SALEM, Ohio — Cases of a highly contagious and potentially fatal equine disease have been detected in Pennsylvania, but officials say they are not connected to the outbreak that has impacted more than 30 horses across the country.
Equine herpesvirus myeloencephalopathy was reported Nov. 27 in horses at a farm in Lancaster County, Pennsylvania. State ag officials said there were no known links to the EHM outbreak that began at a barrel racing event in Waco, Texas.
As of Dec. 1, the Equine Disease Communication Center confirmed 33 cases of EHM, the neurological condition linked to the equine herpesvirus-1, tied to the Women’s Professional Rodeo Association World Finals and Elite Barrel Race event held in Waco, Texas, from Nov. 5 to Nov. 9.
Horses in Texas, Oklahoma, Louisiana, Colorado and New Mexico have been impacted. At least four horses have been euthanized as a result of this infection.
Another 13 cases of EHV-1 without neurological signs tied to the Waco outbreak have been detected in Washington, Arizona, Texas and Oklahoma.
In the Lancaster, Pennsylvania, case, three horses showed clinical signs, and one was euthanized due to the severity of the disease before it was tested. The other two horses later tested positive for EHM.
A case of EHV-1 was also confirmed in Madison County, Ohio, on Nov. 23, but it was not linked to the Waco outbreak.
Local stables and arenas in the tri-state area have tightened up their safety measures and canceled events until the outbreak is contained. Horses can shed the virus during the incubation period, 2-10 days, before developing clinical symptoms, and can continue shedding the virus after they recover.
Exposed horses should be isolated for 21 days after last-known exposure, and isolation should include restricted access to other horses, avoiding shared equipment or personnel, and using appropriate protective barriers, according to the Ohio State University Veterinary Medical Center.
Equine herpesvirus commonly causes respiratory disease, but some strains cause outbreaks of the rare neurological disease known as EHM. Symptoms of EHV-1 can vary widely. Some horses may show mild signs like nasal discharge, a fever of 102.5 F or greater and coughing.
Other symptoms include becoming lethargic or developing worsening neurological issues, which occur as a result of a lack of blood flow and resulting damage to the brain or spinal cord.
Symptoms can include stumbling, incoordination, loss of tail tone, hind-limb weakness, head tilt, difficulty standing and urine dribbling.
In most cases, 60% to 70% of affected horses recover with treatment and supportive care, according to the Equine Disease Communication Center, but veterinary evaluation and isolation of exposed or affected horses is crucial.
Related content:
Concern grows as more horses test positive for neurological disease