Perhaps never has modern society at large been focused on controlling infectious disease as much as it is now; masking, social distancing, hand-washing, and surface disinfection have become regular practices to prevent COVID-19 transmission. But, pandemic or not, equine hospitals must always prioritize biosecurity, defined as everything they do to keep disease-causing viruses, bacteria, fungi, parasites, and other microbes away from animals, people, and the environment. This is because of the nature of equine veterinary practice: Horses can carry pathogens, whether they show clinical signs or not, and some hospital patients, whether due to illness, surgery, or travel stress, might be immunocompromised and, therefore, especially vulnerable to infection.

Lucas Pantaleon, DVM, MS, Dipl. ACVIM, MBA, an internal medicine specialist, founder of DVM One Health, and an advisor for Ogena Solutions, a biosecurity company; and Heather E. Lewis, AIA, NCARB, AAA, a partner and principal at Animal Arts Design Studios Inc., an architecture firm in Boulder, Colorado, that designs animal care facilities, described the importance of facility design for infection prevention at the 2020 AAEP Virtual Convention.

Pantaleon started by sharing an elaborate diagram illustrating the myriad ways health and disease arise and interact in humans and animals. “Therefore, in order to solve problems related to health and disease we need to think about concepts that call for a multidisciplinary collaboration,” he said, something the “one health” concept does by bringing together people from multiple disciplines—in this case, an equine internal medicine specialist and an architect—to work collaboratively to maintain the health of people, animals, and their environments.

Yes, You’re a Fomite

If you think about an equine hospital, what moves around the facility the most? By far, it’s the people. Pathogens can travel between surfaces and horses on hands, shoes, clothing, and items we carry. “Humans are very good fomites,” or objects or materials likely to carry infectious pathogens, Pantaleon said. “Therefore, hand-washing is a key aspect of what we do, not only when we touch horses, but it’s another tool in the toolbox to prevent human-to-human diseases, something we are much more aware of since the pandemic.”

The other ways colonized (pathogens are present but the patient is not showing clinical signs) or infected (horse is showing clinical signs of disease) hosts spread pathogens in the environment are through the air and via the fecal-oral route. The former is influenza’s primary means for spreading, and the fecal-oral route permits bacteria such as Salmonella to disperse. Salmonella and other bacteria can cling together to make coatings called biofilms in the environment. These make them more resistant to environmental factors (heat, cold, moisture) and disinfectants and allow them to live in the environment for months to years, if the conditions are right, Pantaleon explained. Considering that veterinarians use antibiotics regularly in their patient populations, some of those bacteria found in a hospital could also develop resistance.

“As a veterinarian, when I think about infectious disease prevention in a hospital, I look at the hospital as my patient,” he said. Proper hospital design and correct cleaning, removal of biofilms, and disinfection practices make way for the healthiest patient.

“The process of cleaning and disinfection breaks the transmission cycle of the disease,” he said, “eliminates the source of the infectious agent, and also enhances the public image of the hospital and makes it a more comfortable environment, not only for our patients but for the animal care team and our clients.”

Pantaleon explained the different risk levels of veterinary patient populations: Healthy horses visiting on an outpatient basis pose minimal risk of disease transmission; short-term hospital residents such as healthy nurse mares and foals pose medium risk; and patients such as foals with Salmonella pose high risk. Each risk category requires a different level of building materials, which we’ll cover in a bit.

“We are in an equine hospital, where we always have bacteria and other pathogens,” he said. Because it isn’t a sterile environment, “we have to put in place (cleaning and disinfection) measures … and proper hospital design in order to try to shift that equilibrium toward health.”

Lewis, who works with veterinary hospital clients to both design and renovate spaces with biosecurity in mind, described ways to make that shift:

Sink Location/Design

“I’m very old-fashioned when it comes to hand hygiene because hand-washing itself is much better than hand sanitizers,” she said. “We’ve been using hand sanitizers this year (to protect against COVID-19 transmission), but they don’t remove soiling, and they’re not as effective when we’re dealing with non-envelope  viruses,” which aren’t encased by a lipid membrane, can be difficult to kill, and, as such, can live for a long time on surfaces.

Convenience is the key to promoting proper hand-washing practices in an equine veterinary hospital. Good spots for placing a scrub sink—which is deep, has a slanted front (shallow sinks splash), and has a touchless design—include outside the isolation stall and near the doorway of any high-risk area. It’s crucial that you don’t place the sink where you must touch a door handle after washing your hands.

Establish ‘Clean and Dirty’ Flow

This applies to both the overall hospital, with the flow of isolation versus healthy patients, and individual room design. It also includes the flow of equipment and other supplies.

“Laundry is actually ground zero for potential fomite transmission,” said Lewis. “This is often a dirty space with many dirty items in it, and we don’t think enough about laundry design.

“One tool that I love is the idea of different colored carts; we use red carts for dirty laundry and green carts for clean laundry,” she added. “This is very easy: red stop, green go.”

Hang Hoses High

Hoses are necessary for cleaning a space but, if they drag through dirty water on the floor, they can contaminate areas you’ve already cleaned. Lewis said the best way to deal with hoses is to get them off the floor: “I love to mount hoses high on the wall where they can completely dry between cleanings and where they are not as likely to drag across the floor surface.”

Dispense Disinfectant

Speaking of hoses, veterinary teams use them to apply disinfectant—something you can inject through the line or introduce through a dispenser attached to the hose end. “The injection through the line is wonderful because you can change the disinfectant level depending on risk,” said Lewis, “but many of our clients use the end-of-the-hose delivery because it’s less expensive, and it’s still quite effective.”

Select and Maintain Cleanable, Disinfectable Finishes

“Beyond this fomite transmission concept, which is so, so important, we can start thinking about how to prevent the fecal-oral route, and with this particular mode of transmission, the most important thing is to maintain and design the sanitary environment using good, cleanable, disinfectable finishes,” she said.

Operating rooms see a lot of fluids because of the nature of the surgeries and the water-heavy cleaning protocols. “We actually don’t do that in human health care or small animal health care, so this is a hard room to design,” said Lewis. “My favorite floor surface is a urethane floor, which is like an epoxy but more chemical-resistant. This floor comes across and goes up the wall and coves into the wall joint to create a completely sanitary joint to allow for effective cleaning, which prevents the growth of biofilms.”

Further, she said it’s important to use a sanitary material such as a block filler up the wall—to fill pores that can trap microbes—and cover with a cleanable high-performance coating.

Pick the Right Floor

Besides the surgery suites, any hard-working medical space in an equine hospital needs to be furnished with surfaces that can be readily cleaned and disinfected.

“When we think about floor surfaces that horses can walk upon, they need to be resilient, squishy so the horses don’t slip,” she said. “But I actually prefer surfaces that are totally sealed on the top, so they also maintain the ability to be cleaned. These are poured floors, such as urethane poured floors that are resilient and rubber poured floors that are resilient.”

Veterinarians and practice managers also need to be thinking about sanitation in the human-only areas of the hospital—particularly the drawbacks of carpet.

“Carpet weighs on average twice as much when you take it out as it did when you put it in,” she said. “Carpet is a great material for harboring all kinds of dust and dirt and potential pathogens. So even in the human areas we like sealed floor surfaces.”

Match Protocols to Risk, Materials

Above all, practice owners must be sure the protocols used for cleaning match with the patient risk and hospital material designs, said Lewis, building on Pantaleon’s risk categories. So, for instance, you wouldn’t want to select porous wood surfaces for a barn that will hold sick, high-risk patients and that will need to be hosed repeatedly. If you were to hose barn surfaces like this, you’d make it worse, creating an ideal environment for the growth of resistant biofilms.

Prevent Airborne Transmission of Pathogens

Take the current pandemic recommendations of social distancing and kick it up a few levels for equine isolation units. Consider keeping horses in isolation at least 60 feet away from healthy patients, said Lewis, and keep them fully separated from each other. This includes ensuring they have their own sets of tools and equipment, reducing fomite transmission.

“Most importantly,” she added, “we need direct exhaust from an isolation stall to the outside to prevent any cross-contamination. For example, through ductwork running from stall to stall.”

As for office spaces, treat them like office spaces when designing them—generally, it’s a bunch of healthy humans walking around. But medical spaces, with sick animals, require fully enclosed, conditioned spaces with enhanced air changes. Certain areas, including ICUs and isolation units, need 100% exhaust without recirculation. “We also use a tool called pressurization that means we put more air in a room (such as surgery) that we want to maintain cleanliness within, so no dirty air can flow into that space,” said Lewis.

Make It Cost-Effective

Working in indoor/outdoor environments is safer than indoor spaces, as we’ve learned with COVID-19, and it’s one of the best ways to create a cost-effective design. “Use the building mechanical system like a whole house fan to supplement the natural ventilation,” said Lewis, and include features such as office windows that can be opened.

“In summary, hospital design and infection control go hand in hand,” said Lewis. “And by creating a dialogue between professionals who focus on different aspects of animal health, we can create an environment that’s much safer, much better, much healthier, much cleaner, and a better place for you to work, and a better place for your horses.”