EHV Outbreak

As you probably know, the outbreak of Equine Herpes Myeloencephalopathy, ”neurological Herpes,” that has been traced to horses that attended the National Cutting Horse Associations’ Western National Championships in Odgen, Utah, on April 30 ??? May 8 is spreading. Because of this, numerous horse events are cancelled. Additional affected horses are surfacing daily in many different Western states. Some farm owners are not allowing horse traffic in or out, and some are not even allowing farriers on the premises, for fear that they might transport the virus.

All owners of horses that attended this event — or may have had contact with horses that attended the event — are urged to be alert for early symptoms, such as lethargy and poor appetite. They should take their horse’s temperature daily for two weeks following the date of the possible exposure, and write down the results.

The neuropathogenic strain of the EHV-1 virus differs from the respiratory and abortion strain by a mutation in only one gene. That mutation allows the virus to reproduce more rapidly leading to blood and tissue levels that are 10 times higher than with other strains of EHV-1.

Horses with neurological EHV-1 do not necessarily show any respiratory symptoms, but their nasal discharges contain very high levels of the virus and they can spread it in this way.

There is no effective treatment for this virus, and current vaccines are not protective although there is preliminary evidence that Pfizer’s modified live vaccine may provide some protection.

If your horse was exposed, the first thing you’ll notice is a fever (approximately 102?° or more). Contact your veterinarian immediately and expect that your facility could be shut down for movement on and off the grounds until two weeks after all horses have ceased showing any fever. Infection with neuropathogenic strain of EHV-1 can be confirmed by PCR testing of nasal swabs and blood.

What did you think of this article?

Thank you for your feedback!