Duluth, Ga. — Merial, a world-leading animal health company, announced today the release of a new equine vaccine - RECOMBITEK® Equine West Nile Virus (WNV) vaccine. The recent USDA approval of RECOMBITEK Equine West Nile Virus vaccine offers veterinarians a first-of-its-kind product backed by cutting edge science to offer fast-acting and long-lasting protection from the often deadly West Nile Virus.

"The RECOMBITEK West Nile Virus vaccine uses recombinant DNA technology to stimulate a fast, multifaceted and long-lasting immune response proven by natural mosquito challenge of West Nile Virus," says Dr. Mike Murray, Merial Equine Technical Director for Strategic Development. "The fast acting immune response was demonstrated in a controlled trial that showed horses were protected from viremia caused by West Nile Virus infection when challenged as early as two weeks after completion of the two-vaccination series."

The benefits of recombinant vaccine technology include a fast, multifaceted (humoral and cell-mediated) immune response, targeted antigen presentation, and a level of safety inherent to this technology due to the fact that there is no possibility of live virus replication.

As a leader in recombinant DNA technology, Merial manufactures and markets 11 of the 12 companion animal and equine vaccines that use recombinant DNA technology, including RECOMBITEK vaccines for dogs, PUREVAX® for cats, and in Europe, PROTEQFL™, which induces rapid and long-lasting immunity to equine influenza.

"Recombinant technology vaccines have an intrinsic safety factor because animals receiving the recombinant vaccine are never exposed to the disease-producing organism," Murray says.

In 2002, West Nile Virus exploded throughout the U.S. equine population, resulting in 15,257 documented cases. The USDA estimates a mortality rate of approximately one third* of horses showing clinical signs of WNV disease. Although the total number of cases in the United States declined in 2003, WNV presented itself in various geographic regions, including a five-fold increase in clinical cases reported in the Mid-Atlantic States, demonstrating that this disease remains dangerous and unpredictable.

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*aphis.usda.gov Website, "Questions & Answers About West Nile Virus" (March 2003), Accessed December 16, 2003, at: http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/faq_ahwnv.html.

®RECOMBITEK and PUREVAX are registered trademarks and ™PROTEQFLU is a trademark of Merial.
©2004 Merial Limited Duluth, GA. All rights reserved.

Merial is a world leading innovation-driven animal health company, providing a comprehensive range of products to enhance the health, well-being and performance of a wide range of animal species. Merial operates in more than 150 countries worldwide. Its 2002 sales were in excess of $1.7 billion. Merial Limited is a joint venture between Merck & Co., Inc., and Aventis, S.A. For more information, please see www.merial.com.