Vaccinated horses can still develop the neurological form of the virus. Isolation of new animals, having all horseshows require health certificates, and taking care to wash hands and not share tack or grooming equipment can help to prevent outbreaks.
Some people say that horses age 5 and older are the most susceptible to the virus. Horses in this age group are often exposed to stress. The virus can get into the body and then become dormant or latent. When the horse is stressed, it can activate the “sleeping” virus, and the horse can begin shedding the more neurologic strains. The virus can become more virulent, resulting in increased fever, decreased circulation, and hemorrhage. If the virus gets into the spinal fluid, it can cause the neurological form of the disease. EHV-1 is very contagious. It is spread through the air, via nasal secretions, and from the walls and floor of a stall where a sick horse was kept. Not all horses with EHV-1 have a high fever. Some will only show an acute onset of neurological signs. Neurological signs can include difficulty in defecation and urination, inability to stand, and ataxia. PCR tests are very helpful in determining if the horse has EHV-1. Get the horse to your veterinarian so that blood and nasal secretions can be sent to the lab.
To help prevent EHV-1 virus in your barn, you may want to consider keeping the horses that go to horseshows separate from the rest of the population. Tack and grooming equipment should also be kept separate. Always wash your hands after petting or handle other people’s horses at shows. Isolate new horses to your barn for 21-28 days.
During an active outbreak, make sure that equine body workers and farriers wash their hands and wear some type of overcoat or lab coat that can be changed between barns. Have them use a footbath for their shoes. Most disinfectants will kill the virus. This includes: Bleach (4-8 ounces/gallon), Detergents, and Phenol based products.