West Nile Virus in Dogs & Cats

Trisha Consunji: 916-649-0599 (California Veterinary Medical Association)



Take Precautions Against Mosquito-Borne Disease

Sacramento – Can Fido or Kitty get West Nile virus? Yes, but it is extremely rare and very unlikely your pet will get it. According to the California Veterinary Medical Association (CVMA) and research posted by the Centers for Disease Control and Prevention, dogs and cats exposed to West Nile virus (WNV) will often test positive for exposure to the disease but most will not display any clinical symptoms or behavioral changes.

Cats are more likely than dogs to show minor signs of infection, especially mildly elevated temperatures and lethargy, but neither animal has been shown to exhibit neurological problems. Both dogs and cats developed titers of WNV when bitten by infected mosquitoes or fed infected birds or mice; however, they are not considered to be natural hosts for further spreading the disease. Dogs especially are unlikely to serve as amplifying hosts since the virus level appears to be low in infected dogs. Cats, although not as effective as birds to serve as hosts for WNV, appear to be capable of infecting mosquitoes, although it is unclear whether the virus levels in their bloodstream are at a high enough level to do so.

There is no vaccine or specific treatment for dogs or cats infected with WNV. Pet owners who are concerned about their pets displaying symptoms consistent with WNV should consult their veterinarians. Worried pet owners should know there is no documented evidence of dogs or cats transmitting WNV to a person. Preliminary studies have not been able to detect WNV in the saliva of infected dogs, so there does not appear to be a risk of humans becoming infected through a dog or cat bite.

To prevent WNV and other mosquito-transmitted diseases like heartworms, pet owners should take precautions for their pets and keep them indoors during the peak mosquito-feeding hours of early in the day, at dusk, and at night. Do not apply DEET-based mosquito repellent on pets since it is a toxic substance and can be ingested by licking. WNV vaccines formulated for large animals, such as horses, should not be given to small animals like dogs and cats. Pet owners should consult their veterinarians for appropriate products for their pets.

Pet birds are especially attractive to preying mosquitoes and should be kept indoors. Pet birds like parrots, cockatiels, and canaries are susceptible to WNV, though the risk is low. Bird owners should take extra precautions to ensure their window screens are in good repair before leaving windows open and remove any standing water, excellent for breeding mosquitoes, lying around the home.

For more information about West Nile virus in domestic pets and horses, contact your local veterinarian or the California Veterinary Medical Association at 916-649-0599. To access past CVMA press releases, visit the CVMA Media Center in the News Room at


The California Veterinary Medical Association is the largest state veterinary medical association in the United States, with more than 7,000 members. Founded in 1888, its mission is to serve its membership and community through innovative leadership and to improve animal and human health in an ethically and socially responsible manner.

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