Equine Herpesvirus
If a horse was potentially exposed, vaccinating now can cause more confusion than clarity because it can interfere with how the immune system responds during the early stages of infection. For healthy horses with no known exposure, a booster is still a smart step in lowering risk - Kile S. Townsend DVM
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Everything You Need To Know About EHV-1
It happens every year. First, it’s a 2-year-old that’s feverish and coughing. Then, a pregnant mare loses her foal. A week later, a seasoned sport horse becomes incontinent, falls down, and never gets back on his feet. Suddenly, you have a barn full of horses with fevers—and it seems like as soon as one gets better, two others get worse. If you’re lucky, none of the animals have moved to other locations recently where they might infect other horses. What’s going on? Quite simply, an infectious microbe has declared war. Equine herpesvirus type 1 (EHV-1), also known as equid alphaherpesvirus-1, has awakened from the depths of its hiding place in the immune or nervous tissues of one horse, replicated…Featured
Latest Equine Herpesvirus Alerts
Testing and quarantining affected horses in isolation is the primary way to control the disease. Vaccines are available but do not completely prevent any form of the disease.
EHV Outbreak - What Horse Owners Need to Know Right Now
One of the most important things owners can do right now is stay alert to even subtle changes in their horses. Early signs like a mild fever or nasal discharge might not seem alarming on their own, but they can be the first indicators of EHV exposure. Catching those signs early gives your veterinarian the best chance to intervene and limit the risk to other horses on the property.
Articles of Interest
Equine Herpesvirus (Rhinopneumonitis) Vaccination Guidelines
Primary indications for use of equine herpesvirus vaccines include prevention of EHV-1-induced abortion, and reduction of severity and duration of signs of respiratory tract disease (rhinopneumonitis) in foals, weanlings, yearlings, young performance and show horses that are at high risk for exposure.
Equine Herpesvirus in Horses
Increasingly, various equine events are experiencing quarantines and restrictions of equine movements due to outbreaks of equine herpesvirus. Equine herpesvirus (EHV) is a common viral disease of horses and is known to infect horses worldwide. How common is EHV? It is estimated that most horses have been infected by two years of age, with initial exposure and infection thought to occur between the mare and the foal. Economic losses from EHV include pregnant mares that may experience abortions, and the interruption of training in young horses. The form of the disease that is of most concern is the neurologic form, which often results in infected horses being euthanized.
Equine Herpesvirus Myeloencephalopathy (EHM) Outbreak
Equine herpesvirus-1 (EHV-1) is the virus causing this outbreak. While EHV-1 most commonly causes respiratory disease, some strains cause outbreaks of neurologic disease. EHV-1 causes neurologic signs as a result of inflammation of the blood vessels and activation of blood coagulation within the brain and spinal cord. Neurologic signs occur as a result of a lack of blood flow and resulting damage to the brain or spinal cord; this disease manifestation is known as Equine Herpesvirus Myeloencephalopathy (EHM).
Understanding the recent equine herpesvirus (EHV) outbreak
Most EHV-1/EHM–positive horses can be safely managed on-farm as long as they remain standing, ambulatory and able to eat, drink, urinate and defecate normally. In these cases, veterinarians can provide supportive care and monitor for changes. Mizzou’s equine internal medicine clinicians are available to support referring veterinarians with treatment guidance, biosecurity recommendations and testing through the VMDL.
Resources
Risk-Based Equine Vaccines: Equine Herpesvirus
None of the available vaccines have a label claim to prevent the neurologic form of EHV-1 infection. It has been suggested that vaccines may assist in limiting the spread of outbreaks of EHM by limiting nasal shedding of EHV-1 and dissemination of infection. For this reason some experts hold the opinion that there may be an advantage to vaccinating in the face of an outbreak. If this approach is pursued, only afebrile and asymptomatic horses should be vaccinated and protection against clinical EHM should not be an expectation.
