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Seattle area equestrian center battles Equine Herpes, seven horses euthanized

The Gold Creek Equestrian Center in Woodinville, WA has been battling Equine Herpes virus 1 (EHV-1) infections in horses since mid-December, prompting the facility to be put under quarantine.


On December 15, 2017 the Washington State Department of Agriculture reported EHV-1 a 13-year old Halflinger gelding at the facility in King County, WA.  37 of 60 horses have now been tested with 16 horses confirmed positive for the Equine Herpes 1 neurotropic strain.  Seven horses have been euthanized due to Equine Herpesvirus Myeloencepalopathy( EHM).

Equine Herpes Virus (EHV-1) infection in horses can cause respiratory disease, abortion in mares, neonatal foal death and neurological disease. The neurological form of the disease is known as Equine Herpes Myeloencephalopathy (EHM) and may be caused by damage to blood vessels of the brain and spinal cord associated with EHV-1 infection. EHM is most often due to the neuropathogenic strain of EHV-1, but may occasionally be caused by the non-neuropathogenic strain of the virus.

EHV-1 is easily spread and typically has an incubation period between 2-10 days. Respiratory shedding of the virus generally occurs for 7-10 days, but may persist longer in infected horses. For this reason, a twenty-one day isolation period of confirmed positive EHM cases is recommended along with stringent biosecurity protocols. Similar to herpes viruses in other species, the latent form of EHV-1 can reactivate at a later date, but generally with a low viral load posing a low risk of infecting other horses. Humans are not at risk of contracting the virus, however humans can act as an indirect mode of transmission.

Treatment of horses include supportive care and anti-viral therapy.  The attending veterinarian is making morning and evening rounds at the barn and evaluating fevers and clinical signs.  The horse facility is still under quarantine and strict equine biosecurity in place.  At this time no other horse facilities are reporting new cases in the state of Washington.

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