LSU Vet Med Treating Three Texas Horses Quarantined with Confirmed EHV-1
Cases of Equine Herpesvirus-1 (EHV-1) has been confirmed by equine veterinary clinics in Texas, with cases traced to a recent equine competition in Waco. Three horses from Texas that participated in that event are currently quarantined at the LSU School of Veterinary Medicine Veterinary Teaching Hospital (VTH) and receiving treatment for confirmed EHV-1. The owners of these horses were given special permission by the Texas and Louisiana state veterinarians to cross state lines because isolation facilities in Texas are full, and LSU Vet Med has the next closest respiratory isolation unit. Quarantined horses are being housed in the isolation unit and pose no risk to animals in the rest of the VTH, and the equine hospital will remain open for appointments and emergency cases.
Diagnosis
Nasal swabs and blood samples from the horses were submitted to LSU Diagnostics (Louisiana Animal Disease Diagnostics Lab) for a diagnosis. A real-time polymerase chain reaction (PCR) assay was performed on specimens for detection of EHV-1. This method of testing is highly sensitive and specific with a rapid (one day) turnaround time for results.
What is EHV-1?
EHV-1 is a virus that spreads from horse to horse through contact with nasal discharge and aerosol droplets; it can also spread through contact with contaminated surfaces such as stalls, water, feed, tack, and vehicles, and people can spread the virus through contaminated hands, clothing, and equipment. EHV-1 predominantly causes respiratory signs but can cause other issues such as neurologic disease and abortion in pregnant mares.
Vaccine and Prevention
There is no vaccine to protect against the neurologic form of the disease, but there are vaccines to protect against from the respiratory and abortion forms of the disease. The best way to limit spread of the disease is to quarantine horses that may have been exposed to infected horses and clean and disinfect surfaces, clothing, and equipment to reduce the chance of transmission.
Prognosis
EHV-1 is not typically fatal, but horses that are severely affected may need hospitalization and severe cases of the neurologic form can potentially be deadly.
Signs
Clinical signs include
Fever
Nasal discharge
Enlarged lymph nodes
Lethargy
Late-term abortion (up to two months following infection)
Neurologic disease (signs include inability to stand, incoordination, urine dribbling)
If you suspect you have a horse that has developed the neurologic form of EHV-1, LSU VTH requires an initial assessment by your veterinarian to determine if it is able to be treated and quarantined on the property or if it requires referral to LSU. Many horses with neurologic EHV-1 can be successfully treated and quarantined on their property. Only severe cases should be referred to a veterinary hospital with a quarantine facility capable of handling contagious respiratory diseases, such as at LSU VTH. Once the isolation facility is at capacity, no additional cases will be able to be accepted to the VTH until stalls in the isolation building become available again.
Treatment
Horses with EHV-1 can be treated with supportive care and anti-inflammatory medications. Drugs may also be necessary to reduce fever and improve appetite. Antiviral medications may be needed for the neurologic form of EHV-1 and are best utilized when administered to exposed horses before they onset of clinical signs. Owners should contact their veterinarian to discuss treatment options.
“Owners that suspect a horse has been exposed should contact their veterinarian and quarantine the horse and any horses that have been exposed to that horse,” said Rose Baker, BVMS, DACVIM (LAIM), associate professor of equine medicine. “Your veterinarian can submit samples to LSU Diagnostics to determine if a horse is shedding EHV-1 into the environment.” Dr. Baker’s clinical and research interests relate to neurologic diseases in horses, critical care, and internal medicine.
Contact
For questions about EHV-1 testing, please call LSU Diagnostics at 225-578-9777 or go to laddl.org. If you or your veterinarian need to speak to an equine specialist at LSU Vet Med, please call 225-578-9500. Information about the LSU Vet Med VTH is available online at lsu.edu/vetmed under Hospital.
