A horse in Yakima County has tested positive for West Nile virus, marking the first confirmed case of the virus in a horse in Washington this year. The Washington State Department of Agriculture (WSDA) announced that the 1-year-old thoroughbred exhibited neurologic symptoms before testing positive on September 11 at the Washington Animal Disease Diagnostic Laboratory.
This detection follows reports from the Washington State Department of Health (DOH), which recently identified positive mosquito pools carrying West Nile virus in Benton, Grant, and Yakima counties. These findings were made with help from local mosquito control districts and health partners.
The WSDA advises animal owners to take preventive measures. These include contacting veterinarians about vaccinating horses against West Nile virus and other diseases spread by mosquitoes, keeping livestock indoors or sheltered during periods when mosquitoes are most active—typically from dusk to dawn—and removing standing water where mosquitoes can breed. If it is not possible to remove water sources, they should be covered or refreshed at least twice weekly. The use of insect repellents approved for specific animal species is also recommended.
“Contact a veterinarian about vaccinating horses against WNV and other mosquito-borne diseases.
Place livestock in barns or sheltered areas with fans during peak mosquito activity (dusk to dawn).
Eliminate standing water where mosquitoes can breed. If emptying is not possible, cover water sources or change water at least twice per week.
Use insect repellents approved for the species.”
No human cases have been reported so far this season, but officials emphasize ongoing monitoring as infected mosquitoes have been detected in multiple regions.
