West Nile Virus Data

2022 West Nile Virus Activiy

The map and table indicate where West Nile virus activity is occurring in Washington state. Human cases are shown by county where the infected person was most likely exposed to the virus and by county where the infected person lives.

Ongoing West Nile virus monitoring for infected dead birds and mosquitoes is limited to a few counties due to lack of resources. West Nile virus activity may not be indicated in your county, however, it's likely to be widespread in our state.

Follow these easy prevention steps to protect yourself and family.

Interested when new West Nile virus activity happens? Click to subscribe

2021 West Nile Virus Activity Map

2019 West Nile Virus Activity
West Nile Virus-Positive Cases in Washington, 2022
County   Human  Horse/Other Mammal    Bird    Mosquito Sample  
By County of Likely Exposure  By County of Residence 
Benton 0 0 0 0 3
Multi-county Exposure* 0 0      
In-state Acquired 0 0      
Out-of-state Acquired 0 0      
Total 0 0 0 0 3

Maps and statistics are updated daily by 3 PM. This table shows cases of West Nile virus reported in the state.

* "Multi-county Exposure" represents human cases that had potential exposure in more than one county.


Past West Nile Virus Activity

Final annual West Nile virus surveillance maps and statistics for 2002-2021

Find more surveillance data

The Washington Tracking Network presents 2006-2021 vector mosquito species, Culex pipiens and Cx. tarsalis, test data by county. It also shows bird and mammal test data. View data in a table, chart, and map format and export data for your own use.

See Washington Tracking Network - mosquito samples, birds, and mammals tested for West Nile virus.

National Surveillance Maps & Statistics

CDC West Nile Virus Statistics & Maps

West Nile virus surveillance data and maps on human infections and activity by state.

More Information