West Nile Virus (WNV) in Animals 

Dogs and Cats

A relatively small number of WNV infected dogs and WNV infected cats have been reported to CDC.

There is no specific treatment for WNV infection in dogs and cats. Full recovery from the infection is likely. Treatment would be supportive (managing symptoms, if present) and consistent with standard veterinary practices for animals infected with a viral agent.  There is no documented evidence of dog or cat-to-person transmission of West Nile virus.

If your animal becomes infected with WNV, this suggests that there are infected mosquitoes in your area. You should take measures to prevent mosquitoes from biting you (use repellent and wear protective clothing).  DEET-based repellents, which are recommended for humans, are not approved for veterinary use (largely because animals tend to ingest them by licking.) Talk with your veterinarian for advice about the appropriate product for use on your pet.


Horses, like humans and other companion animals, are infected with WNV thru the bite of an infected mosquito.  While there have been cases of WNV in horses in Arkansas, most horses infected with WNV recover fully from the infection.  There is no documented evidence of horse-to-person transmission of West Nile virus. 

West Nile virus vaccines for horses are available through veterinarians. Horse owners should strongly consider vaccinating their equines. Consult your veterinarian for more details on timing of vaccination.  For more information on WNV and horses, please visit the USDA website Animal and Plant Health Inspection Service (APHIS).