CHEYENNE – The Johnson County horse premise, quarantined for Equine Herpes Virus Myeloencephalopathy since April 3, has been released by the Wyoming state veterinarian upon the fulfillment of all quarantine requirements. The source of the infection is unknown. However, during the month of March, it had been at college rodeo events at the Cam-plex in Gillette and Goshen County Fairgrounds in Torrington where it could have either contracted the disease or exposed other horses. Due to timely recognition and diagnosis on the part of the owner and attending veterinarian, the horse was isolated and no other outside horses were affected. There are currently no known cases of EHM in the state.
However, Wyoming State Veterinarian Dr. Jim Logan would like to remind Wyoming horse owners to continue to be diligent in regards to biosecurity measures for event horses and close monitoring for signs of sickness including fever and neurological deficits. According to him, there has been a marked increase in the number of EHM cases reported in the United States in recent years, including outbreaks at large horse facilities and events, racetracks, showgrounds, veterinary clinics, and boarding stables.
“The vast potential for exposure on such premises, and the serious nature of the disease, continue to cause significant concern amongst the animal health community and the US horse industry,” he said.
Logan explained that most horses have been exposed to equine herpes viruses (EHV-1) and remain lifelong carriers of the disease, periodically shedding with no clinical signs or re-activating and becoming sick during periods of stress. This is when outbreaks can occur and why identification and isolation of sick horses is crucial to controlling the disease.
EHV-1 is contagious and is spread by direct horse-to-horse contact; by contaminated hands, equipment and tack; and, for a short time, through aerosol dissemination of the virus within the environment of the stall and stable. Horses may appear to be perfectly healthy yet spread the virus via the secretions from their nostrils.
The initial clinical signs of the infection may be nonspecific and include fever of 101.5 degrees or greater. Fever may be the only abnormality observed. Horses with neurological disease caused by EHV-1 infection can soon become uncoordinated and weak, have trouble standing, and have difficulty urinating and/or defecating.
Logan said there are many steps horse owners can take to help prevent the spread of EHV-1, such as:
• Isolation of sick horses. This is the most important first step horse owners can take.
• Horses that have aborted or shown signs of fever, respiratory disease, or neurologic disease should be separated from healthy horses and examined by a veterinarian.
• Do not share equipment among horses on the facility. Since this virus can be spread from horse to horse via contaminated objects such as water/feed buckets or tack, equipment should not be shared among horses.
For more information on EHV-1 and/or EHM, call the Wyoming Livestock Board at 307-857-4140.