EVA Outbreak in New Mexico

There has been an outbreak of Equine Viral Arteritis (EVA) at MJ Farms in Veguita, New Mexico, resulting in an estimated loss of 40% of on-farm pregnancies, as well as infection of stallions. EVA is primarily a respiratory disease, but has serious reproductive implications, as it can cause abortion in mares, and remain in the stallion's reproductive tract, being shed into semen at the time of ejaculation. This infected semen, if then introduced into non-protected mares, is likely to result in infection of that mare, with the potential for transmission to other horses, and the possibility of an abortion storm such as MJ Farms has experienced. As this is a virus, it cannot be controlled by the use of antibiotics, nor will it be destroyed by freezing. Consequently infected semen will remain infectious even if shipped cooled or frozen. The best form of control is preventative in the form of vaccination of susceptible animals. It should be noted that while the vaccine Arvac (Fort Dodge) is available in the USA, it may not be available in all countries, and indeed there may be local restrictions as to the use of such a vaccination. EVA in the animal may be asymptomatic, causing more problems as it may not be recognized that there is an active infectious state until serious repercussions such as abortion or pregnancy failures become apparent. As it is primarily a respiratory disease, it can be spread by aerosol transmission rather than sexually, presenting further complications as asymptomatic but infectious animals may be present at shows and other equine gatherings unbeknownst to other attendees - or even the owners themselves.

Don't Panic!!

It is important to emphasize that EVA is not a disease to be panicked about, but rather a disease to be managed - something achieved easily with the appropriate vaccinations. It is not a new disease and appears to have been around for possibly over 100 years, although it was not specifically identified until more recently in the 1950's. Dr. Peter Timoney of the Gluck Center in Lexington KY, USA is a world-renowned expert on EVA (the virus itself incidentally is known as "equine arteritis virus" or EAV, while the disease is "equine viral arteritis" or EVA), and has prepared a comprehensive article on the disease entitled Equine Viral Arteritis: Is the Disease a Cause for Industry Concern? (available in Adobe .pdf format at that link - but note that at 12 Meg it is a large file). It is certainly an article that is food for thought!