One horse has died and four others from the same stable have tested positive for a neurological form of Equine Herpes Virus (EHV-1) in Oregon.
All horses on the property in Lane County have been quarantined and those showing symptoms of the disease are being treated.
There is no indication that the virus has spread to other horses beyond those being quarantined.
State veterinarian Dr Brad LeaMaster praised the quick work by local veterinarians and Oregon State University’s Veterinary Diagnostic Laboratory in detecting the virus quickly and taking steps to limit any spread.
“At this point in time, the investigation shows that this is an isolated incident confined to the animals now under quarantine,” said LeaMaster, who is attached to the Oregon Department of Agriculture.
“Equine veterinarians in the state are well aware of this virus and are trained to take the proper steps when a horse is showing symptoms.”
LeaMaster said the horses in Lane County exposed to the virus have not been moved from the property in more than two months, well before EHV-1 was detected.
EHV-1 is not transmissible to people. The virus is naturally occurring and widespread in the equine population.
It is a common virus that may lie dormant for long periods of time and then re-activate during a period of stress, which can result in clinical disease.
EHV-1 can cause respiratory disease, abortions in pregnant mares, neurologic disease, and, in severe cases, death.
The most common way for EHV-1 to spread is by direct horse-to-horse contact. The virus can also spread through contaminated equipment, clothing, and hands. Symptoms include fever, decreased coordination, nasal discharge, urine dribbling, loss of tail tone, hind limb weakness, leaning against a wall or fence to maintain balance, lethargy, and the inability to rise.
While there is no cure, the symptoms of the disease may be treatable.
There are 10 horses at the Lane County stable, with four of them confirmed as having the virus. The horse that died had originally been purchased from an owner in Benton County. The previous owner has been contacted and reports no signs of illness in any of their horses.
“The Lane County stable owner and all horse owners have been very cooperative and supportive of the disease control actions taken,” LeaMaster said.
“A neurologic EHV-1 diagnosis certainly gets the attention of equine veterinarians and horse owners. We have had occurrences of the disease in Oregon in the past. I’ve noticed what seems to be a higher degree of awareness of the EHV-1 disease with horse owners than there was just a couple a years ago.”