Imagine a pristine equine hospital: The floors and walls are nonporous and easy to clean and disinfect. Antiseptic foot baths and surgical booties lie before the intensive care unit door. And veterinarians and technicians scrub their hands in pedal-operated stainless steel sinks between cases. In a perfect world, barriers such as these prevent disease-causing microbes (think equine herpesvirus or influenza) from spreading between horses.

But most of our horses don’t live in a perfect world, and most veterinary appointments take place in barns, not surgical suites. So, considering the environment and limitations for biosecurity, how can veterinarians and equine managers prevent disease spread between horses, especially during outbreaks?

To answer that question and find workable solutions, veterinarians and state animal health officials gathered for a table topic titled “Practical Biosecurity” at the 2016 American Association of Equine Practitioners Convention, which took place Dec. 3-7, in Orlando, Florida. Scott Weese, DVM, DVSc, Dipl. ACVIM, of the University of Guelph, in Ontario, Canada; and Tracy Norman, VMD, Dipl. ACVIM, of Blue Ridge Equine Clinic, in Virginia, moderated the interactive discussion, which covered a variety of equine-related biosecurity issues. Two specific topics included horse farm and ambulatory practitioner biosecurity.

“The term biosecurity is really a misnomer when it comes to horses,” Weese said to the group as the session opened, and Norman nodded her head in agreement.

“Infection prevention protocol is a more realistic term,” she said.

Horse Farm Biosecurity

Farm managers, especially on breeding farms that also house transient horses (e.g., show horses, breeding animals that leave the property), should implement basic measures to prevent disease spread and mass losses of pregnancies and young stock. Audience member Josie Traub-Dargatz, DVM, Dipl. ACVIM, of Colorado State University, suggested keeping horses in “cohorts” (groups sharing distinct similarities) to reduce disease exposure risk. For example, on racing farms, yearlings should live separately from horses actively moving back and forth from racetracks or training facilities.

Furthermore, Traub-Dargatz pointed out tack and equipment can serve as fomites (inanimate objects that can pass disease) and spread disease. As a solution, she recommended color-coding equipment and assigning individual colors to each cohort. For example, red rakes, buckets, halters, lead ropes, bucket brushes, etc., for the yearlings and all blue equipment for the racehorses. “Don’t cross the two,” she said.

When cleaning barns, the moderators cautioned against using pressure washers. High-pressure water might seem efficient and aggressive for cleaning, but this is only at a macro level, and it doesn’t kill disease-causing agents. In fact, pressure washing can spread microbes by aerosolizing them and create a wet, more hospitable environment for them. “High pressure drives infection agents into nooks and crannies,” Norman said.

Weese added that smooth surfaces free of organic materials (e.g., manure, dust) are easiest to clean. “Pressure washers can break down surfaces, making them harder to disinfect in the future,” he said.

Disease Prevention for Ambulatory Veterinarians

Ambulatory practitioners pose specific risks for disease spread. By the nature of operating out of a vehicle and moving directly from one appointment to the next, ambulatory practitioners are at risk for spreading the diseases they’re trying to treat and prevent. Specifically, it’s difficult for an ambulatory veterinarian to disinfect his or her hands between farm calls.

“Ambulatory vets should disinfect their vehicle steering wheel often,” Norman said. “It can harbor pathogens and contaminate hands (after the vet has washed his or her hands).”

Audience members also offered solutions for their professional peers:

  • Use administrative controls, such as scheduling all patients with fevers (a possible indication of infectious disease) as your last patients of the day;
  • If you rely on alcohol-based hand sanitizer for hand hygiene between farm calls or patients, make sure to let it dry thoroughly after application and before putting gloves on your hands;
  • Set up your house so that you enter and can strip off work clothes, put them in the washer, and shower immediately before seeing your own horses. “Studies have shown washing laundry with hot water isn’t great for killing pathogens,” Weese said. A hot dryer is, however, he added.

Take-Home Message

Biosecurity on horse farms and for equine veterinarians, especially in ambulatory practices, presents challenges and is imperfect. Farm managers and veterinarians should focus on practical, doable measures and routines to reduce infection spread.