Prevent EHV infection

Farm Forum

PIERRE – As spring rapidly approaches, Dr. Dustin Oedekoven, South Dakota state veterinarian, reminds horse owners to prevent the spread of equine herpesvirus (EHV).

EHV has historically been found in South Dakota, and is transmitted between horses in close contact. Three forms of the disease are recognized: respiratory, reproductive and neurologic. The respiratory form is the most common, with symptoms of coughing, nasal discharge and a high fever. The reproductive form causes abortion in mares.

Horse owners are encouraged to continue consulting their veterinarians on ways to protect their animals. The virus has no effect on people or other livestock. Affected horses develop high fevers, lose coordination and may die. Once a horse is infected with the neurologic form, treatment is limited, including supportive care, antiviral drugs and anti-inflammatories.

Prevention of EHV begins with a solid biosecurity plan. Horse owners can minimize spread of EHV by implementing a 21-day isolation policy when adding new horses or returning horses to established herds. Buckets and other items used to feed and water horses or groups of horses should be cleaned and disinfected regularly. Horses with fever or recent known exposure should stay at home.

Vaccines effective in preventing respiratory and reproductive EHV are widely available and should be administered as directed by the owner’s veterinarian. Often this means at least twice every year, with horses that travel to events boostered as often as every 3 months. Horse owners are encouraged to visit with their veterinarian to determine a vaccination program best suited to their individual needs.

Dr. Oedekoven strongly encourages organizers and planners of equine events to seek the advice of veterinary professionals for guidance on disease prevention. Horses that have been vaccinated less than 7 days or greater than 90 days prior to an event may be at higher risk for spreading EHV. In addition to consideration of standard health requirements, protocols should be developed prior to the event to address potential isolation and quarantine procedures in case of an outbreak.

Keep your horses safe and healthy. Employ biosecurity to reduce the spread of equine herpesvirus. For more information, visit