Following New Mexico’s recent ban on admitting horses from Oklahoma City’s Remington Park racetrack, the Kentucky state veterinarian has directed Kentucky tracks and their associated training centers to prohibit transport of horses that were at Remington Park on or after Nov. 12 without the Kentucky state veterinarian’s prior approval.
The restrictions come after two Remington Park racetrack barns containing 166 horses were quarantined after one horse tested positive for the neurologic form of equine herpesvirus-1 (EHV-1) on Nov. 12 and two additional horses tested positive on Nov. 21.
Kentucky officials will make decisions to admit horses from Remington Park to Kentucky tracks on an individual basis in consultation with the track concerned. Any approvals will be made only after testing and further evaluation of horses in question following their departure from Remington Park.
In the meantime, officials in Kentucky will continue to allow horses that meet the commonwealth’s normal entry requirements from Remington Park to enter Kentucky and be stabled on a private farm. Officials advise farms providing such stabling about the heightened risk these horses pose to resident herds, and to adopt heightened biosecurity procedures including isolation of new arrivals.
Herpesvirus is highly contagious among horses and can cause a variety of ailments in equids, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and EHM.
In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. In addition to fever, other common signs of EHV-1 infection in young horses include cough, decreased appetite, depression, and a nasal discharge. Pregnant mares typically show no signs of infection before they abort, and abortions usually occur late in gestation (around eight months) but can be earlier. Abortions can occur anywhere from two weeks to several months following infection with EHV-1.
Horses with the neurologic form (equine herpesvirus myeloencephalitis, or EHM) usually have a fever at the onset of the disease and might show signs of a respiratory infection. A few days later neurologic signs such as ataxia (incoordination), weakness or paralysis of the fore- and hind limbs, urine retention and dribbling, loss of tail tone, and recumbency (inability to rise) develop.
Herpesvirus easily spreads via nose-to-nose or close contact with an infectious horse; sharing contaminated equipment including bits, buckets, and towels; or clothing, hands, or equipment of people who have recently had contact with an infectious horse. Establish and maintain routine biosecurity measures, including hygiene and basic cleaning and disinfection practices, to help prevent disease spread.
Current EHV-1 vaccines might reduce viral shedding but are not protective against the neurologic form of the disease. Implementing routine biosecurity practices is the best way to minimize viral spread, and the best method of controlling the disease is prevention.