Horse owners in Washington should take advantage of the vaccines available to prevent West Nile virus, particularly as the state led the nation last year in the number of horses testing positive for the disease.

West Nile virus (WNV) is spread by mosquitoes that have fed on an infected bird. It is not spread from horses to other animals.

A total of 41 Washington horses were confirmed positive for WNV last year. These included 26 horses in Yakima County; 10 horses in Grant County; four horses in Benton County; and one horse in Kittitas County. In previous years, WNV horse cases have been detected in Western Washington as well.

Although the first confirmed case of WNV in a horse last year wasn’t reported until Aug. 1, State Veterinarian Leonard Eldridge, DVM, said there’s no guarantee that pattern will hold true this year