One equine case of West Nile virus (WNV) in Florida had been confirmed by serological testing as of May 1, according to Leroy Coffman, DVM, Florida’s state veterinarian and director of the Division of Animal Industry. This was the first reported equine case of WNV in the state this year, and possibly the first in the United States this year.

The WNV case was confirmed in an unvaccinated 10-month-old Quarter Horse in Levy County. The horse first started showing clinical signs on March 27 and died a few days later.

West Nile virus is spread by the bite of an infected mosquito, with birds, horses, and humans being the most affected species. The fatality rate in horses is around 30-40%; the human mortality rate is 10-15%.

The first equine cases of WNV appeared in the United States in 1999. Since then, the disease has spread rapidly across the country and is now considered endemic. In years past, the National Veterinary Services Laboratory in Ames, Iowa, was the only laboratory that confirmed WNV test results. Now, many laboratories are performing diagnostic tests