WNV Information for Veterinarians and Horse Owners

West Nile Virus (WNV) affects horses much more often than any other domestic animal. Although most horses do not exhibit any signs of clinical illness, the health impact can be severe in those that do. In the U.S. prior to the 2004 California outbreak, of those horses that developed clinical illness, approximately 30% died or had to be euthanized and another 17% suffered from long–term related debilitation. Vaccines are available to help protect horses from West Nile virus.