A 4-year-old unvaccinated Quarter Horse gelding from St. Croix County is the first reported Wisconsin horse to have become infected and die from West Nile Virus (WNV) this year.  Horse owners are urged to get horses vaccinated to prevent further spread of WNV and another mosquito-borne disease, Eastern equine encephalitis (EEE). Neither of the viruses is contagious between horses, but can be carried by mosquitos from an avian, or bird, host to horses and humans. While humans may also be infected by both WNV and EEE, the viruses do not pass directly between people and horses.  Mosquitoes biting warm-blooded animals is the only route of transmission. Besides vaccination, steps should be taken to limit horses’ exposure to mosquitoes during warm weather.