"Mosquitoes and ticks and the germs they spread are increasing in number and moving into new areas." Why? I suspect that climate change is a factor, but how do

"Mosquitoes and ticks and the germs they spread are increasing in number and moving into new areas." Why? I suspect that climate change is a factor, but how do we know whether that's true and the CDC isn't allowed to report it, or whether it's false?