Whether your horse is kept at your home or at a boarding stable, sooner or later you may be confronted with a disease outbreak. If you or your neighbor's horses go to organized trail rides, rodeos or horse shows, there is potential to bring back more than ribbons and good horse stories. Even if your horse is well vaccinated there is no guarantee that he won't become infected. When animals go to shows many are put under stressful conditions which they are not accustomed and they are often worked harder than they usually do. This may bring their immunity down and allow viruses and bacteria that the horse usually is not exposed to invade. The stressed body is then not able to shake it off as normal and sickness occurs. The influenza and strangles vaccine are only approximately 70 to 80% effective at preventing disease; however, they are great at reducing the severity of disease should your horse become infected. Symptoms of infection can begin as simple as your horse not being as active or not finishing his food or having nasal drainage. The first place to begin in your evaluation is his temperature. The normal temperature for a horse can range from 98.5 to 101.5 F. If your horse has been lying out in the sun, you may want to bring him to the shade or stall for an hour before checking the temperature. Take note of how rapid your horse is breathing and look for nasal discharge. If the temperature is elevated call your veterinarian for a consult. If the temperature is over 103 F, then you may need to consider it more of an emergency situation and get your veterinarian out quickly especially if he is not drinking enough water. Some horses can be very sick and will still eat so don't let that fool you. In the mean time, keep your horse in his stall and away from contact with others. You may move him to an area away from all other horses if this is available and you do not mind contaminating this area; however, nearby horses may already be exposed and it may be too late. If you must get your horse out, hand graze in an area where no other horses will be permitted and preferably in a sunny area where the sun can destroy any contamination that your horse leaves behind. Check temperatures on all horses on the property twice daily starting with the non sick horses first. Be a good neighbor and let your neighbors know if you have horses that become sick that may have come into contact with theirs over the fence.
During a disease outbreak, allow no one to move from horse to horse, either petting or giving treats or even cleaning stalls. Post a large sign to inform others that this particular horse is sick and not to be touched or turned out. Also, do not allow other horses to be tied near the stall or wander unattended down the barn area. Feed, water and clean stalls on the non sick horses first, then go to the sick horses. Use separate tools and brushes and halters for the sick horses then disinfect them. Also, change clothing after handling infected horses so as not to spread infection if you go to another horse. Spray bottles with disinfectants, hand sanitizers and foot baths with disinfectants outside the stalls are all helpful in trying to prevent spread of the infection. Do not spread their manure out in common pastures. Use ply board or plastic if necessary between stalls to prevent nose rubbing and aerosol contamination. Unfortunately, in the beginning of an outbreak it is difficult to know how many horses are already infected when the first horse becomes sick. Incubation periods can be from one week to two weeks or more.
As the events unfold, I recommend weekly draining, cleaning and disinfecting of all water troughs as they tend to harbor infectious organisms. Disinfect all stall cleaning utensils daily. Never put the water hose into the stall water buckets to fill then as they can spread problems. Let the water flow in from above the bucket or place the water hose end in a bucket of properly diluted Clorox solution between stalls. Have on hand a pump up spray bottle commonly used for spraying pesticides filled with dilute Clorox or some other disinfectant and use it freely on any areas that might become contaminated. After a sick horse gets well, strip out the stall and spray it down. Remove all organic matter from the stall walls such as dirt and manure and strip to bare stall floor. Ideally, leave this stall empty for 2 weeks but this is not always possible. Also disinfect the water buckets and feeders in that stall.
During this time period, it is recommended that no horses on the property leave or go to horse shows as you do not know who might be silently infected. Also avoid bringing new horses in unless you have an area separated for quarantine. Formerly sick horses should not be allowed into general population for at LEAST ten days after they show no symptoms. If the outbreak is a strangles outbreak, this time increases to one MONTH. This is likely the hardest part as they are usually going crazy by this time. If possible designate a pen or pasture as a sick turnout if it has no common areas near other horses. There needs to be at least 20 feet distance from other horse's areas and ideally more. After the outbreak has run its course this pen will have to be left empty for a month and even disked to remove infectious organisms. Even then it may still remain infected especially with a strangles outbreak.
All of these precautions need to be taken for three to four weeks after the last horse becomes well. With hard work and preparation and a little luck you can contain the illness to just a few horses. Shortcutting these recommendations will often lead to relapse of illness or more horses becoming ill. Follow all instructions given by your veterinarian and always finish all medications given. Don't stop medications just because the horse feels better.
Dr Angela Chenault owns La Paloma Equine Clinic and practices in Waller and the surrounding areas.