Vector Index Log
The vector index tell us the relative risk of West Nile virus transmission. The vector index is based on the:
- Total number of Culex Pipien and Culex Tarsalis – the species that carry West Nile virus
- Number of infected mosquitoes across an area. The vector index is calculated by determining the average number of infected mosquitoes collected per trap in an area.
- Emergency spraying may be recommended when the vector index is at 0.75 or higher.