Equine owners, associations and other interested persons have until November 20 to provide input on the U.S. Department of Agriculture's proposed programs for Equine Viral Arteritis (EVA), a highly contagious, but not widespread, respiratory disease of equine in the U.S.

"We want the equine community to comment on the options offered at the federal level, as it will undoubtedly affect us locally, said Dr. Terry Conger, veterinarian and state epidemiologist for the Texas Animal Health Commission (TAHC), the state's livestock health regulatory agency. [EVA should not be confused with the incurable virus Equine Infectious Anemia (EIA), for which Texas has an active control and regulatory program. The TAHC has no regulations for EVA.]

"Currently, there is no federal program to control EVA, which, after an incubation period of about a week, can cause infected equine to run fever, lose their appetite, and develop nasal discharge and conjunctivitis (red, swollen eyes). While in many instances, there are no signs of illness, a high percentage of infected pregnant mares will abort or deliver foals that do not survive," said Dr. Conger.

"Affected mares, geldings or sexually immature stallions will usually eliminate the virus and develop a strong immunity against the disease," he said. "Stallions, on the other hand, can harbor the disease in their reproductive system as long as 15 years and shed the virus continuously or only periodically. When stallions are 'shedders,' they can infected mares during breeding. Infected mares can also infect their foals in utero, or prior to delivery."

"A very effective vaccine is available," said Dr. Conger. "Foals are vaccinated between the ages of six and 12 months, while blood-test negative breeding stallions can be inoculated yearly. Mares that will be bred to infected stallions should be vaccinated at least three months prior to breeding, with a booster administered three or four months after the initial vaccination. Unfortunately, these vaccinated animals can test positive on EVA blood tests, which causes problems if the equine is to be exported." "In addition to health implications, EVA also has economic repercussions," said Dr. Conger. "Abortions, foal deaths and lost breeding seasons resulting from this disease can substantially impact the equine industry. Most worrisome is the challenge to guard against the spread of disease by infected stallions. Many countries also bar the importation of affected equine and/or their semen."

A full text of the proposed programs may be found on the internet at http://www.aphis.usda.gov/ppd/rad/webrepor.html or obtained from the TAHC by calling 1-800-550-8242, ext. 710. Dr. Conger has summarized the USDA's five possible programs, all of which include disease education and range from voluntary to highly restrictive:

• no USDA regulatory involvement
• focus on disease education
• equine industry to determine method to identify infected stallions (and semen).

Voluntary control program:

• Equine industry to manage and monitor program, with assistance of USDA's Animal and Plant Health Inspection Service (APHIS) and individual states
• USDA-APHIS would quarantine and test internationally imported stallions and/or semen; record results on the import permit and notify animal health regulatory officials in the state of destination.
• States urged to consider testing positive imports to attempt virus isolation.
• Under this program, states are urged to develop testing program for domestic stallions and semen, control in-state movement of affected equine, and make test records public record.

Voluntary and Uniform Control Program:

• Equine industry, USDA and states to develop national standards, called uniform methods and rules (UMR), encompassing EVA disease control, detection, and movement requirements for stallions that are "shedders" of the virus.
• USDA-APHIS would quarantine and test internationally imported stallions and/or semen; record results on the import permit and recommend the state of destination hold the positive stallions for virus isolation tests.
• States urged to test domestic stallions and semen; require tests for interstate movement, and conduct virus isolation (confirmation) tests on all blood-test positive stallions. Test records would be public record.

Certification Program

• USDA-APHIS would release internationally imported blood-test positive stallions and/or semen only to states participating in certification program.
• Known infected domestic stallions and/or semen also could move only to certified states.
• Certified states would run virus isolation (confirmation) tests on every blood-test positive stallion entering the state, and test and record results on all incoming domestic equine semen.
• Certified states would also regulate the in-state movement of infected semen and stallions.

Eradication Program

• Equine industry, USDA and states to develop national standards, called uniform methods and rules (UMR), encompassing EVA disease control, detection, movement requirements and prevention.
• USDA-APHIS to quarantine and test imported stallions and/or semen; move positives to APHIS-approved site for virus isolation (confirmation) testing. Results to be recorded on import permit accompanying animal or semen.
• USDA-APHIS would require domestic stallions and semen to be tested for EVA prior to interstate movement, with results recorded on the certificate of veterinary inspection.
• Movement permits required for interstate movement of infected semen or stallions shedding the EVA virus. USDA- APHIS recommends semen from these affected stallions undergo a virus isolation test prior to the first breeding in the new state.
• USDA-APHIS to initiate an EVA-vaccination program for domestic mares.

To provide input on these proposed EVA programs, send three copies of comments to:

Docket #99-074-1
Regulatory Analysis and Development
PPD, APHIS Suite 3C0-3
4700 River Road, Unit 118
Riverdale, Maryland 20737-1238,