- Oct 2, 2001
There are few things sadder than a horse not in contact with other horses. A herd animal by nature, the horse always feels safest and most content when in company of others of his kind; isolation doesn’t come naturally to him. But in certain situations, isolation might be just what the doctor ordered—both to preserve his own health, and to protect the health of the equines around him.
Strict quarantine, in which a horse is completely separated from contact with other horses, is a smart strategy for limiting the transmission of disease. There are several scenarios in which quarantine is a good idea, ranging from the isolation of an already sick horse from his apparently healthy herdmates, to the "better safe than sorry" separation of any new arrival from an established herd, to the government-regulated quarantine of a horse imported from another part of the world to prevent the introduction of non-indigenous diseases. In all of these situations, quarantine can be very effective, providing it’s done right.
Art King, DVM, is a Fort Erie, Ontario-based equine veterinarian who has traveled extensively with Canada’s endurance team as it has trekked to competitions world-wide. He notes that there are several levels of quarantine.
"There are different kinds of bio-security, depending on what you’re trying to control," he says. "The type of quarantine you’d institute for a respiratory infection is different from the quarantine for a disease carried by flying insects. Some diseases are transmitted through the air, others only by direct contact, and still others by vectors (such as insects) or fomites (objects, such as buckets, brushes, blankets, items of human clothing, or human hands or feet). The basic principle is to isolate one horse from exposure to other horses, but the degree to which you do that will vary depending on the situation."
There are two main reasons to put a horse in quarantine: to keep sick horses from infecting the healthy ones, or to ensure that apparently healthy animals aren’t carrying, or incubating, an infection that could spread into a healthy population. At its simplest (and least effective) level, quarantine simply might mean putting at least one empty stall between the isolated horse and the rest of the horses on the property. Ideally, a horse in solitary confinement should be housed in a completely separate building.
If you’re bringing a new horse onto your property, one which apparently is healthy, 30 days of physical separation from the rest of your equines should be sufficient to tell you if he is incubating any kind of disease. This timeframe, King says, also gives you time to get results back from tests your veterinarian might recommend. For example, if you don’t have a deworming record for the new horse, you might want to run a fecal check to test for worm populations before you turn the horse out with your herd. Or if the horse comes without a valid negative Coggins test (the blood test for equine infectious anemia), you’ll want to ensure he’s negative for the antibodies to the virus before you allow him to have contact with your certified-negative animals.
If, on the other hand, you’re isolating a horse which already is sick, there are several factors you’ll want to consider. First, ask yourself (or ask your veterinarian) how the infectious agent your horse has contracted is transmitted. Is it spread through the air, as are many respiratory diseases? If so, over what distance? (Viruses tend to spread more easily over large distances; bacteria, such as the organism which causes strangles, are comparatively larger and heavier and tend not to spread more than a few feet through the air.) Is the disease spread by contact, like ringworm? Can it survive on buckets or brushes, the walls of your horse trailer, or your shoes? Do you have to worry about where you put your manure pile, or where fluids such as urine from the infected horse are draining? If it’s spread by insects, which insects are the culprits, and approximately how far can they travel?
The normal range of an insect vector is a surprisingly quantifiable thing; there is good data available on most species that tend to hang around horses, and the information is important to the design of a quarantine situation. Equine infectious anemia (EIA), for example, is transmitted by large biting flies such as deerflies and horseflies, which have a maximum range of about 200 yards. This knowledge has given us a good understanding of how best to prevent the spread of EIA; a horse with a positive Coggins test (indicating the presence of antibodies to EIA) will be highly unlikely to transmit the disease as long as he is kept at a distance of over 200 yards from other horses.
Sometimes other factors are at work as well. In the case of the various strains of equine encephalitis (Western, Eastern, and Venezuelan), mosquitoes tend to carry the virus common to their region, and they tend to bite horses, but they are only "competent" to transmit the virus when all the conditions are right. Time of year, temperature, and humidity have a lot to do with this—which helps explain why encephalitis outbreaks occur in some years and not in others.
Of course, many diseases are spread in more than one way. Vesicular stomatitis, for example, is thought to be spread both by insect vectors and casual contact. Although not particularly dangerous to horses, it’s generally considered as highly infectious.
All that’s needed to move a horse between the Canada/United States border is a current negative Coggins test, and a general air of good health. However, if you’re importing or exporting a horse to or from any other country, then some period of quarantine almost certainly will be required. (In some cases, a horse might be refused entry altogether.) The reason for import/export quarantines is that many equine diseases are particular to one part of the world, and most countries prefer to keep non-indigenous diseases out.
The world is divided up into "risk groups" when it comes to disease, says King. "The quarantine routine will vary, depending on where the horse is coming from. And the regulations are constantly changing as some diseases are eradicated, and others break out."
For example, horses being imported from most parts of Europe must conform to USDA regulations by entering the United States through one of three ports of entry: at New York City, Los Angeles, or Miami. There, horses must spend at least 72 hours in quarantine (However, some performance horses like "three-day horses" are in import quarantine for about 24 hours), during which time they will be tested for EIA, piroplasmosis (a protozoal blood disease common in Europe), dourine (a contagious venereal disease), and glanders (a bacterial disease, fortunately rare). Thereafter, (providing all the tests are negative and the horses appear healthy), geldings, and any horses younger than two years, are released, but mares and stallions of breeding age are subjected to a further period of quarantine to test for a sexually transmitted bacterial disease called contagious equine metritis (CEM; see The Horse of March 1998).
At a state-approved CEM quarantine facility, based either at a university such as the University of California, Davis, or at a licensed private farm, mares spend at least 15 more days in quarantine, undergoing three sets of tests for CEM. If all the results are negative, the mares are released. Because stallions are asymptomatic for CEM (that is, they can harbor the disease without showing any clinical signs), the only way to determine whether a stallion is infected is to have him breed mares, then test those mares. Two breedings are required for USDA CEM testing, and the ensuing culturing and testing can take up to a month.
For importers of big-ticket horses, all this hassle might well be worth it. Some licensed quarantine farms are, in fact, quite luxurious, offering separate riding and training facilities to allow recently imported horses to continue their work routines while waiting for test results to come through. The cost, however, can be high and should be factored into your budget if you’re considering horse-shopping across the ocean.
In situations where horses are being shipped internationally for competition purposes, then returning to their home country, quarantine regulations often are streamlined for the convenience of the competitors and officials. At the recent World Championship endurance race in Dubai, United Arab Emirates, for example, horses from North America were housed in one barn, and those from Europe, Africa, and Australasia all had separate facilities, thus effectively maintaining quarantine conditions right up until the day of the competition. Riders, veterinarians, and crew members involved with the horses were issued color-coded tags, which allowed them entry only to their own barns. For the return to North America, Dubai was able to certify that the endurance horses had not been exposed to any foreign pathogens, making the competitors’ quarantine on home soil brief and uneventful. A similar setup was employed for the 1996 Atlanta Olympics—horses which tested positive for piroplasmosis (a not-uncommon occurrence in Europe, where the disease is endemic and many horses asymptomatic) were housed in a separate barn, rather than being banned from competition.
Quarantine Is Forever With EIA
We tend to think of quarantine as a temporary situation, but that’s not always the case. Take equine infectious anemia, for example. EIA is currently considered incurable, and because it can be carried by horses who rarely, if ever, exhibit symptoms, it’s also virtually impossible to eradicate. The only way to control its spread is ruthlessly to euthanize, or quarantine, horses which test positive for the disease.
Regulations vary from state to state, but in those states which allow quarantine as an option, the arrangements require that EIA-positive horses remain at least 200 yards from all untested or EIA-negative horses for the rest of their lives. That means no showing, trail riding, or shipping for any reason. For many owners of apparently healthy, positive-Coggins horses, it’s preferable to the alternative. Furthermore, there’s no regulation against housing EIA-positive horses together, so it’s possible to provide some equine companionship by creating an EIA herd (such as are maintained at some American universities for study purposes).
Because EIA is transmitted by deerflies and horseflies, there are no particular risk factors for humans handling EIA-positive horses, so quarantine for them is relatively uncomplicated. Insect control obviously is an important factor, but handlers don’t need to bolt for the shower every time they touch an affected horse.
The Quarantine Routine
When you’re setting up a quarantine facility, whether it’s one stall or many, put some thought into how you’ll best limit the spread of infection. Here are some simple strategies suggested by King:
- Limit the air exchange between quarantined horses and the general population- ideally by placing the isolation stalls in a separate building. If you can’t do that, then locate the quarantine stalls at one end of the barn, near the exhaust fans, not near the air intake vents.
- Quarantine stalls should have a separate entrance. For instance, if the rest of your stalls open to a central barn aisle, you could place the quarantine stalls so that their doors open to the outside of the barn.
- Limit the movement of insects by screening doors and windows and using insecticidal sprays and traps as effectively as possible.
- Equip the quarantine facility with separate feeding, mucking, and grooming equipment, so that nothing is shared between the horses in isolation and those not in quarantine.
- Construct the stalls so that they are easy to disinfect. Wood is porous and difficult to clean; consider concrete block instead, or paint your wood with a waterproof, peel-proof paint sealant.
- Have a small "lip" on the floor of your stall, at the door, to prevent water and fluids such as urine from flowing in or out.
- Since some infectious organisms are soil-borne, keep a separate set of footwear in the quarantine facility, which you wear only there, or equip the facility with a foot-bath.
- Locate your quarantine barn downwind of your main barn, so that air-borne pathogens tend to blow away from rather than into the faces of your healthy horses.
- Handle your other horses before you deal with the ones in quarantine, and once you’ve handled them, don’t go back to the non-quarantine barn until you’ve washed all your exposed skin surfaces and changed your clothes. Even better, limit traffic to and from the quarantine facility by appointing a separate handler for your quarantined horses—someone who only deals with those horses and never mixes with the general population.
In the case of a disease that can be spread on surfaces, such as strangles, scrupulous use of disinfectants is a must. The strangles bacterium is tenacious, to say the least. It can survive for weeks or months on surfaces such as stall walls, buckets, and the interior of your horse trailer. Even if your horses are healthy, it’s a good idea to give your trailer a periodic power-wash, inside and out, and scrub it thoroughly with a disinfectant preparation (ask your veterinarian for suggestions as to which chemicals to use; some are better at killing certain types of organisms than others).
"If you follow all of these precautions," King says, "you should be pretty secure."
More stringent quarantine situations, such as might be needed to protect an immunologically vulnerable horse recovering from a delicate surgery or severe illness, are best handled by university or private veterinary hospitals. Set-ups there can resemble something out of the Center for Disease Control’s wildest fantasies, with glassed-in stalls, anti-contamination suits, and high-security airlocks to prevent the movement of air from one stall to another.
Dealing With Solitary Confinement
Being isolated from other horses is, in many ways, an equine’s nightmare. The feeling of separation from the herd, and from the daily activity of the barn, is a major cause of frustration in confined horses. Therefore, in addition to the hassles of quarantine, you also might have to deal with a very cranky horse. Minimizing the amount of stress he experiences while he’s confined can play a pivotal role in his recovery, or (in the case of a horse being quarantined "just in case") in your sanity!
Occasionally, horses will drop weight while in quarantine, either because they are fretting about their isolation or because illness, pain, or the medication they are being given makes them lose interest in food. For most confined horses, the first step is to cut back, or eliminate entirely, the grain portion of the diet, and substitute lots and lots of fiber. Providing your horse has an appetite, he can be offered hay free-choice throughout the day. If he’s too weak to cope with hay, try soaked beet pulp, laced with a little molasses, or hay cubes soaked in water to make them easier to chew. Work with your veterinarian to design a diet appropriate for your horse’s condition. If he or she gives the thumbs-up, you also can try tempting your horse’s enthusiasm with carrots or apples.
For the horse which really is moping, consider introducing an other-species babysitter, such as a goat. Misery loves company, but be sure that your babysitter critter isn’t vulnerable to whatever infectious condition your quarantined horse has.
What about the horse which continues to fret, despite your best efforts?
Some people find that providing a toy is the answer, and there now are as many horse toys on the market as there are Fisher-Price mobiles and playcenters for your infant’s crib. The old bleach bottle or fabric softener bottle suspended from the stall ceiling is a perennial favorite. Ask your tack shop if you want to explore more elaborate options. There are toys that roll and spin, toys with apple flavoring, and toys your horse can fling at his owner (be prepared to duck!).
Quarantine is far from an ideal situation for either handler or horse, but dealt with intelligently, it can be bearable. More importantly, it can be extremely effective in preventing the spread of disease, and that can save you a lot of time, money, and heartache in the long run.
About the Author
Karen Briggs is the author of six books, including the recently updated Understanding Equine Nutrition as well as Understanding The Pony, both published by Eclipse Press. She's written a few thousand articles on subjects ranging from guttural pouch infections to how to compost your manure. She is also a Canadian certified riding coach, an equine nutritionist, and works in media relations for the harness racing industry. She lives with her band of off-the-track Thoroughbreds on a farm near Guelph, Ontario, and dabbles in eventing.