It primarily circulates between wild birds and mosquitoes ( Culex tarsalis being a major vector). Horses and humans act as "dead-end" hosts, meaning they can contract the disease but typically do not develop high enough viral levels to pass it back to mosquitoes.
The disease is caused by the Western Equine Encephalomyelitis Virus (WEEV) , a member of the Alphavirus genus in the Togaviridae family. mal oeste
Hypersensitivity to sound/touch, wandering, and ataxia (lack of muscle coordination). It primarily circulates between wild birds and mosquitoes