New Jersey Department of Agriculture, Division of Animal Health

Memo

To: Veterinarians

From: Nancy E. Halpern, D.V.M., State Veterinarian

Date: July 13, 2006

Re: Equine Viral Arteritis Outbreak in New Mexico

     On June 26, 2006, the Office International des Epizooties (O.I.E.) Reference Laboratory for Equine Viral Arteritis (EVA) at the University of Kentucky College of Agriculture's Maxwell H. Gluck Equine Research Center confirmed an outbreak of equine viral arteritis infection involving fetal losses among mares on a Quarter Horse breeding farm in New Mexico. This finding was based on the widespread prevalence of high antibody levels to the virus in both mares and stallions, plus virus isolation from the semen of 2 stallions. On the same day, the outbreak was reported to the New Mexico Livestock Board in Albuquerque, N.M., which is now investigating the potential for spread of the infection to other premises.

     EVA was first recognized in the United States in an outbreak in Kentucky in 1984. Equine viral arteritis is characterized by fever, depression, edema, conjunctivitis, nasal discharge, and abortions. Mortality is rare but economic losses can be significant. The economic impact includes decreased demand for carrier stallions as breeders, deaths in young foals, and abortions in 10-50 percent of susceptible mares.

     Equine viral arteritis is caused by an RNA virus in the genus Arterivirus (family Arteriviridae). Equine arteritis virus is restricted to the Equidae. The prevalence of the virus can vary significantly among horse breeds; a high rate of infection is reported in standardbreds.

     For more information about this outbreak or about EVA, the following resources are available:

• The New Mexico Livestock Board has information regarding this outbreak on its website, which can be accessed at http://www.newmexicolivestockboard.com under "critical events."
• Detailed information about EVA from the USDA, including history, transmission, symptoms, clinical signs, treatment, prevention and control is available at http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahequineva.html.

     Veterinarians interested in submitting samples to the NJDA Animal Health Diagnostic Laboratory should send serum to the laboratory. The cost of the test is $ 15.00.