Rabid animals were reported from every state except Hawaii in 1997, according to the Centers for Disease Control and Prevention (CDC), Atlanta, GA. Rabies was confirmed in 47 horses, donkeys and mules in 21 states and Puerto Rico (Figure 2) in comparison to 46 equid cases in 1996. These figures represent only laboratory-confirmed cases since not every neurological horse which dies is submitted for necropsy and rabies testing.

Equine rabies is a sporadic, but highly fatal, zoonotic disease caused by a Lyssavirus. Rabies affects both animals and humans. All warm-blooded animals can be infected with rabies but it is most often transmitted in Canada by foxes, raccoons, skunks and bats.