Interesting Mosquito Facts …
1) Did you know that human WNV risk increases and is often highest in August because the percentage of WNV positive mosquitoes is highest as the season progresses. This is because the mosquitoes have fed multiple times and the chance that they have fed from a WNV infected bird has increased.
2) In addition to WNV testing, we also test mosquitoes for other diseases, such as Eastern Equine Encephalitis virus (EEEv).

A good general WNV link to answer all your questions:
https://www.canada.ca/en/public-health/services/diseases/west-nile-virus.html
Links to Public Education and Risk Reduction Resource information:
https://www.canada.ca/en/public-health/services/diseases/west-nile-virus/prevention-west-nile-virus.html