The equine community is dealing with the emergence of Equine Herpesvirus Myeloencephalopathy (EHM), which is also known more simply as Equine Herpes Virus (EHV).  EHV is like other herpes viruses in that there are multiple forms of the virus that present clinical symptoms.  One variant produces respiratory symptoms while others can be neurologic, and some forms can cause abortions.  There are vaccines available for EHV-1 and EHV-4 but neither are effective in prevention of the neurologic variant.

This outbreak has been traced back to the Women’s Professional Rodeo Association World Finals and Elite Barrel Race that was held in Waco, TX on November 5^th to 9^th.  In the weeks following the event, the virus was reported in 6 states with 27 horses affected. 21 of those cases have presented with the neurologic form.   The equine disease communication center (https://equinediseasecc.org) is reporting one Ohio case from November 23^rd.  As a result, the organization’s event that was scheduled for November 17^th to 22^nd in Guthrie, OK was cancelled.

Horses affected by EHV can show respiratory symptoms such as fever (>101.5), clear nasal discharge that can transition to a yellow color, and lethargy/depression.  There is also a possibility of neonatal death and late-term abortion.  The neurologic symptoms include weakness in the hindlimbs, swelling of the limbs, difficulty urinating or defecating, loss of tail tone, and dog-sitting posture.  The virus is passed through direct animal contact, airborne transmission, and indirect transmission by people or animal husbandry equipment.  Once exposed the virus can show symptoms within 24 hours but are more typically in the 4 -6 day range.  Anyone whose horse is showing any of these symptoms should contact the veterinarian immediately.  The virus is not transmittable to humans and thus there is no human health threat.

There is no direct cure for the virus.  Affected animals are given supportive care involving intravenous fluids and anti-inflammatory medications.  Antiviral medications are commonly considered for treatment but there is no clear-cut evidence that they work.  It is estimated that 70-80% of affected horse can recover but those with severe neurologic symptoms are at greatest risk.

This EHV outbreak is another example of the importance of biosecurity.  Livestock shows and other events are an important component of the industry for youth and adults.  While it is rewarding to showcase the skills of the animals and their exhibitors, the commingling of animals from a multitude of areas carries the risk of disease transmission.  Regardless of what species of animal you show, and this would also include pets such as dogs and cats, you should implement precautions at the shows and once you come back home.

While at a show, it is difficult to implement all the established principles of biosecurity.  You should still take every precaution to protect your animals.  This would include:

• Have your animals up to date on all their vaccinations.
• Do not allow neighboring animals to have access to your animal’s feed and water
• Do not share show equipment with other exhibitors, and if you do sanitize it before using it with your animals again.
• Regularly clean your feeding and water equipment while at the show.

When you come home you should:

• Quarantine your show animals away from your other animals for a minimum of 30 days.  In the case of EHV, most recommendations are a 21-day quarantine, but 30 days is the practice norm.  These animals should be inspected a couple of times each day but should be the last group you visit each time.  The quarantine area should prevent nose to nose contact with your other animals and be at least 30 feet, and down wind, from your other animals.  The animal husbandry supplies used in the quarantine area should not be used with your other animals.
• Clean and sanitize all show equipment
• Clean and sanitize your trailer
• Launder all the clothing you wore while at the show, separate from your other laundry.  You should consider using a color-safe bleach product and high temperature dry after washing.

As we enter the holiday season, our Extension programming slows down until we enter the new year.  Frank and I are currently finalizing our winter programming schedule and will be releasing that information in the near future.  One way to stay up to date on our programming schedule is to sign up for the OSU Extension ANR Ag Quarterly Newsletter.  The newsletter is produced four times each year, and the next edition will be sent out the first week of January.  As always, I wish you a safe and productive conclusion to the harvest season.  If you have any questions, or would like to sign up for our newsletter, please feel free to contact me at the OSU Extension office in Wayne County at 330-264-8722 or email me at yost.77@osu.edu.

This article was previously published in The Daily Record.