Surveillance & Monitoring
The district monitors mosquito species, population levels, and disease presence throughout mosquito season (typically May – October). Tracking both density and disease is what we call surveillance — and it drives every treatment decision we make.
Larval Surveillance
Field technicians sample known and newly discovered breeding sites across the service area using a dipper — a long-handled cup that collects water samples for examination. Each sample is analyzed for:
- Abundance — how many mosquitoes are present
- Species — which mosquitoes are breeding there
- Life stage — larval or pupal
Results are compared against historical records to determine whether and how to treat.
Adult Surveillance
Adult mosquito traps are deployed twice weekly throughout the season. This serves two purposes:
- Finding new sources — adult activity often reveals undiscovered larval breeding sites
- Disease testing — live adult mosquitoes are collected and tested for West Nile virus, St. Louis encephalitis, and western equine encephalitis
Together, larval and adult surveillance give us a complete picture of where mosquitoes are, what species are present, and whether disease risk is elevated — before we act.
