Viruses are a difficult and challenging part of life. We are now into the cold and flu season, when reminders about immunizations and staying home when sick abound. Many viruses cause issues in livestock production such as PRRS in swine, HPAI in poultry, IBR/BVD in cattle, to name a few, but for equids, equine herpesvirus (EHV) has been in the news again recently. Owners of horses, donkeys, mules, etc., need to be vigilant with this virus, particularly if there has been exposure to other animals at events or new animals enter your premises.

Equine herpesvirus is a family of nine viruses named by numbers. EHV-1, the virus associated with the ongoing outbreak, is most commonly associated with respiratory tract infections. EHV-1 is also associated with neurologic disease and abortion. Upwards of seventy percent of horses are infected with EHV-1 as youngsters and carry it with them for the remainder of their lives.

Respiratory illness caused by EHV-1 often presents with fever, clear nasal discharge, and coughing. Horses will spread the virus before they show outward signs that they are sick. Pregnant mares may experience sudden late-term abortion of the fetus. In some horses, the virus progresses to equine herpes myeloencephalopathy (EHM), causing incoordination, hind-limb weakness, reduced tail strength, dribbling urine or sudden inability to stand.

Equine herpesvirus is spread from horse to horse through nasal discharge, aerosolized droplets from coughing and contact with contaminated surfaces. Even though humans cannot contract the disease, they can accidentally spread the virus between horses on their hands, clothing, or equipment. Veterinarians advise that any horse showing signs of illness should be isolated from all other horses immediately, and local veterinarians contacted. Quick assessment of possible exposure and strict quarantine procedures are essential in stopping further spread of the virus.

Commercial vaccines are available for EHV. While vaccination for EHV is known to be beneficial in reducing respiratory and reproductive disease, they are not reliably protective against EHM. Kansas Animal Health Commissioner Dr. Justin Smith has offered that horse owners should follow a set of biosecurity measures to protect horses including:

• Isolating horses that have been exposed to EHV-1 or are returning from events for 14 days.

• Checking the horse’s temperature twice daily and acting quickly if a fever is detected. A normal temperature ranges from 99 degrees Fahrenheit to 101.5 degrees Fahrenheit.

• Keeping all horses’ EHV-1 vaccinations updated; booster shots are recommended.

• Disinfecting water buckets, brushes, halters, bits, bridles, clothes, and boots after exposure at other facilities or events.

• Minimizing contact between horses, such as avoiding nose-to-nose interactions and using barriers or extra stall space at events.

• Changing clothes and boots after returning from events and never sharing equipment between horses.

• Checking with state animal health officials before traveling to out-of-state events. Some states have their own additional requirements, such as recent health papers.

Kansans who suspect an outbreak of EHV-1 or EHM should notify the Kansas Department of Agriculture’s Division of Animal Health at 785-564-6601. The Equine Disease Communication Center — https://equinediseasecc.org/ — has a wealth of current information on EHV.