2 ms·

Truly deadly virus's don't kill a lot of people. Evolutionally speaking, it's not to their advantage to do so. Take Ebola (a well known virus, with very high m

Truly deadly virus's don't kill a lot of people. Evolutionally speaking, it's not to their advantage to do so. Take Ebola (a well known virus, with very high mortality). It's very hard for Ebola to spread. It tends to make people obviously sick, and also kills quick, both of which make it much much easier to control. I'm guessing you don't spend a lot of time or energy avoiding Ebola. Contrast to AIDS, which did not make people sick, and so was easier to catch from a seemingly healthy person. From an AIDS perspective weakening the immune system against other diseases was a flaw in the plan. Once it became rampant though there were (and are) behavioral changes to reduce the chance of infection. Those behaviors are now "normal" because, well, AIDS. The "common cold" / flu etc are all covid, or covid-like viruses that constantly mutate and constantly do the rounds. We develop immunity over time and they mutate into milder (but more infectious) versions. We take steps to avoid these, but meh, if you get it you get it. Some behaviors from this pandemic will remain (stop letting - or worse requiring - obviously sick people come to work for example) - others will fall away (I don't see the mask thing sticking around forever...) We'll probably work from home more than we did before, but that was already a trend, this has just accelerated it. Even when we get back to normal I don't think I'll be flying to a city for random meetings anymore.

jacquesm 5y ago
But HIV/AIDS does kill a lot of people.
- bruce511 5y ago
  Technically it doesn't - people don't die Of Aids they die With Aids. But that's semantics. The point is that Aids has a long time between infection and death, thus encouraging spread.
  - jacquesm 5y ago
    Which is why you can't say that "Truly deadly virus's don't kill a lot of people." They can, and they do, there are many examples besides HIV.
    - bruce511 5y ago
      Yes, my original statement was incomplete. More accurately I should have said that truely deadly viruses don't kill people _quickly_. Ebola for example gets you sick, and you die quickly. This results in it not spreading well. AIDS kills you very slowly (over multiple years) so it has lots of time to spread (fortunately for us it's hard to catch). So the perfect virus would have the transmisabilty of Omicron, but with no symptoms for years - then by the time the first person dies we all have it already. Fortunately we haven't seen that one yet (in my lifetime anyway) and to some extent worrying about it is fruitless because there will be pretty much nothing we can do about it. You may as well be worried about every other ELE - asteroids, alien invasions etc.
heavyset_go 5y ago
> Evolutionally speaking, it's not to their advantage to do so. There are no goals, paths or planning in evolution, evolution is the result of chance. Selection pressures are what keep the effects of genetic mutation in check. The selection pressure that might cause a virus to become weaker is the result of the virus literally dying in all of the corpses it creates, while weaker strains potentially live on in the hosts they didn't kill. People aren't dying in droves because of COVID, so that selection pressure doesn't exist, and the virus is free to mutate into more virulent forms. Also, evolutionary timelines span many, many human lifetimes. In that time, a virus could very well become more fatal, wipe out entire species and die off itself like the majority of species in the history of the Earth, or it could become endemic in a different species afterwards and live on.
- bruce511 5y ago
  It's obviously mutating all the time. But if a particularly lethal version mutated into being it would quickly kill the host, thus not spreading far, if at all. Thus natural selection optimises for forms that spread but don't kill.
  - Xylakant 5y ago
    > Thus natural selection optimises for forms that spread but don't kill. It may also find an unlucky local optimum where it shows no symptoms for a period while already being highly transmissible and then slowly kill or leave the survivors with permanent damage.
    - bruce511 5y ago
      This is part of why AIDS is so bad. We're just lucky that AIDS is hard to catch outside of well understood behaviours. Mix AIDS with Omicron and you can stop bothering to save a pension.
  - jacquesm 5y ago
    This is simply incorrect. There are plenty of viruses that end up with an intermediary grade that may well have very high lethality. Once a virus has spread what happens to the host is irrelevant, including death. See May and Anderson's paper from 1982: Coevolution Of Hosts and Parasites. https://www.researchgate.net/publication/224043344_Coevolution_Of_Hosts_and_Parasites https://www.researchgate.net/publication/224043344_Coevoluti... DOI:10.1017/S0031182000055360
Xylakant 5y ago
> Truly deadly virus's don't kill a lot of people. Evolutionally speaking, it's not to their advantage to do so The Black Death (1) and the Spanish Flu would like to have a word. Humans eventually evolved sufficient immunity to defend against the pathogen, but significant proportions of the population died before that happened. (1) not a virus, IIRC, but the same evolutionary pressures should apply
- bruce511 5y ago
  I'm not a doctor but I belive the Black Death is bubonic plague, a bacterium. While yes that will evolve as well, the natural selection on bacteria happens on a very different time scale to a virus. And hoping not to start a thread on antibiotics and superbugs, but bacteria do naturally select as well. The Spanish Flu followed a similar path to Covid, it started deadly but then naturally selected to become less deadly. Its also somewhat unusual because of the numbers of displaced persons at the time returning home, the lack of basic medical knowledge etc. But here's my point. The Spanish flu has mutated now to be basically Flu. It's not "deadly" anymore (for some definition of deadly). Non deadly mutations naturally select over deadly mutations.
- arghnoname 5y ago
  It would depend on method of transmission. Bubonic plague was spread by rats. The hosts could be very ill or even dead; it didn’t matter. Respiratory viruses that only or mainly have human hosts need ambulatory vectors.
  - Xylakant 5y ago
    Corona has other hosts, some of which seem to be unaffected by it.

jacquesm 5y ago

But HIV/AIDS does kill a lot of people.

bruce511 5y ago
Technically it doesn't - people don't die Of Aids they die With Aids. But that's semantics. The point is that Aids has a long time between infection and death, thus encouraging spread.
- jacquesm 5y ago
  Which is why you can't say that "Truly deadly virus's don't kill a lot of people." They can, and they do, there are many examples besides HIV.
  - bruce511 5y ago
    Yes, my original statement was incomplete. More accurately I should have said that truely deadly viruses don't kill people _quickly_. Ebola for example gets you sick, and you die quickly. This results in it not spreading well. AIDS kills you very slowly (over multiple years) so it has lots of time to spread (fortunately for us it's hard to catch). So the perfect virus would have the transmisabilty of Omicron, but with no symptoms for years - then by the time the first person dies we all have it already. Fortunately we haven't seen that one yet (in my lifetime anyway) and to some extent worrying about it is fruitless because there will be pretty much nothing we can do about it. You may as well be worried about every other ELE - asteroids, alien invasions etc.

heavyset_go 5y ago

> Evolutionally speaking, it's not to their advantage to do so. There are no goals, paths or planning in evolution, evolution is the result of chance. Selection pressures are what keep the effects of genetic mutation in check. The selection pressure that might cause a virus to become weaker is the result of the virus literally dying in all of the corpses it creates, while weaker strains potentially live on in the hosts they didn't kill. People aren't dying in droves because of COVID, so that selection pressure doesn't exist, and the virus is free to mutate into more virulent forms. Also, evolutionary timelines span many, many human lifetimes. In that time, a virus could very well become more fatal, wipe out entire species and die off itself like the majority of species in the history of the Earth, or it could become endemic in a different species afterwards and live on.

bruce511 5y ago
It's obviously mutating all the time. But if a particularly lethal version mutated into being it would quickly kill the host, thus not spreading far, if at all. Thus natural selection optimises for forms that spread but don't kill.
- Xylakant 5y ago
  > Thus natural selection optimises for forms that spread but don't kill. It may also find an unlucky local optimum where it shows no symptoms for a period while already being highly transmissible and then slowly kill or leave the survivors with permanent damage.
  - bruce511 5y ago
    This is part of why AIDS is so bad. We're just lucky that AIDS is hard to catch outside of well understood behaviours. Mix AIDS with Omicron and you can stop bothering to save a pension.
- jacquesm 5y ago
  This is simply incorrect. There are plenty of viruses that end up with an intermediary grade that may well have very high lethality. Once a virus has spread what happens to the host is irrelevant, including death. See May and Anderson's paper from 1982: Coevolution Of Hosts and Parasites. https://www.researchgate.net/publication/224043344_Coevolution_Of_Hosts_and_Parasites https://www.researchgate.net/publication/224043344_Coevoluti... DOI:10.1017/S0031182000055360

Xylakant 5y ago

> Truly deadly virus's don't kill a lot of people. Evolutionally speaking, it's not to their advantage to do so The Black Death (1) and the Spanish Flu would like to have a word. Humans eventually evolved sufficient immunity to defend against the pathogen, but significant proportions of the population died before that happened. (1) not a virus, IIRC, but the same evolutionary pressures should apply

bruce511 5y ago
I'm not a doctor but I belive the Black Death is bubonic plague, a bacterium. While yes that will evolve as well, the natural selection on bacteria happens on a very different time scale to a virus. And hoping not to start a thread on antibiotics and superbugs, but bacteria do naturally select as well. The Spanish Flu followed a similar path to Covid, it started deadly but then naturally selected to become less deadly. Its also somewhat unusual because of the numbers of displaced persons at the time returning home, the lack of basic medical knowledge etc. But here's my point. The Spanish flu has mutated now to be basically Flu. It's not "deadly" anymore (for some definition of deadly). Non deadly mutations naturally select over deadly mutations.
arghnoname 5y ago
It would depend on method of transmission. Bubonic plague was spread by rats. The hosts could be very ill or even dead; it didn’t matter. Respiratory viruses that only or mainly have human hosts need ambulatory vectors.
- Xylakant 5y ago
  Corona has other hosts, some of which seem to be unaffected by it.