Experts have reported that the outbreak of Equine herpesvirus myeloencephalopathy (EHM), the also referred to as Neurotropic Equine Herpes Virus -1 (nEHV-1), originated at the National Cutting Horse Association’s Western National Championships in Ogden, Utah, held April 29 – May 8, 2011.
This is a mutant strain of the highly contagious and potentially fatal disease, for which there is no vaccine. Neurological signs such as nasal discharge, hind-end weakness, lethargy and trouble urinating, appear due to damaged blood vessels in the brain and spinal cord associated with EHV infection. The incubation period is between two to six days following exposure, but this can vary. There is no specific course of treatment for the disease, but symptoms can be treated with, for example, intravenous fluids and anti-inflammatory drugs.
An updated posted on the National Cutting Horse Association’s website reports that confirmed cases have been documented in Colorado, Utah, California, Washington, Idaho, Arizona and Alberta. Other reports indicate that there have been a total of 15 confirmed cases and at least 13 suspected cases in the U.S. and two more in Canada.