West Nile Virus Threat Levels
Level 1: Remote Risk of Human Infections
- No positive surveillance indicators currently found in the county.
- Mosquitoes are starting to emerge in the spring.
Level 2: Low Risk of Human Infections
- First evidence of virus activity has been detected in Canyon County or the neighboring counties. Non-human surveillance indicators (mosquitoes, birds, horses, etc.)
Level 3: Moderate to High Risk of Human Infections
- Increase in WNV-positive surveillance indicators in Canyon County.
- Large or significant increase in Culex species mosquito populations.
- Large of significant increase in the number of infected mosquito pools (i.e. rising minimum infection rates.
- First human case detected in Canyon County or neighboring county.
Level 4: Human Infections In Progress
- Multiple human cases occurring in Canyon County and the surrounding counties suggesting an epidemic level activity.
- Ongoing evidence of WNV in other surveillance indicators (birds, horses, mosquitoes, etc.).
Level 5: Human Infections In Decline
- Late season, mosquito activity declining.
- Rate of new human and animal case reports declining.