Equine Infectious Neurologic Diseases Table Topic (AAEP 2012)

Attendees discussed vaccinations for several infectious neurologic diseases, including EHM, WNV, and EEE.

Photo: Anne M. Eberhardt/The Horse

Veterinarians attending the equine infectious neurologic disease table topic at the 2012 American Association of Equine Practitioners' Convention, held Dec. 1-5 in Anaheim, Calif., focused on four continuing problems, including neurologic equine herpesvirus-1 (EHV-1/EHM) myeloencephalopathy, equine protozoal myeloencephalitis (EPM), West Nile virus (WNV), and other encephalitides. They also discussed Eastern equine encephalitis (EEE) and rabies.

The EHM discussion centered on diagnostic procedures and vaccine administration in the face of an outbreak. The take-home message was that real-time polymerase chain reaction (PCR) testing followed by virus isolation when possible is best for diagnosis. Attendees agreed that nonvaccinated horses with likely exposure to horses in an outbreak should be vaccinated, usually using a killed monovalent vaccine, although some discussion about using a modified live vaccine ensued.

The second area of focus on EHM centered on the importance of involving public officials to ensure all state and federal regulations are adhered to and that as much data about outbreaks can be captured for help with future outbreaks. Nicola Pusterla, DVM, PhD, Dipl. ACVIM, an associate professor in the Department of Medicine and Epidemiology at the University of California, Davis, briefly described the role of mules in an outbreak.

The EPM discussion centered on diagnostic testing using any of the available tests that have been validated by comparison to the gold standard, which remains a postmortem examination. Veterinarians agreed that regardless the test selected, the likelihood the horse has EPM might be increased when values are examined in both blood and cerebral spinal fluid.

Moving forward, attendees noted that the cost of vaccination appears to affect some owners' decisions to inoculate their horses against WNV rather than deadlier but less common diseases such as EEE. This has resulted in some horses contracting fatal disease, so owners need to be educated on the importance of vaccinating against diseases in their area of the country.

Attendees then briefly discussed rabies following a comment from Steve Reed, DVM, Dipl. ACVIM, of Rood & Riddle Equine Hospital, in Lexington, Ky., about the recent exposure he had to the disease while in Brazil.

This table topic was moderated by Steve Reed, DVM, Dipl. ACVIM, of Rood & Riddle Equine Hospital, in Lexington, Ky., and Nicola Pusterla, DVM, PhD, Dipl. ACVIM, an associate professor in the Department of Medicine and Epidemiology at the University of California, Davis.

About the Author

Stephen Reed, DVM, Dipl. ACVIM

Stephen Reed, DVM, Dipl. ACVIM, joined the Internal Medicine Service department at Rood & Riddle Equine Hospital in Lexington, Kentucky in Jan. 2007, after he retired from Ohio State University as an emeritus professor. His career has been predominantly dedicated to teaching with emphasis on Equine Neurologic Diseases.

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