Horse Health: The Virus Almost Every Horse Already Carries — What to Know Before the Next Outbreak with Dr. Bruno Karam

9 Jun 2026 · 55 min · S2 E25

Episode Horse Health: The Virus Almost Every Horse Already Carries — What to Know Before the Next Outbreak with Dr. Bruno Karam

0:00 55:17

Right now, somewhere in the horse world, a horse is shedding a virus it's carried since it was a foal. Its owner doesn't know. The horse looks fine.

That's EHV-1. Equine herpesvirus. And Dr. Bruno Karam, equine internal medicine specialist, wants you to understand it before the next outbreak — not during it.

We recorded this conversation in the wake of last year's EHV-1 cluster at the National Finals Rodeo. Horses stumbling. Famous horses hospitalized. People asking whether the event should have run at all. And a lot of horse owners left with unanswered questions about a virus they'd heard about but didn't fully understand.

This episode answers those questions.

EHV-1 isn't new. The neurological form — EHM — isn't new either. What's changed is the density of horse movement. Western circuits don't park in one city for two weeks. They move. And they move on timelines shorter than the incubation period. By the time a horse shows symptoms, it's already three states away from where it got infected.

Bruno breaks down how the virus behaves in the body — biphasic fevers, white blood cell hitchhiking, the vasculitis cascade that leads to spinal cord involvement. He explains why your vaccinated horse can still shed. Why a healthy horse with no symptoms can spread it. And why giving Banamine the moment your horse feels warm is the single most counterproductive thing you can do in an outbreak.

The practical guidance in here is specific. Take temperatures twice a day. Know what's normal for your horse before you need to know what's abnormal. Don't share thermometers. And if your horse is questionable at a show — be okay with not showing.

He also talks about something that doesn't get said enough: we don't yet have data on why some horses get sick and others don't. We're still retroactively analyzing the outbreaks. The science is moving, and what we do today may not be what we do in ten years. That's not a reason to panic. It's a reason to pay attention.

Dr. Bruno Karam is an equine internal medicine specialist. He trained at Texas A&M under Dr. Michelle Coleman and has worked some of the most complex infectious disease cases in the field. He ended up on the news last year because of EHV-1. He came on this podcast to give you the version of the conversation that the news couldn't.

If your barn shares thermometers, send this to your barn manager.

Subscribe to the NOËLLE FLOYD Podcast — formerly Dear Horse World — wherever you listen.

IN THIS EPISODE YOU WILL LEARN

• Why nearly every horse already carries EHV-1 latently — and what triggers shedding with no visible symptoms • The exact biological pathway from respiratory infection to spinal cord damage that causes EHM • Why the western show circuit's travel structure created exponential exposure chains in 2025 • What the EHV vaccine actually does and doesn't do, and why it still matters for herd immunity • How to take and interpret your horse's temperature using their individual baseline, not just 101.5°F • Why giving Banamine at the first elevated temp can mask early outbreak warning signs • The most overlooked transmission vector at shows: human hands moving between horses

To find out more about Dr. Bruno Karam DVM - Pilchuck Veterinary Hospital - Equine

This episode is sponsored by Pegasus Training & Rehabilitation Center

Here at Pegasus, our mission is to run a first class horse training, rehabilitation, and conditioning facility; provide horses of all disciplines with full and complete care of the highest quality; partner with our clients to ensure that we not only meet, but exceed, their individual goals and needs; and maintain our facility and equipment with the highest level of care.

To find out more about Pegasus - website | instagram | facebook

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