Nearly one year ago, Arizona experienced its first West Nile Virus case in a horse for the 2005 season. It never need happen again, as a vaccine is available to protect horses.
However, the vaccine must be given before the animal is infected and that is why horse owners need to contact their veterinarians to schedule vaccinations as soon as possible. Unlike humans, horses are protected from the disease through a simple vaccination.
Horses become infected with West Nile virus the same way humans become infected -- by the bite of infectious mosquitoes. The mosquitoes become infected after feeding on an infected bird.
The vast majority of horses that are bitten by infected mosquitoes do not become ill, but those that develop severe encephalitis often die. Recovered horses often suffer from residual damage to their nervous system.
Horses that are infected with West Nile Virus are not contagious to humans or to other horses. Normal infection control precautions should be followed when caring for a sick horse.