From Healthy to Hazard

The critical role of biosecurity in horse care.

Looks can be deceiving when it comes to whether a horse has been exposed to an infectious disease. Deceiving, and dangerous. “I’ve seen too many train wrecks where an owner brings a horse back from a show, it looks great when it arrives, but then six days later it is sick and blowing strangles all over everything,” said Kevin Hankins, DVM, MS, MBA, managing equine veterinarian at Zoetis.

While many horse owners focus on avoiding illness through good management at home, shows, or during travel, it’s equally important to be prepared for outbreaks. Indeed, a well-developed biosecurity plan is essential not only for preventing infectious diseases but also for ensuring there’s an effective response plan in place if prevention fails, so the disease doesn’t spread.

“Biosecurity encompasses not only prevention, but a response, because prevention is never 100% effective,” Dr. Hankins said. “What happens if infection still occurs? You’ve got to be able to respond.”

Main threats

The main biosecurity threats in horses center around three main respiratory diseases that can be spread in three very different ways.

The first, equine influenza, is highly contagious and easily spread through the air over long distances (300 feet or more), making it a major threat during outbreaks with rapid transmission among horses.

The second threat, equine herpesvirus (EHV), is spread through direct contact and affects the respiratory system.

The third, strangles, is spread primarily through oral transmission, often via contaminated water, and caused by the Streptococcus equi bacterium.

The variance of how horses can encounter these threats is what makes biosecurity so challenging. “With aerosolization, there is not much you can do because it’s going through the air,” said Dr. Hankins. “But with direct contact or oral transmission, you can manage prevention by not sharing tack, using your own water buckets, trying to clean up the stalls, etc.”

Where to start

Biosecurity at home involves coordination with veterinarians and includes both preventive techniques and response strategies to minimize the impact of disease.

“The very first step is to get your veterinarian involved,” Dr. Hankins said, “because if you do have a biosecurity event, you’re going to want to be in constant communication. So, start with that.”

The horse owner’s veterinarian can help make sure the horse has its core vaccinations and identify with their veterinarian what risk-based vaccinations may be needed, and how often. Core vaccinations are WNV, EEE, WEE, tetanus and rabies. Risk-based vaccinations often include equine influenza, herpes virus (rhino) and strangles.

Next is an evaluation of the facility. If the owner has a horse that gets sick, the gold standard would be to have a place to isolate it from the others. “You want to make sure you’re not scrambling around at the last minute trying to come up with disinfectants or foot baths, for example,” Dr. Hankins said. “You want to have a setup where either in your TAC room or someplace similar you’ve got a printed response or communication sheet that explains what you do at your facility to help prevent a biosecurity problem.”

Plans will vary depending on the location and intended use of the facility. “The plan is going to be different at a horse show than it will be at your farm, breeding facility, boarding facility, etc.,” he said. “It needs to be customized for what you’re going to be doing.”

Key transportation precautions

When transporting a horse, effective biosecurity requires careful planning, proper vaccination and strict control of exposure risks. Key precautions include:

• Plan ahead. Transport stresses horses and can suppress their immune systems, making them more vulnerable to disease. Plan your trip well in advance, considering every stage – from departure to return.
• Vaccinate properly. Ensure horses are vaccinated at least 4–6 weeks before travel to give their immune systems time to respond. Last-minute vaccinations won’t be effective in protecting them during the trip.
• Limit exposure. Minimize contact with other horses and shared items. Bring your own water buckets, feed and feed tubs, grooming tools and tack, and avoid switching feeds while traveling, as dietary changes add stress.
• Be “snobbish” about contact. Avoid unnecessary interactions with other horses and people. Discourage petting from strangers who may have touched other horses. Keep your horse’s space as private and isolated as possible.
• Evaluate the facility. Before arrival, horse owners should ask if the venue requires health certificates (preferably issued within 14 days), temperature monitoring and disease control protocols. Check whether they limit dog movement and restrict general public access – both are important disease control measures.
• Disinfect and clean. Owners should plan ahead and bring supplies to clean and disinfect their equipment regularly. Trailers should also be sanitized before and after transport.
• Have a contingency plan. Horse owners need to have already considered what they would do if there’s an outbreak at the event or if they are required to quarantine.

When infection occurs

Dr. Hankins believes a good rule of thumb for horses that have traveled to a show is to treat them as if they are sick when they return. “The minimum I would recommend is 14-day isolation, because the preincubation period for a lot of diseases, like strangles, is about 10 to 12 days,” he said.

Next, owners should take the temperature of the horse. “Most places say to temp once a day, but I recommend twice a day, because a lot of these diseases have biphasic fever, so they can be low one time and high the other,” Dr. Hankins said. Temping twice a day gives you a better chance of catching an infection early.”

Utilizing Serum amyloid A (SAA) testing is also beneficial for early detection. SAA is a major, acute-phase protein produced by the liver that is a reliable biomarker for inflammation due to infection. The SAA levels quickly and significantly increase in response to an infection. Veterinarians can detect and measure infection in 10 minutes using Stablelab, a hand-held diagnostic blood test that measures and quantifies SAA. SAA has been shown to be 30 times more sensitive than a thermometer in identifying subclinical infection, before your horse even starts showing signs, giving veterinarians a head start on treatment, Zoetis notes on its website.

Dr. Hankins understands that not every horse owner has the capability of maintaining a 14-day quarantine. “I know a lot of places can’t do it, and I understand that, so if you can’t totally isolate them, then try to do the other things; minimize contact with other people, temp them twice a day, feed and monitor their health.”

Owners will know their horse best and may be able to pick out signs of an infection just in a change in their habits. “Know what’s normal for your horse, because if you know what’s normal, you’ll be more able to tell abnormal.” Has the horse gone off feed? Are there any changes to urination? What about defecation, such as watery fecal? Is the horse breathing harder? Can you hear harsh lung sounds?

“Horse owners should know how to use a stethoscope,” he said. “They should be able to listen to their horse’s heart. The heart rate is going to increase when they’re sick.”

Veterinarians play a critical role in biosecurity – not only as medical experts but also as trusted advisors who design, implement and monitor biosecurity plans tailored to each facility’s unique risks. Horse owners shouldn’t be afraid to at least call their veterinarian if they suspect their horse has an infection of some kind. “A lot of horse owners are afraid to call up because they don’t know what’s going on, and they’re afraid they’re crying wolf,” Dr. Hankins said. “Veterinarians are much more receptive to knowing about something up front, rather than getting a call when it’s become serious.”

A valuable resource

The Equine Disease Communication Center (equinediseasecc.org) is a valuable resource for horse owners for several key reasons. It provides up-to-date alerts on infectious equine disease outbreaks across the United States and Canada. The data is submitted and confirmed by licensed veterinarians and state animal health officials, ensuring accuracy and credibility. The site features interactive outbreak maps that allow users to view current and past disease incidents geographically, making it easy to assess risk in specific regions. The website offers educational materials, including information on symptoms, prevention, and management of common equine diseases like EHV, strangles, and West Nile virus.

Photo credits:

istockphoto.com/Trish Calhoun

istockphoto.com/Jack N. Mohr

istockphoto.com/Anderson Coelho