flee the cities looking anywhere for food. And when the supply disrupts, the most readily available supply will be ... other humans. The real danger would be if it stays in a host like bubonic plague, and even if you survive the direct human transmission, it still gets to you... Also, those death rates were supposedly what native americans suffered when exposed to european diseases.
• vanniv 7y ago
  With a virus such as that, perhaps we would actually be allowed to use the treatments that get developed, instead of being told to let people die because "we want to do more studies" forever
  • amalter 7y ago
    I'm not sure what country you're located in, but at least in the US, there is the "Expanded Access" program - otherwise known as compassionate use. (https://www.fda.gov/news-events/public-health-focus/expanded-access https://www.fda.gov/news-events/public-health-focus/expanded...) It was widely used during the HIV epidemic to provide pre-trial access to medications and my hypothesis is that the program will be used even more extensively for sars-cov-2. If your country does not have a law like this, now is the time to push your representatives. Note - this is different from allowing OTC access to chloroquine willy nilly. If that is the suggestion, I am in agreement with the government that physician mediated access is the wisest course. While we know the safety profile of the medication, the doesn't make is "safe".
    • vanniv 7y ago
      That's why in the US after the president ordered the FDA to approve Choloroquine for use against COVID, the FDA immediately came out and demanded that it not be used, except for "compassionate use" in the most severe cases (people who will die anyway, even with treatment), and in the UK why after studies started to appear showing it to be highly effective, the UK banned the sale of the drug. First rule of power: never waste a crisis. If we cure this thing now, before the destruction of all personal freedoms is complete, people won't be willing to go quietly into the totalitarian night. Therefore, it is critical that even news suggesting there might be a cure be suppressed. Notice how for every one article you can find about the promise of Cholorquine + Azithromycin, you'll find 10,000 all talking about how it's a hoax/lie/fabrication, or else that more study is needed -- at least another 12/18/36 months? All long enough to ensure that the dismantling of our society can be completed before anybody can be treated.
• dogma1138 7y ago
  Mortality and R0 will be inversely correlated viruses that excel at killing the host will be contained by the hosts dying rather than infecting many others. Also the natural selection on viruses would result in them evolving into less deadly forms because those would be the ones that get more wide spread. Other factors like long incubation and infectiousness are also often inversely correlated the incubation period is the time when the virus replicates while remaining mostly asymptomatic which often means for airborne viruses it’s also a period when the host isn’t particularly infectious.
  • ignoramous 7y ago
    What's the possibility of creating such a virus in a lab?
    • dogma1138 7y ago
      Fairly low while we can snip a few genes here and there the technology isn’t there. When it will be it can also be used to easily create a cure if you can assemble viruses like legos it would be also incredibly easy to create inhibitors and anti bodies with the same technology. This is also what we are doing atm basically playing a huge game of “Perfection” by trying to find anything that would fit one of the “holes” on the virus, our cells or those which open up during its assembly process like its viral protease.
    • pen2l 7y ago
      I fear that now that we have witnessed the economic turmoil it can inflict on any community where this virus is released, there are entities out there who have taken notice and will explore this as a means to future warfare.
      • sergiomattei 7y ago
        I believe it's the opposite now. This virus has shown the widespread economic impact and unpredictability that the uncontrolled spread of a virus can unleash on the world. After this, I'm sure no superpower will want to take a chance releasing a weaponized pathogen: it might just come bite them back in the ass.
• sbuttgereit 7y ago
  How many past events of rapid, steep population decline have we seen in the historical/archaeological record? Assuming that, historically speaking, travel isn't what it is today, I would expect such cases to be localized, but still I think it can go some distance to answering your question. We see instances of civilizations falling apart, but I'm certainly not aware of any where a top of your range disease was considered a reasonable possibility. Of those that come within your range, the only instances I can think of were in combination with other pressures... a large portion of the population gets very sick while at the same time the society comes under attack from outside peoples. How many times do we see this sort of thing in nature? We do see infestations, like beetles destroying forests, but I'm not so sure we have many cases where we expect viral infections to be the likely candidate. Of all the disease related scenarios I'm worried about, none match your scenario. I do think in some ways humans are "tuned" to apocalyptic thinking moreso than is perhaps is helpful. I think we're more prone to accept emotional arguments than we should be, causing us to possibly be more a danger to ourselves in the face of a terrible disease than the disease itself. I'm much more afraid of what we'll do to each other and ourselves, willingly, under pressure, than I am about even the most deadly viruses will do. Having said all of this: it's all opinion and none of it comes from expertise. Others may point out evidence to the contrary.
  • systemvoltage 7y ago
    Isn’t this is literally survivorship-bias? There are a lot of events that can happen in future which has no precedence. But I generally agree with you, it’s hard to speculate.
    • sbuttgereit 7y ago
      I don't think it is; assuming the questions of the original commentator asked can be read as a "how likely" sort of thing. I'm not saying look at the people here and you have your answer (aside from extinction level epidemics, which we can exclude because we are here), but complex life has existed for quite a while and even humans have on a relative basis. If the sort of thing the commentator is thinking is at all likely, it very well is likely to have happened before (assuming viruses more easily evolve than more complex lifeforms do). I'm saying that we should be able to learn from what isn't here, from what didn't survive... not from what did. When we look back at what didn't make it, I don't know of many (any) cases where we say that the sudden appearance of an extremely virulent pathogen likely did in this species or that civilization. This isn't to say its impossible, but unlikely... if you perform a historical study of random individuals that play the lottery, you'll find that it's just parting a sucker from their money... yet there is nonetheless usually a winner.
• avz 7y ago
  I recently attended a virology lecture where this question was asked. The answer was that this is very unlikely. In fact, the evolutionary direction of all known viruses is the opposite: from high towards low virulence. High virulence is observed in viruses which have recently jumped from one species to another and can be thought of as temporary maladaptation to the new species. As the virus adapts, the damage it does in the course of its reproduction process becomes less and less severe. Eventually, many viruses end up causing mild symptoms similar to the common cold, warts etc.
• ves 7y ago
  It’s untrue that natural selection always guides pathogens to be less lethal. This is covered in ch. 64-66 of Quammen’s “Spillover”, which covers a seminal paper by Anderson and May[0] considering the case of myxomatosis. Here’s some salient quotes: Laboratory experiments showed that all field strains produced lesions that provided sufficient virus for transmission to occur,” he wrote. But the strains of very high virulence (grades I and II) killed rabbits “so quickly that infectious lesions were only available for a few days.” The milder strains (grades IV and V) produced lesions that tended to heal quickly, he added—and then the payoff, “whereas strains of grade III virulence were highly infectious for the lifetime of the rabbits that died and for a much longer period in those that survived.” Grade III, at that point, was still killing around 67 percent of the rabbits it touched. Myxoma virus, thirty years after its introduction, had found this level of virulence—being pretty damn lethal—to maximize its transmission. It was still capable of killing most of the rabbits it infected, but capable also of assuring its own survival with a continuous chain of infections. The first rule of a successful parasite? Myxoma’s success in Australia suggests something different from that nugget of conventional wisdom I mentioned above. It’s not Don’t kill your host. It’s Don’t burn your bridges until after you’ve crossed them... ...they[Anderson and May] plotted a relationship between virulence and success. Their result was a model-generated prediction: Given this rate of transmission, given that rate of recovery, given those unrelated mortalities, then . . . an intermediate grade of virulence should come to predominate. Son of a gun, it matched what had happened. [0]: https://www.cambridge.org/core/journals/parasitology/article/coevolution-of-hosts-and-parasites/AD3B9037962266A448DF14786AB1D6F8 https://www.cambridge.org/core/journals/parasitology/article...
  • systemvoltage 7y ago
    This is horrific. I am gonna use this term "Don't burn your bridges until after you've cross them" to communicate that contagious incubation period is extremely dangerous and the reason why the current Coronavirus epidemic turned into a global pandemic. Thus, testing is by far the most important capability to have - it is a litmust test whether the pathogen is ready to build one of those bridges to cross.
  • rolph 7y ago
    basically the selection mechanism is about being able to make copies of yourself that can make copies this mean reproductive success. when you can make copies that make copies at a higher rate overall then all others competing along the same resource access, you have i higher frequency of copy than all others, that is differential reproductive success and is the foundation of neodarwinian models of evolution
• martingoodson 7y ago
  A wonderful book that answers this and many other questions is 'Evolutionary Dynamics: Exploring the Equations of Life' by Martin Nowak.