Let’s face it–we were getting comfortable, perhaps complacent, in our twice-a-year visits from our horse’s veterinarians for inoculations against the old, familiar diseases…Eastern and Western equine encephalitis, influenza, rabies, rhino, strangles, and maybe even botulism in some areas of the United States. Then in late summer of 1999, a new virus showed up that was about as welcome as a nasty hoof abscess the day before the championship. It was a disease with a life cycle that included mosquitoes and birds–creatures that are ever-present on our farms.

The talk in barn aisles across America turned to this next big disease–West Nile virus (WNV). The descriptions of the neurologic signs that unfortunate victims displayed were terrifying horse owners up and down the East Coast, if not across the entire United States. How susceptible is my horse? What can be done to prevent him from contracting it? If he gets sick, can my veterinarian save him?

In the early days of the emergence of WNV in the United States, there weren’t many answers. While the virus had been encountered in Africa (as its name suggests), Europe, and the Middle East, it hadn’t been seen in the Western Hemisphere, and it was unclear how it would behave in the unique ecology of North America. Researchers, veterinarians, and public health officials teamed up to organize WNV surveillance and begin studying the disease, while giving horse owners the best advice they could.

Progress was made–more than 300 scientific papers have been published on WNV since 1999. Six years later, we understand the disease better, we have more ways to reduce the mosquito populations on our farms, and there are two reliable vaccines on the market to protect our horses (and a new vaccine will be hitting the market soon). Many clinicians feel confident in the WNV treatment methods they’ve adopted