Show season is upon us again. Remember show animals are exposed to more diseases as they are co-mingled with others. Vaccinations of these show animals are a must. Consult your veterinarian as to which vaccines are recommended.
This year the equine sector has already had cases of EHV-1 reported in a neighboring state. Kansas recently released a statement of a horse being euthanized due to EHV-1. This was the second horse to be euthanized following a barrel race in Omaha, Neb.
EHV-1 stands for Equine Herpes Virus-1. This virus affects only the equine species. Most commonly this virus causes abortion and respiratory disease. The abortions occur in the last four months of pregnancy. We do have a vaccine to prevent EHV-1 abortion. We give this vaccine, Pneumabort-K, at 5, 7 and 9 months of pregnancy. The respiratory form will have signs develop 1 to 3 days following infection and look like influenza. Horses with the respiratory form will run a fever, cough and have nasal discharge. The respiratory form of herpes has been the cause of death in yearlings and 2-year-olds. Both EHV-1 and EHV-4 have been responsible for respiratory infections in young horses. The neurological form can be due to both EHV-1 and EHV-4. However, most neurological forms seen are due to EHV-1 and are considered to be an uncommon manifestation of EVH-1.
The neurological form was responsible for an outbreak in 2011. This outbreak originated at the National Cutting Horse Association-Western National Championship in Ogden, Utah. This outbreak resulted in 90 confirmed cases with 13 deaths. At this time there have been no statements from USDA on the Omaha cases. Signs of neurological herpes include sudden onset of ataxia, paresis and urinary incontinences. It usually involves multiple horses that have a history of fever, respiratory disease, and/or abortion. The clinical signs usually appear 6-10 days post exposure.
At this time there is no vaccine to prevent the neurological form of this virus. During the 2011 outbreak, many veterinarians vaccinated with both the EVH-1 and EVH-4 at the same time in order to decrease the incidence of abortion and increase the immunity to the respiratory disease. It did appear to decrease the number of cases, but it was used at a time when the numbers of cases were decreasing. The intranasal vaccine also claims to have some protection of the paresis of EHV-1.
The only protection of EHV-1 is to use the vaccines we have, good biosecurity, and if the owner is scared of the EHV-1 outbreak then keep your horses at home.