I live in Arizona too. As you know we have a very limited mosquito season. Honestly I don't remember mosquitoes here AT ALL until after 1980s.
I think it depends on elevation and vegetation as well as the number of hours of sunlight. Another variable is likely temp of any standing water, which of course is related to the previously mentioned variables.
For example, I visit Alamo lake and even though there is a lake, I don't see any mosquitoes there ever. However, during the monsoon season, if we have one, the high country seems to have plenty.
I live between Holbrook and Zuni, NM, And only when the nights cool off in late summer have I seen mosquitoes. They are rare enough here my vet advised against inoculating my dogs against heartworm., Also spread by mosquitoes. Reason being is the meds are not great for dogs, admittedly better than heartworm, but since the risk is low..... Where I live erlichia is more common than heartworm, spread by deer ticks. Hell, I had that.( A month on Cipro is not fun buddy. )
My point in my first posts, was simply this:
A disease that requires mosquitoes to spread is seasonal, and as with the similar diseases(Zika, equine encephalitis, chinka sickness) is easy to control.
If WHO wants to spread fear porn, there are other diseases that are more serious and are communicable between humans(and animals).
Maybe they are coming out with a new vaccine of some sort and are trying to sell some.