It appears to me, Noir was attempting to dispute my claim that viruses tend to get less virulent over time. He did so by pointing to two particularly deadly strains of virus that are exceptions to that claim while not realizing that there are over forty strains of that virus that are not deadly making those two statistical outliers. There are always exceptions.How about I put it more simply.
His next comment seems to sarcastically imply that a virus would act in it's own best interest. It won't. It can't. It doesn't know what it's interests are. It acts in the manner it was genetically programmed to. It will only change how it acts when it accidentally mutates again. Those mutations are random and produce organisms both better and more poorly suited to their environment. So yes, they will act in ways that are against their best interest. And they die out like the vast majority have throughout time.
Thirdly, viruses do evolve over time without a design, but the most successful ones trend towards being less virulent because it is a more efficient way to replicate in new hosts, as a sicker host is less mobile and and less able to spread the infection. Once the host dies the virus dies with it. (becomes inactive) Especially a virus that requires blood to blood contact for transmission. Nature rewards flexibility. That's why viruses have been around so long. They tend to spontaneously mutate a lot. Some survive, most do not.
If Noir is not trying to use the aids viruses to disprove my premise about viruses then I have misread his intent. He is free to clarify the point of his post. We'll see. Originally Posted by Ducbutter
Viruses don’t have a plan when they mutate. They just mutate, likely based on some cellular interaction when they replicate. There’s no plan to become less virulent or deadly or more easily spread.
Now what happens is that strains that spread easier do just that, spread faster. Strains that kill the host too quickly die our because they can’t spread because the host dies. Strains that take a long time to kill and spread easily get the best of both worlds. Just like strains that aren’t deadly and spread easily.
In any event, the virus itself doesn’t go about planning its future existence. However, environmental factors have a huge impact on what variant of a virus hangs around.