The California Department of Food and Agriculture (CDFA) reported that Equine Herpes Myeloencephalopathy (EHM), caused by Equine Herpes Virus (EHV-1), has been confirmed in 10 horses in California, in Kern, Placer, Stanislaus, Amador and Napa counties.
One horse in Kern County was euthanized after showing severe neurologic signs often associated with the disease.
All of the infected horses recently attended the National Cutting Horse Association’s Western National Championships in Odgen, Utah on April 30 – May 8, where they were most likely exposed to the virus.
According to Karen Unger, a veterinarian at Pioneer Equine Hospital in Oakdale, EHV-1 is a respiratory virus and it can lead to a horse’s death in some cases.
Equine Herpes virus is a contagious disease and may spread quickly among horse populations. EHV-1 is not transmissible to humans. Horse-to-horse contact, aerosol transmission, and contaminated hands, equipment, tack and feed all play a role in disease spread.
Early symptoms of EHV-1 include a rectal temperature of 102 degrees and above. Further advanced symptoms include Horses infected with the neurologic strain of EHV-1, may show any of the following clinical signs: nasal discharge, lack of coordination, hind-end weakness, lethargy, urine dribbling and diminished tail tone.
All California horses that have been in contact with an infected horse and show signs of disease or test positive for EHM will be placed under a CDFA quarantine in order to limit spread.
“We don’t anticipate seeing any cases here and if we did we have the horse isolated either at home or in a quarantine facility at UC Davis,” said Unger.
The California Department of Food and Agriculture has contacted all 54 exhibitors from California who participated in the Ogden, Utah event and asked them to isolate and monitor their horses for clinical signs of EHV-1.
There is no specific treatment for the virus.
“There is only supportive treatment, the best thing you can do is isolate the horse and stop the spread” said Unger.
Treatment may include intravenous fluids, anti-inflammatory drugs and other appropriate supportive treatment. Immediate separation and isolation of identified suspect cases and implementation of appropriate biosecurity measures are key elements for disease control.
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