EHV-1 Updates as of March 12

This article originally appeared on Eventing Nation. 

In an effort to compile as much information concerning the European EHV-1 outbreak and the crop of cases scattered about the U.S., we’ll be continuously updating this post with new cases, updates from the FEI and USEF, and biosecurity measures that have been implemented at events around the country. We’ll make every effort to keep tabs on this important information but can always use help; please email with any verified information that we may have missed.

While there has not been a mass lockdown at most facilities that have seen cases, we encourage all owners to carefully consider their horses’ movements. EHV-1 is a highly transmissible and aggressive virus, and the incubation period of anywhere from 2 to 10 days means a traveling horse may be a carrier, unbeknownst to the owner.


The Equine Disease Communication Center is providing updates on reported cases on a regular basis. You will need to select the form of EHV you want to search for in order to run the locator. At this time, there has been no connection made to the outbreak stemming from Spain that has shut down FEI competitions in Europe.

On March 11, new cases have been reported in New York and Kentucky.

On March 10, a new case with 45 potential exposures was reported in Los Angeles, Ca. Previous reported cases are from the states of FloridaMarylandPennsylvaniaOntario, and Quebec.


The latest timeline updates and figures from the FEI can be found here. As of March 11, there have been 12 confirmed deaths from EHV-1 in Europe. Meanwhile, horses are set to begin leaving the venue in Valencia, where they have been quarantined since February.

US Equestrian held an informational webinar on March 5 to educate members on the EHV-1 virus and biosecurity precautions to take. It can be viewed here.

A previous US Equestrian press release outlines biosecurity measures horse owners and riders can take. You can view the release here.


French Equestrian Federation Suspends All Competition in Response to EHV Outbreak

FEI Cancels All Competition on European Mainland Through 3/28 Due to EHV-1 Outbreak

Updates on EHV-1 European Outbreak + One Case Reported in Ocala

Update on Venturing Hills Farm EHV-1 Outbreak & How You Can Help

EHV-1 Death Reported at New Bolton in Chester County, PA [Updated March 6]

EHV-1 Updates: Ocala Has Two Confirmed Cases, FEI Continues to Monitor European Outbreak

Equine herpesvirus type 1, or rhinopneumonia, is a relatively common respiratory condition that’s spread through horse-to-horse contact. But this doesn’t necessary mean the horses need to be in close enough proximity to touch noses – aerosol droplets or nasal discharge can contaminate surfaces, such as grooming tools, buckets, and even clothing and hands, spreading the virus quickly and efficiently among a number of horses. For this reason, it can become hard to control very swiftly – particularly as carriers may not show any symptoms while actively spreading the virus over its 2–10 day incubation period.
Although EHV-1 can lead to abortion in pregnant mares or ongoing respiratory issues, it’s a largely innocuous virus that an enormous amount of horses will come into contact with at some point or another. So what makes this outbreak different? Simple: it’s the progression into a neurological form of the disease, known as Equine Herpesvirus Myeloencephalopathy, or EHM. This progression happens when EHV-1 progresses into the bloodstream, causing inflammation in the microvasculature. This, in turn, can restrict blood flow to areas of the spinal cord, leading to neurologic disease.
EHM is a very rare and incurable form of EHV-1, which can show up in a multitude of ways: some horses may experience a biphasic fever, which has two ‘spikes’, a sudden lack of coordination, limb weakness, loss of balance and inability to stand normally, inability to urinate effectively, or depression. Though there’s no cure, EHM-positive horses can be administered NSAIDs such as bute or banamine to reduce fever and pain. Some horses do go on to recover from EHM – often with lingering neurological deficits – but the fatality rate is high at 30%.
Though there’s no vaccine for EHM, it’s most often caused by EHV-1, so ensuring your horses’ vaccinations are up to date is the most effective way of protecting them against an outbreak. Implementing a robust quarantine strategy when introducing a new horse to your property, too, is essential: keep the new horse separate for ten to fourteen days, limiting the number of people who have access to it and ensuring that all tools and clothing are thoroughly disinfected, and hands washed, before coming into contact with another horse.