Thursday, May. 23, 2024

Living Through An Outbreak: One California Barn’s EHV-1 Diary



By now, many people have heard what is happening on the West Coast amid a serious outbreak of EHV-1, but that story feels very different for those of us on the frontlines in Southern California. The California Department of Food and Agriculture’s website, along with its testing and official counts for infected horses, is accurate, but days behind what many of us here are going through.

While EHV-1 outbreaks do occur almost every year, they are generally manageable, especially on properties with adequate space to quarantine horses. It is in this regard that Orange County is already at a disadvantage. The majority of the county’s horse population lives in just three large-scale facilities: one private facility of about 80 horses and two large public stables, one with about 350 horses (where our business is based), the other with close to 500 horses. Due to the high cost of land and other factors, turnout at these large-scale equine properties is incredibly limited compared with most places across the country. There are no rolling hills of paddocks; there are arenas, plus many box stalls, pipe stalls and small turnout arenas for 10- to 20-minute use at a time. Horses will work in an arena, or turnout, some do go on trail rides, and then for the most part they return to their stalls.

Our program consists of 30 privately owned horses and riders who are in training under John Berney Equestrian. We only have control over these 30 horses in our program at the facility where we operate. The rest of the horses at this facility are under a number of other trainers or are privately owned and managed by their owners. The same is true with the neighboring properties, which are home to many trainers and under different management.

Five horses in our program attended the LA February Show put on by West Palm Events at Los Angeles Equestrian Center from Feb. 16-20. Before our horses left for the show, we became aware of cases of EHV-1 at Desert International Horse Park but were assured by West Palm Events that no horses that had been at DIHP would be allowed to come to LAEC. With horse show management ensuring no horses from the desert would be permitted, we felt safe attending.

This is what happened next:

EHV Diary nose

An EHV-1 positive horse in quarantine at John Berney Equestrian. Photos Courtesy Of Nina Thornton

Sunday, Feb. 20
On the last day of the LA February show, West Palm Events announced the cancellation of the LAXtra show that was scheduled for the following week at LAEC. In the same announcement, they announced they had learned of three horses that showed in the desert also attended LA February, saying in an email the horses “had been at DIHP, returned to their home barn, and then came to our show after five days of isolation instead of seven days. As soon as we became aware, we notified the trainers, and those horses left the property that same day.” We would later learn that trainers brought horses that showed at Desert Circuit IV, Feb. 8-13, just four days before coming to LA February.

Later that day, West Palm Events sent a second email saying, “This afternoon, we were informed of a horse with an elevated temperature. This horse was stabled in Barn 1. At this time, the horse is isolated, and we are awaiting test results.”

Our horses arrived home late the same afternoon and we decided to voluntarily quarantine them in their stalls for seven days, even though they had not been in the same barn as the horse with an elevated temperature or the horses that had shown in the desert. One of our horses, who normally lived in a pipe stall, which could allow nose-to-nose contact with other horses, was quarantined in a box stall, with the support of our facility management.

Tuesday, Feb. 22
West Palm Events sent an email saying they had been notified that another horse that had attended the show began experiencing symptoms potentially related to EHV-1 after returning to its home barn, while the horse with an elevated temperature had tested negative for the virus.

Wednesday, Feb. 23
West Palm Events announced the symptomatic horse from the day prior had to be euthanized. This was the first public account of what has made this outbreak stand out from the rest: an absence of warning signs until the horse was experiencing severe neurological symptoms.

“This horse exhibited no symptoms until late yesterday afternoon when it became neurological and experienced such severe symptoms that it was euthanized,” West Palms wrote. “Lab results will take a couple days for conclusive answers on what happened.”

In the same announcement, they said that overnight they were also made aware of a fourth horse at the show that had been at Desert International Horse Park inside the seven-day minimum.

Thursday, Feb. 24
The day after hearing word about the euthanized horse, there was an appropriate amount of concern from other boarders at our facility who were not in our program, and John and I decided to share a few of the many proactive measures we were taking in our program on social media. We hoped this would help educate the community about what was going on and perhaps encourage other trainers, owners and facilities to take extra precautions and be transparent so everyone could be armed with current information.

This paid off quickly, as I received text messages from friends at a nearby stable (not on the same property as us) that they had symptomatic horses, including one that seemed to have the same symptoms as the horse euthanized who had been at LAEC—no symptoms, no warning, not even a fever, until a rapid onset of severe neurological symptoms called for the horse to be promptly euthanized.


Friday, Feb. 25
Our horses received an immune booster injection at the direction of our veterinarians. Additionally, facility management announced that horses were prohibited from entering or leaving the property out of an abundance of caution. At this point, there were still no confirmed cases in the Orange County area.

Sunday, Feb. 27
One week into our show horses being quarantined, we decided alongside our veterinarians to extend their quarantine from seven days to 12, out of an abundance of caution. We were also made aware of two other cohorts of horses with other trainers that had left the facility and returned on Sunday, Feb. 20, the same day our show horses returned from LAEC.

Monday, Feb. 28
We found our first symptomatic horse. During morning temperature checks, John found one of our elderly horses (who had not left the property in five years, but who was stabled in the same row as two of the quarantined horses who attended the LA show) acting out of character. The gelding, EZ2CY, initially displayed what looked like mild colic symptoms but no fever. He seemed to be uncomfortable and was laying down for an extended period of time.

Once vets arrived and everyone got him back on his feet, he seemed to have some weakness in his hind end, which we were told could have just fallen asleep from laying down for so long. Our vets decided to test him for EHV-1, just to be sure what we were dealing with. Additionally, we asked all of our clients to stay home from the barn so we could control all biosecurity measures and reduce foot traffic at the barn.

EHV Diary Kai & Dax Mary

EZ2CY, the horse who contracted EHM, schooling at homes several years ago with owner Mary Edwards, who purchased him as a 4-year-old.

John stayed the night with that horse at the barn every night from there on. He talked to him, played him music and reminisced about the 17 wonderful years they had together. Our careers seemed to be punctuated by memories of this wonderful horse, the first horse I “coursed big” on when I was 14 years old. He never put a foot wrong for his owner in all the years she had him, from when he was 4 years old.

Monday, March 1
A different trainer at our facility found one of their horses showing severe neurological symptoms. What also initially seemed to be signs of colic quickly evolved into a tragic situation where the horse was unable to get up and had to be euthanized promptly. At that point, we still had no confirmed cases of EHV-1 or EHM on the property, but there seemed to be a tacit understanding among all who had witnessed the neurological horses: The virus was here and had slipped past all our defenses.

This same day, we had another horse in our program, who also had not left the property in over a year but had been stabled in the vicinity of two show horses, come up with a mild fever. Our vets promptly tested the gelding for EHV-1, and we moved all the horses in our program to a full lockdown, with no horses allowed out of their stalls.

Wednesday, March 2
I think we all started to see the writing on the wall. I received texts from friends at a different Orange County facility that they had lost another horse, the same way as the one prior: no symptoms until it was severely neurological and had to be euthanized.

As the president of the San Juan Equestrian Coalition, John started pressing for horses to not be allowed in any upcoming local parades, including the Laguna Beach Patriot’s Day Parade and the Swallow’s Day Parade, one of the largest equine parades in the country. John was successful in this pursuit, and his quick thinking gave organizers of the Swallow’s Day Parade enough time to advertise it as an event without horses, to show the equine community support during this time.

Thursday, March 3
Our horse with neurological symptoms, EZ2CY, was confirmed positive for equine herpesvirus myeloencephalopathy secondary to equine herpesvirus-1 (EHV-1 non-neuropathogenic strain). At this time, he had lost his ability to urinate on his own, and due to diminished quality of life, we made the heartbreaking decision to euthanize him late that night. The test results of the other neurological horse at our facility (but not in our program) had come back with the same findings—three days after the horse had been euthanized. Results for the horse in our program that previously had an elevated temperature also came back as positive for EHV-1.

EHV diary Kai

EZ2CY, with owner Mary Edwards, was a dearly loved barn favorite at John Berney Equestrian for 17 years.

I continued to email clients updates, and post on social media, even through what had been the most devastating loss in our program. While it was the hardest thing I’ve had to write, we figured if our transparency could warn people or save just one horse, then our loss wouldn’t be for nothing.

Cognitive Dissonance Online
Through the sleepless days and nights for John, his family, our assistant trainer and myself since our first horse got sick, we’ve spent every moment possible at the barn, checking horses, disinfecting and waiting for results.

In the meantime, several California horse show management groups continued to send marketing emails and post on social media about their upcoming shows, encouraging trainers to get entries in.

Many California riders posted on social media, encouraging people to “stop moving horses, otherwise we might lose the rest of the show season,” as if that was any sort of priority in comparison to the horses that were being lost every few days. In the midst of our suffering, it was abundantly clear who cared about the horses and who cared about horse shows.


Through all of this, I continued to post on John Berney Equestrian’s social media and send daily email updates to all of our clients, some days this consisted of three or four emails because of how quickly the situation was changing. From before our horses returned from LAEC, I had been sending out the strictest biosecurity protocols to our clients. We were armed with disinfectant at every stall, no shared tack, no foot traffic across the property, every measure suggested by the state, and so much more.

We do not know where our horses picked up this virus. No other horses from the barn where the horse who previously showed at LAEC was euthanized ever got sick, and CDFA, which released that barn from quarantine March 9, has said it has not found a definitive epidemiological link between that case or that show and the cases at Desert International Horse Park. We do know that, while we quarantined our show horses to the best our abilities and kept them as far apart from other horses as our facility set-up would allow, both of our horses who contracted the virus were stabled in somewhat close proximity to them.

This is the story written between delayed updates on the CDFA website. The one written on the tired faces of trainers and staff who have spent late nights doing all they can here for the horses. Let our experience be enough to take every possible precaution to protect your horses, even if the virus is not in your area.

What We’ve Learned

This is not the first EHV-1 outbreak we have been through. We’ve had several over the years at neighboring properties, and after lockdowns, a few sick horses and lots of biosecurity measures, things returned to normal. We were privileged to attend talks from the state veterinarian during those times about daily biosecurity practices we could implement to keep our horses safe, even in the absence of an outbreak. Those practices are reflected everywhere you look in our program, with practices put in place long before the current outbreak: If you walk into our tack room, you will see an obsessively labeled wall of bridles, martingales and other tack, each piece, with a horse’s name on it. Everything gets put back cleaned and wrapped so our horses don’t have to share equipment.

During this outbreak, we had taken every precaution imaginable, but we’ve learned this strain doesn’t seem to be like ones we’ve seen in the past, where a fever is a clear indication of infection, and horses would slowly deteriorate over time if they were positive for EHM. The onset of neurological symptoms in this outbreak seems more rapid in horses who test positive for EHM. While taking temperatures is still critically important in this fight, the absence of a fever does not mean a horse doesn’t have the virus. We continue to take temperatures morning and night, but beyond that, we take note of the behavior of all our horses.

We are deeply grateful for the many proactive measures management at our facility took early on, especially enacting lockdowns of the property and horses before it was required by the state. This is the type of proactive management we hope other stables can follow if they find themselves threatened by the virus.

Through this outbreak, all of us at John Berney Equestrian have learned the power and value of transparency, even in the face of devastating loss. Being forthcoming about our experience has helped other trainers make decisions in the time between our social media posts and the CDFA releasing information.

As of March 9, with the Los Angeles County barn and another in Ventura County released from quarantine, eight counties in California are fighting this EHV-1 outbreak.

A Word For California Show Managers

Please understand what a difficult time many California barns are going through. This is not a time to shout out your sponsors on social media, nor is it a time to talk about upgrades being made to horse show venues or encourage trainers to get entries in. This is a time to offer help, compassion and share critical information with others so they can protect their horses.

Please halt your regular marketing and try to connect those who need help with those who can offer it.

On Friday, March 4, our facility finally received donated portable stalls to construct an isolation area for horses that had tested positive, and a separate one for horses awaiting test results. We would like to thank the Ridland Group and Blenheim EquiSports for this kind donation of stalls. There are other facilities that may need this and will be grateful to know they have support from horse shows during this uncertain time.

Nina Thornton is a barn manager for John Berney Equestrian, a hunter/jumper program located in Orange County, California, at one of the facilities with confirmed cases of EHM and EHV-1. Responsible for communication with clients, owners, and social media, Nina and head trainer John Berney chose to share everything publicly—from their precautions after returning from a horse show at Los Angeles Equestrian Center, through the death of one of the horses in their program due to EHM.

Follow John Berney Equestrian’s updates through this EHV-1 outbreak on Facebook and Instagram.



Follow us on


Copyright © 2024 The Chronicle of the Horse