Update on Local EHV-1 Cases

HorsesOn June 18, 2015, the California  Department of Food & Agriculture (CDFA) announced that a case of Equine Herpesvirus Myeloencephalopathy had been confirmed in San Joaquin County.

Other cases have been reported in Riverside, Santa Cruz and Monterey counties.  Click here for more details on these cases.

The 13 year old Quarter Horse mare resides in San Joaquin County and tested positive for the neuropathogenic strain of EHV-1.  She did not attend Mule Days in Bishop, CA from May 17-26, 2015 but was exposed to two cohort mules after they arrived home from Mule Days.  The mules were asymptomatic for EHV-1.

The Quarter Horse mare exhibited symptoms compatible with EHV-1 beginning on June 5th including lethargy, fever, stocking up of her hind limbs and severe lack of coordination in her hind limbs.  The mare was euthanized on June 14th. The affected premises are home to 10 horses and mules and at this time there are no other affected equids (horses, donkeys or mules) on this property.  The owner has been monitoring temperatures 2 times per day on all of the horses and mules.  This mare had not received any EHV-1 vaccinations in the past two years.  This location is under CDFA quarantine.

Equids diagnosed with the neuropathogenic strain of EHV-1 are much more likely to develop neurologic signs than those equids diagnosed with the non-neuropathogenic strain of EHV-1.  By definition, equids infected with EHV-1 that develop neurologic signs are considered EHM cases.  EHM is considered a reportable disease in California and must be reported to regulatory officials within 48 hours.  An investigation has been initiated and owners with potentially exposed horses will be contacted.  Owners of exposed horses are asked to monitor their horses for clinical signs and take temperatures twice daily. CDFA will continue to monitor the situation.

Recommendations for Participants at Equine Events

CDFA reminds horse owners traveling with horses to participate in an equine event, that there is always disease risk when horses of unknown health status are commingled for a show or competition.  CDFA strongly recommends that horse owners practice proper biosecurity when attending an equine event.  Compliance with basic biosecurity practices is an important factor in reducing risk of exposure to all contagious equine diseases.

Basic biosecurity measures to decrease potential disease spread at equine events include:

  • Limit horse-to-horse contact.
  • Limit horse-to-human-to-horse contact.
  • Avoid use of communal water sources.
  • Avoid sharing of equipment unless thoroughly cleaned and disinfected between uses.
  • Monitor your horse for clinical signs of disease and report any temperature over 102°F to a veterinarian.

Read our recent blog for more information on this virus and learn how you can take preventative measures.

If you are concerned your horse may have been exposed to EHM, contact Hunter Stallion Station (916) 687-6870, or your equine veterinarian immediately.  Please share this message with other horse owners to help prevent further spread of the virus.