MEMORANDUM

TO: AHC Members
    Interested Parties

FROM: American Horse Council

DATE: 10-30-97

RE: Report of the Working Group on EVA

In June of 1996, the American Horse Council (AHC) was asked to address the issue of Equine Viral Arteritis (EVA) because of its continuing economic impact on U. S. horse owners. The AHC established a working group to develop an industry-driven control program for EVA that would include a protocol for identifying and managing sources of equine arteritis virus (EAV) infection by way of carrier stallions or virus infective semen.

Representatives of the following breed organizations were appointed to the AHC working Group on EVA: the American Quarter Horse Association; the U. S. Trotting Association; the Tennessee Walking Horse Breeders & Exhibitors Association; the International Arabian Horse Association; the Appaloosa Horse Club; the Federation of North American Sport Horse Registries; and the Jockey Club.

In addition, the group included Dr. Ralph Knowles from the Maryland Department of Agriculture, chairman of the U.S. Animal Health Association's Committee on Infectious Diseases of Horses; Dr. Don Lein, Director of the Veterinary Diagnostic Laboratory at Cornell University, and Dr. Don L. Notter, Kentucky State Veterinarian.

The goal of the working group has been to develop a voluntary, industry-driven protocol that will assist the stallion owners in preventing establishment of the carrier state in stallions and minimize the risk of EVA-related abortion in mares and which will also serve to limit the liability associated with the use of stallions which shed equine arteritis virus or infective semen. The protocol will also serve as a basis for establishing controls over the importation of EAV carrier stallions and infective semen.

EVA is a contagious viral disease of members of the horse family that is primarily spread by direct contact with horses acutely infected with equine arteritis virus. While it is considered a respiratory infection of the horse, the disease can also be spread through breeding a carrier stallion to a susceptible mare.

The relative increase in the number of confirmed outbreaks of EVA in horses in the U.S. in recent years has begun to concern horse owners, notwithstanding the fact that from the medical perspective, EVA is not regarded as a disease of major significance. Horse owners need to be provided with a protocol that will help to ensure protection of their horses from EVA and prevent problems that could result from the use of carrier stallions or infective semen. Other matters that need to be addressed include the liability of owners whose stallions shed EAV and the problems associated with the movement of carrier stallions or virus positive semen at the national and international level.

Attached is a copy of a protocol developed by the working group to help horse owners identify carrier stallions and EAV infective semen so that either the former or the latter may be used without attendant risk of the occurrence of EVA. Adoption of the protocol would greatly lessen the likelihood that the disease would be driven underground; which, were it to occur, would greatly hinder horse owners being able to protect their horses effectively against this disease.

Because of the potential economic threat posed by EVA, it is highly advisable that breed registries recommend that the attached protocol be adopted by breeders as part of good breeding practice. The protocol provides a practical, realistic and unified approach that permits the continued use of carrier stallions or infective semen.

Some breed registries have already taken such an initiative. The North American Department of the Warmblood Studbook of the Netherlands instituted a requirement last year that in order for foals to be eligible for registration each stallion must be tested for EVA and the results published in the annual directory. Owners are provided with a protocol that allows for the continued use of carrier stallions and effectively protects mares against the disease. Although the protocol was initially implemented on a voluntary basis, membership response for the initiative was so favorable that it is now a mandatory program. As an additional protection, the Registry requires that frozen semen imported into the U.S. for resale in this country be tested for EAV at the Gluck Equine Research Center, University of Kentucky.

Questions regarding the protocol should be directed to Amy W. Mann at the AHC offices, 202-296-4031.