The West Nile Virus is a contagious (although only through mosquitoes) and sometimes fatal form of encephalitis (inflamation of the brain) that is incubated
in birds and transmitted by mosquitoes. It first appeared in the United States in 1999 and it is spreading.
This disease can be contracted by almost any animal, but birds, horses, and humans seem to be at most risk. However, while some cases are fatal, many animal and most people recover from the virus.
Signs of West Nile Virus in horses can include ataxia, difficulty walking, knuckling over, head tilt, muscle tremors, and the inability to rise.
There is an effective equine vaccine available that should become a regular part of the horse owners health managment program. The vaccine for Venzuelan,
Eastern and Western Equine Encephalitis does NOT protect an animal against the West Nile Virus.