Canada

There's not much you can do personally other than avoiding mosquito-prone areas and wearing proper clothing.

Municipalities and other governing bodies can implement mosquito control programs though if residents feel they would benefit from reducing the mosquito populations. WNv isn't a huge threat in Canada yet, it's much more prevalent in the United states, so most mosquito programs up here are to control them for nuisance for more enjoyable summers, tourism and business, outdoor labourers and farmworkers, etc.

I work in mosquito control and it's a pretty safe product that's used, no aerial spraying of chemicals in our area it's just targeting the larval stage of mosquitos by applying a bacteria which kills pretty much only mosquitos or black flies. Leaves everything else untouched.

Places like roadside catch basins can produce a lot of the mosquitos that transmit WNv, just sampled a townhome complex the other week and found that pretty much every one of their 30 catch basins were producing over 1000 mosquitos, likely on a weekly basis for months.

If you feel a mosquito control program is needed residents need to contact their municipal or regional representatives to get the process started. You may already have one going as well, where you may be able to get any stagnant water on your property treated for free (depending on the program). A lot of people don't even know their city has a mosquito control program, even ones which have been going for 20+ years.