Intervet Inc., a global leader in animal-vaccine research and development, announces the availability of PreveNile, the first one-dose West Nile virus (WNV) vaccine available for primary immunization of horses. "PreveNile offers the most advanced WNV technology available for horses," says Craig Barnett, D.V.M., Intervet Senior Equine Technical Services Specialist. "PreveNile is the first and only one-dose USDA-approved equine WNV vaccine, and it offers the most comprehensive label claim of all WNV products. This means superior - and convenient - long-lasting protection for your horse."
Advanced Science, Powerful Protection
In research studies conducted by Maureen Long, D.V.M., Dipl. ACVIM, assistant professor of large animal veterinary medicine at the University of Florida, PreveNile demonstrated protection against clinical signs observed in horses naturally infected with WNV.
"PreveNile is proven to significantly reduce clinical signs of WNV in horses vaccinated with a single dose as compared to unvaccinated horses," says Long. "Vaccination resulted in 100 percent survivorship, as well as a significant reduction in clinical signs of WNV disease. In addition, the vaccine was shown to provide a full 12 months of protection against WNV disease in unvaccinated yearlings … again, that's with just a single-dose."
"This type of protection is particularly important for previously unvaccinated horses, providing added assurance in the face of an outbreak," Long adds.
"This is the same technology being tested for the first-ever human WNV vaccine," says Marv Jahde, Intervet's Marketing Manager, Equine Products. "The ChimeriVax technology combines two similar mosquito-born viruses (yellow fever and WNV) into one, creating a chimera vaccine."
The yellow fever human vaccine is a safe, highly effective, well-tolerated vaccine that has been utilized for more than 60 years in more than 400 million people.
The chimera vaccine technology is more convenient because it stimulates immunity without requiring a "booster" dose. In addition, only a single dose of PreveNile is required for horses previously vaccinated with other WNV vaccines.
"One-dose administration translates into greater convenience and less cost for the horse owner and less stress on the horse," says Barnett. "In addition, the vaccine is proven safe. In field safety trials, 99.9 percent of vaccinated horses did not experience any adverse reactions, including injection-site reactions."
Use in Pregnant Mares and Foals
PreveNile is safe for use in foals 4 months of age or older.
In PreveNile field trials, 302 pregnant mares were vaccinated, including 17 mares in the first trimester of gestation, 11 mares in the second trimester of gestation and 274 mares in the third trimester of gestation. No post-vaccinal adverse events were observed in any of the mares. Studies to evaluate safety in these mares through foaling are ongoing.
PreveNile may be used safely in foals, beginning at age 4 months, as well as horses previously vaccinated with another WNV vaccine. Vaccination consists of a single, 1-mL dose administered intramuscularly. Revaccinate annually with a single dose. Speak with your veterinarian about including PreveNile in your horse's vaccination program.
Do We Need Another WNV Vaccine?
"WNV never can be eradicated," says Long. "The virus continues to pose a significant threat to both humans and horses."
Long, considered one of the leading equine immunologists, says vaccine technologies continue to improve and evolve.
There is no cure for WNV. According to the U.S. Department of Agriculture's Animal and Plant Health Inspection Service, more than 30 percent of the 23,750 cases of WNV diagnosed in horses since 1999 have resulted in death. A sound vaccination program along with good environmental management practices, such as the elimination of standing water and use of mosquito repellent, provide the best means for controlling spread of the virus.
"PreveNile represents the next generation of equine WNV vaccine technologies, which provide long duration of immunity and more efficacious protection with a single dose," says Long.
For more information about PreveNile and the full line of Intervet equine products, contact your veterinarian or Intervet Customer Service at 1-800-441-8272 or visit www.prevenile.com.