Equine herpes myeloencephalopathy (EHM) is a very serious disease which is often fatal. Fortunately, there are excellent resources available to become informed of the details of the virus and the most effective ways to prevent its spread:
1. Keep track of recent outbreaks of infectious disease: www.equinediseasecc.org/outbreaks.aspx
2. For a brief summary of information, this brochure will tell you what you need to know about the neurologic form, EHM:https://www.aphis.usda.gov/vs/nahss/equine/ehv/equine_herpesvirus_brochure_2009.pdf
3. A very thorough description of EHM through University of California Davis:
http://www.vetmed.ucdavis.edu/ceh/local_resources/pdfs/currenthealth_whitepaperEHM.pdf
Some Points to Consider On Vaccination & EHM:
1. There is currently no vaccine available that is proven effective against the neurologic form of equine herpes virus, equine herpes myeloencephalopathy (EHM). All current vaccines on the market are directed against the respiratory and abortive forms of equine herpes virus.
2. A current consensus amongst equine veterinary internists through the American Association of Veterinary Internal Medicine regarding vaccination for prevention of EHM does not exist.
3. In 2013, a pilot study involving a small number of horses suggested that vaccination with Pneumabort-K (a killed vaccine) every 60 to 90 days decreased the severity of neurologic signs in horses challenged with EHM. However, the results did not show statistically significant differences.
4. Based on this information, horses that are traveling frequently, exposed to new horses and environments, as well as those exposed to horses that travel frequently, may potentially benefit from vaccination with the Pneumabort-K killed vaccine every 60 to 90 days amidst periods of high travel and increased potential exposure.
Regardless of vaccination status, the major defense against any infectious disease is to practice excellent bio-security measures: do not share tack, equipment, or water buckets, prevent nose-to-nose contact, disinfect tack and equipment frequently, monitor for clinical signs and fever, and avoid traveling with any horse that is showing evidence of illness.
