The Modern Equine Vet
May 2024
Vol 14 Issue 5 2024
Click Here to View Table of Contents

Ask the Infectious Disease Expert

How can I reinforce the importance of rabies vaccination among clients?

Bryant Craig, DVM

When people ask me about the need for rabies vaccination, I’m transported back to when I was 8 or 9 years old. My pony, Dolly, wasn’t acting herself, so the veterinarian came to check her.

The next day, Dolly passed away. The vet tested her body for rabies and found she’d been positive.

We’d all handled Dolly the day before, which meant we’d been exposed to rabies. Everyone had to get immune globulin shots to try to prevent infection. Luckily, the shots worked and none of us became ill.

This experience shaped the message I’ve shared with clients throughout my career in practice: 100% fatal. Always preventable.

As veterinarians we understand the critical importance of the rabies vaccine, but our clients are often conflicted by diseases that aren’t seen with much frequency. Yet each year cases are reported. So far in 2024, at least two cases of equine rabies have been confirmed, one in Tennessee and one in Georgia.1

There’s always the significant and serious potential for any infected animal to transmit the disease to humans, which carries important public health consequences. That’s why the American Association of Equine Practitioners (AAEP) recommends every horse be vaccinated every year.2

With wildlife activity increasing with warmer weather, the threat of rabies is rising also. Now’s the perfect time to remind owners of the need to keep their horses current on rabies vaccination. Horses are curious creatures, and a nip on the muzzle or limb could be disastrous. Many exposures go unnoticed, making vaccination not just a precaution but a necessity. Since wildlife may enter barns (especially at night), both stalled horses and horses on pasture have the potential to be exposed.

A definitive protective titer has not been established against the rabies virus; however, research indicates that a rabies virus neutralizing antibody (RVNA) titer value ≥0.5 IU/ml is evidence of an immune response to the vaccine in the horse. Owners of horses with previous serious adverse reactions to the rabies vaccine should consult with their veterinarian on future vaccinations.

The reality is many factors contribute to immune response. When it comes to rabies, veterinarians are cautioned to carefully weigh with clients the risks vs. benefits of serologic testing. Rabies vaccination is known to be a reliable protective measure in horses. Therefore, failing to vaccinate increases the risk of a fatal outcome. More information is available through the AAEP Serology Guidelines.

Even if rabies hasn’t been in the news in your area, it does still occur and horses may be exposed without owners knowing it. If they are, the outcome is likely fatal. That’s a risky proposition when vaccination provides such an easy, economical solution.


Bryant Craig, DVM, is associate director of scientific affairs for equine professional services and pharmacovigilance at Merck Animal Health. Prior to joining Merck Animal Health, Dr. Craig owned and operated a private equine veterinary practice for six years in central Oklahoma before joining a top Quarter Horse ranch as resident veterinarian.


Provide your clients with more information with this Rabies Quick Facts guide from Merck Animal Health.

1. Equine Disease Communication Center (
2. AAEP Vaccination Guidelines (

Copyright © 2024 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All rights reserved.