On December 7, 2018, the Pennsylvania Veterinary Laboratory in Harrisburg confirmed equine herpesvirus myeloencephalopathy (EHM) in a horse with hind limb ataxia. The horse tested positive for EHV-1 (G-strain).
As of December 10, two horses were affected and both horses have been euthanized at that premises.
The premises, a pleasure horse barn in Snyder County, Pennsylvania, has been quarantined by the Pennsylvania Department of Agriculture, Bureau of Animal Health. Eight horses remain on the premises and are being monitored for clinical signs of EHV-1 infection. Biosecurity precautions have been implemented to prevent the spread of the virus off of the premises. No additional clinical signs have been noted in the remaining horses.