West Nile Killing More Horses in California

West Nile virus is killing California horses at higher rates than in other states.

Forty-two percent of the 349 California horses infected so far this year have either died or have been euthanized, the state Department of Food and Agriculture reported. Nationwide, the death rate for West Nile-infected horses is about 30%, according to the Centers for Disease Control and Prevention.

In Riverside County, 21 of 38 West Nile-infected horses, or 55%, died or were put down. The county is second in the state behind Stanislaus County, which has had the highest number of equine cases.