Although horses cannot be infected by the herpes zoster virus that causes shingles in humans, they can contract one of five strains of the equine herpes virus. In humans, the herpes virus can lay dormant in the body and later manifest as shingles. The equine herpes virus is like herpes zoster. Symptoms may appear immediately or years after the horse contracted the virus, although not all horses develop symptoms.
One of the most common strains of the virus, equine herpes virus-1, causes rhinopneumonitis in horses. This condition affects the respiratory system and can cause coughing, runny nose and fever. Pregnant mares who become infected may abort their baby. In addition, in some horses, the virus attacks the nervous system causing stumbling and urine leakage. The equine herpes virus-4 strain causes milder symptoms than equine herpes virus-1. Equine herpes virus-3 causes genital sores.
Two strains of the equine herpes virus -- equine herpes virus-2 and equine herpes virus-5 -- are found in most horses, but do not cause disease.
Treating the Equine Herpes Virus
Unfortunately, there is no cure or direct treatment for the equine herpes virus. The virus is highly contagious so infected horses should be isolated immediately.
Horses with mild illness may recover with rest alone. In more severe cases, horses may need anti-inflammatory medications, a sling to help them stand or fluids for hydration. Antibiotics may be necessary for horses who develop a secondary infection, although they will not treat the virus.
Although conclusive studies have not been done on horses, the drug used to treat herpes in humans, Acyclovir, may help reduce symptoms in horses. In addition, supplementing your horse's diet with the amino acid lysine may help slow virus replication.
Preventing Herpes Infection
Prevent herpes infection by vaccinating your horse against the disease every year. Horses at high risk, such as those in poor health or who travel frequently should be vaccinated every six months.
Isolate infected horses showing symptoms to prevent transmission of the disease. In addition, those handling the infected horse should not have contact with other horses as the virus can be spread on clothing.
If you are in contact with an infected horse, wash all of your clothing, including your boots, before coming into contact with other horses. Clean and disinfect any exposed stalls, trailers and buckets and dispose of any contaminated hay and bedding.
If a horse is returning from a show or a new horse is introduced to the barn, isolate them for 7 to 21 days to ensure they are not infected.