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Reining Horse Tests Positive For Disease Linked to EHV-1

A reining horse that attended a show last month in Oklahoma has tested positive for Equine Herpes Myeloencephalopathy (EHM), the neurologic disease linked to Equine Herpes Virus (EHV-1). Officials say the horse from Montgomery, Texas, was confirmed positive on Tuesday, April 9.

The Texas Animal Health Commission (TAHC) announced Wednesday, April 10, that the positive horse attended a reining event in Ardmore, Oklahoma, the week of March 18. The event calendar on the National Reining Horse Association website lists the History & Champions Derby and Ride & Slide at the Hardy Murphy Coliseum in Ardmore during that week. According to a news release, which did not identify the reining event, Commision staff have been in contact with the Oklahoma State Veterinarian to ensure event participants were notified and enhanced biosecurity measures are taken.

The horse that tested positive has not traveled to any other event since the one in Oklahoma, the TAHC stated. The animal is under the care of a Brazos County veterinary hospital. Officials say it was quarantined after showing signs of ataxia (a lack of coordination) and other neurologic signs consistent with EHM.

Click here for more information on EHM.

While the risk of exposure to the virus was likely low at the reining event, officials at the Commission say owners of horses potentially exposed are encouraged to take precautions. Exposed horses should be isolated and have their temperatures monitored twice daily for at least 14 days after their last known exposure. If an exposed horse develops a fever or other signs consistent with EHM, diagnostic tests may be performed. Owners should work with their veterinary practitioners to establish appropriate monitoring and diagnostic plans for any potentially exposed horse(s).

One of the most common clinical signs of EHV-1 is fever, which often precedes the development of other signs. Respiratory signs include coughing and nasal discharge. Neurologic signs associated with EHM are highly variable, but often the hindquarters are most severely affected. Horses with EHM may appear weak and uncoordinated; urine dribbling and loss of tail tone may also be seen. Severely affected horses may become unable to rise.

Officials say it is important to remember these signs are not specific to EHM and diagnostic testing is required to confirm an EHV-1 infection. Many horses exposed to EHV-1 never develop clinical signs. If a person suspects their horse has been exposed to EHV-1, they should contact their local veterinarian.

Enhanced biosecurity measures also were implemented recently at two other Western performance horse events. Prior to the recently concluded National Reined Cow Horse Association (NRCHA) Stakes, officials at the host site — the South Point Equestrian Center — took extra precautions in the wake of EHV-1 positives in the state of Nevada. The upcoming National Reining Breeders Classic will have enhanced biosecurity requirements for horses entering its host facility as a result of a jumping horse getting sick with strangles earlier this year.

Click here for more information about equine biosecurity.

Additional information and updates about this incident and other horse-related disease incidents in the country is available at the Equine Disease Communication Center (EDCC) website, www.equinediseasecc.org/alerts/outbreaks.  

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