The theory goes : plagues that are especially deadly must spread through the body extremely quickly. Otherwise, they give the immune system time for the B cells to formulate an antibody. Yet, if the plague spreads quickly, it has a short incubation period, and it means that hosts will die before spreading it. Ebola is thought to fit in this part of the ecology, and this is one reason why the virus is rare.
A virus that spread itself like the flu but also killed like ebola would be pushed by evolution away from these properties because it would kill off it’s hosts too quickly.
Another factor is that some of the better viruses for evading the immune system (HIV) depend on being able to randomly recombine and change the pattern for their outer shells.
If you designed a virus that had a tough outer coating, targeted cells and receptors designed to kill the host, and had some kind of sophisticated clock mechanism to force a long incubation period, you would be forced to give it genes that would code for complex error correcting proteins so that each new generation of the virus would have a low chance of containing a mutation. This would in turn prevent it from evolving, allowing the immune system (and synthetic antibodies) to target it easily.
So, you’d have to deliberately make it able to adjust it’s own outer coat randomly, but not any other components.
Such a virus is not something evolution is likely to ever create (because for one, it would extinct it’s hosts, and for another, evolution doesn’t work like this. Evolution as an algorithm finds the highest point on the NEAREST hill in the solution space, not the peak of a theoretical mountain that towers over the solution space)
Net result : with very sophisticated bioscience, such a person killer that had overlapping qualities could be created. However, you are correct that there is a reason you don’t see them in nature.
Such a virus is not something evolution is likely to ever create (because for one, it would extinct it’s hosts
This is a reason we would not expect to see many of them around at any given time. But a virus that can extinguish its hosts has no pressure to avoid evolving that way in the first place. Neither viruses nor evolution can predict the future, at all.
This isn’t true. Viruses are subject to evolutionary pressure even inside a single patient. They don’t replicate perfectly (partly because they have to be small and simple, and don’t have very good control of the cellular environment they are inside, being invaders and all) and so variants of the particle compete with one another. Because of this, features that might be desired in a bioweapon but are not needed in order for the virus to replicate can get lost.
For instance, a bioweapon virus might contain genes for botulism toxin in order to kill the host. However, copying this gene every generation would diminish the particles ability to replicate, and so variants of the particle that are missing the gene would have a small evolutionary advantage. After just a few patients, the wild version of the virus might have lost this feature.
Very interesting, thanks for taking the time to give a detailed reply.
with very sophisticated bioscience, such a person killer that had overlapping qualities could be created.
How sophisticated are we talking? Is this something conceivable for sufficiently motivated modern day humans with access to up to date knowledge, or theoretically possible but extremely difficult?
The latter. I’ve read of limited successes in other fields of research (no one is publicly trying to make something like this) that indicate it’s just barely possible, maybe, with some luck.
One nasty thing is that the virus doesn’t have to be safe. It just has to work, and it’s not a problem if it permanently damages the people it doesn’t kill. So, creating a weapon like this is fundamentally much easier than trying to create, say, a treatment for cancer using similar methods.
The theory goes : plagues that are especially deadly must spread through the body extremely quickly. Otherwise, they give the immune system time for the B cells to formulate an antibody. Yet, if the plague spreads quickly, it has a short incubation period, and it means that hosts will die before spreading it. Ebola is thought to fit in this part of the ecology, and this is one reason why the virus is rare.
A virus that spread itself like the flu but also killed like ebola would be pushed by evolution away from these properties because it would kill off it’s hosts too quickly.
Another factor is that some of the better viruses for evading the immune system (HIV) depend on being able to randomly recombine and change the pattern for their outer shells.
If you designed a virus that had a tough outer coating, targeted cells and receptors designed to kill the host, and had some kind of sophisticated clock mechanism to force a long incubation period, you would be forced to give it genes that would code for complex error correcting proteins so that each new generation of the virus would have a low chance of containing a mutation. This would in turn prevent it from evolving, allowing the immune system (and synthetic antibodies) to target it easily.
So, you’d have to deliberately make it able to adjust it’s own outer coat randomly, but not any other components.
Such a virus is not something evolution is likely to ever create (because for one, it would extinct it’s hosts, and for another, evolution doesn’t work like this. Evolution as an algorithm finds the highest point on the NEAREST hill in the solution space, not the peak of a theoretical mountain that towers over the solution space)
Net result : with very sophisticated bioscience, such a person killer that had overlapping qualities could be created. However, you are correct that there is a reason you don’t see them in nature.
This is a reason we would not expect to see many of them around at any given time. But a virus that can extinguish its hosts has no pressure to avoid evolving that way in the first place. Neither viruses nor evolution can predict the future, at all.
This isn’t true. Viruses are subject to evolutionary pressure even inside a single patient. They don’t replicate perfectly (partly because they have to be small and simple, and don’t have very good control of the cellular environment they are inside, being invaders and all) and so variants of the particle compete with one another. Because of this, features that might be desired in a bioweapon but are not needed in order for the virus to replicate can get lost.
For instance, a bioweapon virus might contain genes for botulism toxin in order to kill the host. However, copying this gene every generation would diminish the particles ability to replicate, and so variants of the particle that are missing the gene would have a small evolutionary advantage. After just a few patients, the wild version of the virus might have lost this feature.
Very interesting, thanks for taking the time to give a detailed reply.
How sophisticated are we talking? Is this something conceivable for sufficiently motivated modern day humans with access to up to date knowledge, or theoretically possible but extremely difficult?
The latter. I’ve read of limited successes in other fields of research (no one is publicly trying to make something like this) that indicate it’s just barely possible, maybe, with some luck.
One nasty thing is that the virus doesn’t have to be safe. It just has to work, and it’s not a problem if it permanently damages the people it doesn’t kill. So, creating a weapon like this is fundamentally much easier than trying to create, say, a treatment for cancer using similar methods.