West Nile virus causes infection and inflammation of the central nervous system. It is transmitted by mosquitoes, which feed on infected birds or other animals and can infect horses, humans and other mammals.

In 2012 through mid-December, 42 states reported 654 cases of West Nile in horses, with Louisiana and Texas having the most confirmed veterinary cases — 62 and 117, respectively.1 Only eight states reported no veterinary cases of West Nile in 2012.

Vaccination remains the most effective way to help protect horses against this mosquito-borne disease. Without vaccination, the risk of West Nile infection can be 50 times higher than if you vaccinate your horse annually with WEST NILE-INNOVATOR®.2 This trusted vaccine can help offer demonstrated protection against West Nile virus. According to the American Association of Equine Practitioners guidelines, West Nile virus is considered a core vaccination requirement, along with vaccinations for Eastern equine encephalomyelitis, Western equine encephalomyelitis, tetanus and rabies.3 All horses should receive a West Nile virus vaccine annually.

To remind horse owners of the importance of vaccination against West Nile virus, Pfizer Animal Health is launching new advertisements and a commercial for WEST NILE-INNOVATOR. The new campaign features horses on a hot walker at night surrounded by glowing bug zappers. This imagery shows that there is an easier way to help protect your horse against West Nile virus, by using WEST NILE-INNOVATOR. Watch the commercial at http://www.youtube.com/watch?v=SrF-wkAErtk.

West Nile does not always lead to clinical signs of illness. For horses that show clinical illness, the virus can cause loss of appetite and depression. Other clinical signs may include fever, weakness or paralysis of hind limbs, impaired vision, ataxia, aimless wandering, walking in circles, hyperexcitability or coma.4 Horse owners should contact their veterinarian immediately if they notice any of these behaviors. The case fatality rate for horses exhibiting clinical signs of West Nile virus infection is approximately 33%.1

Preventive measures can help avoid West Nile infections of your horses. These measures should include destroying any mosquito breeding habitats by removing all potential sources of stagnant water, cleaning and emptying any water-holding containers and vaccination.

No matter the location, horses are at risk for West Nile virus. By eliminating mosquito breeding habitats and providing proper vaccination, horse owners can do their part to help prevent West Nile virus infections.

For more information on the WEST NILE-INNOVATOR line of vaccines, contact your Pfizer Animal Health representative, visit www.westnileinnovator.com/protect or call 855-4AH-PFIZER (855-424-7349).

About Pfizer Animal Health

Pfizer Animal Health, a business unit of Pfizer Inc., is a global leader in the discovery, development, manufacture and commercialization of animal health medicines, diagnostics, genetic tests and vaccines, with a focus on both livestock and companion animals. For more than 60 years, we have been committed to enhancing the health of animals and bringing solutions to our customers who raise and care for them. To learn more, visit www.pfizeranimalhealth.com.


1 U.S. Department of Interior. U.S. Geological Survey. Disease Maps 2012. Updated October 30, 2012. Available at:

http://diseasemaps.usgs.gov/wnv_us_veterinary.html. Accessed December 18, 2012.

2 Epp T, Waldner C, Townsend HG. A case-control study of factors associated with development of clinical disease due to West Nile virus, Saskatchewan 2003. Equine Vet J 2007; 39(6):498–503.

3 American Association of Equine Practitioners. Core Vaccination Guidelines. 2008. Available at: http://www.aaep.org/core_vaccinations.htm. Accessed August 3, 2012.

4 The Florida Department of Agriculture and Consumer Services: The Division of Animal Industry. West Nile Virus. Updated March 11, 2011. Available at: http://www.freshfromflorida.com/ai/main/wnv_main.shtml. Accessed August 3, 2012.


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