https://www.nationalgeographic.com/animals/invertebrates/gro...
What does evolution “pressuring” mean? Either the organism (or virus) has sufficient chances to randomly mutate a a trait that enables it to survive, or it goes extinct.
Think of a population as holding at any given time a number of individuals carrying mutations. The fringe mutations, such as being able to be hosted by a different type of mosquito (say, better survivability in the host) don't provide much of a benefit to survival. But if the default host population goes away, those mutations become super valuable and will be selected.
See https://www.scientificamerican.com/article/transgenic-mosqui... for a discussion on this topic.
https://www.nature.com/articles/466432a
I think there's even an argument to be made that we should increase our risk tolerance relative to the scale of the harm, and if you study mosquitoes for even a little bit, the harm is off the charts. Fortunately ecologists pretty uniformly agree this is an easy case.
https://www.nature.com/articles/466432a
https://www.wnycstudios.org/podcasts/radiolab/articles/kill-...
So if we did eliminate mosquitoes, it's probably not going to be a clear win.