West Nile Virus and Eastern Equine Encephalitis at Record Levels in 2012

FOR IMMEDIATE RELEASE — MAR. 21, 2013 — With more than 600 cases of equine West Nile virus (WNV)1 and more than 200 cases of Eastern Equine Encephalitis (EEE)2 reported in 2012, it was one of the worst years on record for mosquito-borne diseases.3 Besides the alarming number of equine cases, more than 5,000 cases of WNV were reported in humans, resulting in 243 deaths.3 According to the Centers for Disease Control and Prevention, this was the highest on record since 2003.3

“Horse owners can become complacent when it comes to diseases like West Nile virus because if they haven’t seen it in their area recently, they simply don’t think it will happen to their horses,” says Hoyt Cheramie, Manager, Merial’s Large Animal Veterinary Services. “But what we saw in 2012 is that although the number of cases had declined during the past several years, it only takes one heavy mosquito season for the numbers to jump back up to record levels.”

The best way to help protect horses from mosquito-borne diseases is to vaccinate, adds Dr. Cheramie. “It simply isn’t worth taking a chance when it comes to diseases like West Nile virus and Eastern Equine Encephalitis,” he says. “Both of these very preventable diseases have effects that are devastating, for the horse and the horse owner.”

As the spring vaccination season approaches, horse owners should be sure to include WNV and EEE vaccinations on their schedules. Even if a horse owner has allowed a lapse in the horse’s vaccination schedule, it isn’t too late, but it does become more important which product they choose. Merial’s RECOMBITEK® rWNV-EWT showed onset of immunity to West Nile virus in naïve horses just 26 days after the initial dose in a two-dose series.4

While vaccination is the best way to help protect horses from diseases such as WNV and EEE, staying informed about the threat of equine diseases can also be helpful. Merial’s Outbreak Alert program, launched in June 2011, is a tool horse owners can use to evaluate risk, especially when traveling.

The program features a website with maps indicating the presence of confirmed cases in all species, including the carriers of WNV, EEE, Western equine encephalitis, influenza, Potomac Horse fever, Equine herpesvirus and rabies. Free, printable information about each of the diseases, their clinical signs and treatments, is also available on the site.

Besides the mapping and educational tools, the Outbreak Alert program offers a free alert system for horse owners and veterinarians who sign up through the site. Those who are signed up for the service receive a free text or e-mail alert when a disease has been confirmed in their geographic area. Horse owners traveling with their horses can enter multiple ZIP codes to stay informed while on the road.

Since its inception, thousands of Outbreak Alert subscribers have received messages, making them aware of the threats surrounding them. These alerts may be for equine cases, but also may include insects or other species – including humans – as they are important indicators of the presence of these diseases.

“A horse can be just one mosquito bite away from becoming infected with the West Nile or Eastern Equine Encephalitis virus,” says Dr. Cheramie. “Likewise, a horse can be just one raccoon or skunk bite away from becoming infected with rabies. When horse owners recognize these diseases may exist right in their own backyards, it helps them realize the cost of vaccinating is a small price to pay for the health of their horses and peace of mind.”

An additional benefit to horse owners is the “Exclusive Offers” section of the Outbreak Alert website which features special savings for members. “We know that in these tough economic times, it can be tempting to skip a scheduled vaccination,” says Dr. Cheramie. “We’re trying to do our part to help horse owners protect the health of their horses.”

Veterinarians can use Outbreak Alert as a tool to help educate their clients about the threat of disease. “Too often, horse owners think because they haven’t heard about a disease in their area that it doesn’t exist,” says Dr. Cheramie. “Through Outbreak Alert, veterinarians around the country have been able to show their clients the proximity of equine diseases and stress the importance of vaccinating.”

As always, horse owners should work in conjunction with their veterinarians when determining a vaccination schedule. According to the American Association of Equine Practitioner (AAEP) guidelines, horses should receive at least five core vaccinations, which include protection against tetanus, EEE/WEE, WNV and rabies.5 Other vaccinations are given based upon risk, which should be determined in conjunction with a veterinarian and may include vaccinations for diseases such as Potomac Horse fever, strangles, rhino and equine influenza.6

“Horse owners have made significant investments in their horses, financially and emotionally,” says Dr. Cheramie. “Helping protect their health and well-being with an appropriate vaccination schedule is the best decision when the alternative is to cope with losing a horse or treating a horse for a preventable disease.”

For more information about Merial’s vaccines, visit equinewnv.com.

For more information or to sign up for Outbreak Alert, visit outbreak-alert.com.


Recombitek rWNV-EWT vaccine is a combination vaccine labeled to aid in the prevention of disease and viremia due to West Nile virus and encephalitis caused by Eastern Equine Encephalomyelitis Virus (EEE) and Western Equine Encephalomyelitis virus (WEE) and tetanus caused by the Clostridium tetani toxin.7

®RECOMBITEK is a registered trademark of Merial Limited. ©2013 Merial Limited, Duluth, GA. All rights reserved. EQUIBGN1303 (02/13)

1 Animal and Plant Health Inspection Service. Animal Health Monitoring & Surveillance Web site. Available at: http://www.aphis.usda.gov/vs/nahss/equine/wnv/wnv_distribution_maps.htm. Accessed February 6, 2013.

2 Animal and Plant Health Inspection Service. Animal Health Monitoring & Surveillance Web site. Available at: http://www.aphis.usda.gov/vs/nahss/equine/ee/eee_distribution_maps_htm. Accessed February 6, 2013.

3 Centers for Disease Control and Prevention website. Division of Vector-Borne Diseases. 2012 West Nile virus update: December 11. Available at: http://www.cdc.gov/ncidod/dvbid/westnile/index.htm. Accessed February 6, 2012.

4 Siger L, et al. Assessment of the efficacy of a single dose of a recombinant vaccine against West Nile virus in a response to natural challenge with West Nile virus-infected mosquitoes in horses. Am J Vet Res. 2004;65(11):1459-1462.

5 American Association of Equine Practitioners. Core Vaccination Guidelines. Available at: http://www.aaep.org/vaccination_guidelines.htm. Accessed October 30, 2012.

6 American Association of Equine Practitioners. Risk-Based Vaccination Guidelines. Available at: http://www.aaep.org/risk_based.htm. Accessed October 30, 2012.

7 RECOMBITEK rWNV-EWT product label.



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