As usual, you define why you were never a molecular biologist. Try defining your terms a bit more succinctly. A virus does not 'take over' the host organism. A bit less Hollywood movie and a bit more biology would be helpful.That makes no sense. The mutation of a virus is often the result of stimulus from the host. The resulting strain is not necessarily stronger or weaker but has adapted to external conditions.Everything has a limit to adapting and everytime it mutates it can get stronger but eventually the mutations will make the virus weaker.
Remarkably, you explicitly define one of the basic principles of evolution, yet you can't allow yourself the intellectual integrity to admit that. To do so would immediately thrust you into a contradiction with your alleged supernatural realms where everything is reduced to the slogan, "the gawds did it".
Hollie as usual you are so wrong. The virus takes over the host organism and that is what leads to the virus mutating and it can become stronger or weaker but over time the mutations will have an adverse reaction on both the organism and virus.