I am also wondering how mosquito populations are affected by increasing human populations. I can imagine with a lot of left out garbage collecting standing water plus being a food source could have given mosquitoes a unnatural advantage.
Mosquitoes are prevalent even in super clean places, btw. I used to live by a small creek in Austin, TX and in the summers I could basically never enjoy my yard: it would be flooded by mosquitoes (the creek would have standing water which mosquitoes require to reproduce).