Infectious Disease Part Two: Prevention

Keep your farm and family safe with Farm Biosecurity
by Dave Sauter, DVM

Last month Dr. Schwab reviewed five major infectious diseases that affect horses. This month we’ll examine methods and strategies aimed at preventing the movement of infectious disease onto your farm, otherwise known as Farm Biosecurity.

There are many reasons horses have to be hauled, including training, lessons, shows, breeding, racing, sales, trail riding and vacations, to mention just a few. The distances they travel are all across the map, from down the road a piece to across the country. Whether for business or pleasure, travel is part of life for most horses. Traveling does, however, create a pathway for transmission of infectious disease from the outside world to an individual farm.

Strategies that reduce the chance of bringing home unwanted pathogens begin before you leave the farm. They include items such as:

· Avoid compounding stressors. Travel causes stress that we have little or no control over; for example, the hours horses spend on their feet on the road, constantly making adjustments to maintain balance. They may be staying in strange facilities with unfamiliar horses, perhaps in far away locations with drastically different weather. The immune system is weakened by such stress, resulting in lower resistance to infection, and this comes at a critically vulnerable time (during travel) when there is increased exposure to pathogens. Many of our preventative medicine procedures also cause some temporary stress to the system, so plan ahead and schedule procedures such as vaccination, teeth floating, sheath cleaning and deworming at least three weeks prior to the scheduled event.

· Vaccinate appropriately and in a timely manner. Check your records or with your veterinarian to be sure the necessary vaccinations for the intended destination(s) are up to date. Vaccinations need to be given at least three weeks in advance to get the desired protective effect. Vaccination can, unfortunately, result in complications, such as fever and inflammation at the injection site. The three week minimum rule will allow enough time for recovery, just in case complications occur.

· Clean your supplies, tack and trailer prior to the trip. It is easier to keep things clean if they start out that way. Attention to cleanliness and hygiene is important at a time of heightened susceptibility to infection.

· Lighten up on grain meals a day or two prior to the trip. The digestive system is affected by travel. Lowering starch levels by reducing grain is beneficial.

· Make a checklist of supplies. Include such items as first aid kits (human and equine) and tools to pull a shoe. Consider bringing your own bedding, feed, water, buckets, and implements. Having a variety of dependable light sources can be invaluable as well.

· Begin monitoring your horse’s temperature before the trip, so you have a baseline.

When at the destination, check out the facilities. Probably the last thing you want to do when finally reaching your destination is inspect the stall, but it is important to take the time to ensure it is safe and secure. Strip the stall (horses love to eat strange, nasty bedding) and sweep out rodent and bird droppings that can harbor pathogens like Salmonella. Bed the stall with bedding from home that your horse is accustomed to. Knock down cobwebs (harbingers of pathogens). Check for nails sticking out of boards, remove any buckets and feed tubs and replace with your own, and check door latches. Discourage contact between your horse and other horses. Use your own tack and implements and avoid sharing them with others.

When an inanimate object acts as a vehicle to transport infectious material (e.g., mucus from an infected horse), it is referred to as a fomite. Don’t be a fomite. Just as tack and implements can carry infectious material on their surfaces, so can you. When you do come in contact with other horses, wash your hands afterward. A water hose is an excellent fomite, especially for diseases such as Strangles. Do not submerge water hoses into your water buckets; instead, fill them at a distance. Before heading home, clean supplies and tack again to avoid carrying infectious materials back to the farm.

Once you return home, it is ideal to separate the horses that traveled from the ones that didn’t. If possible, keep them separated for two weeks, monitoring and recording their temperatures daily. Ideally, new arrivals to a farm should be separated into yet another area for a 30-day period. Consider the separated areas potentially contagious, even if the horses appear outwardly normal. Organize chores so that the separated areas are the last you work on. Coveralls and different footwear can be put on as these isolated areas are entered, then removed when exiting. Keep separate implements, feed tubs, water buckets and water sources.

Cleaning and Disinfecting
Removing germs can be a challenge, especially in barns and trailers. Porous surfaces contaminated with soil and manure are particularly difficult. Although cleansers are not effective at killing bacteria, they can physically remove them, especially from non-porous surfaces. Use a detergent and a scrub brush to clean. Do not use a pressure washer because too much pressure will aerosolize contagious material, sending it into the air to circulate through the barn or trailer. A regular hose with a spray nozzle will generate adequate but not excessive pressure. After cleaning, allow surfaces to dry prior to disinfecting. Leftover water from cleaning will dilute the disinfectant, weakening its killing affect on the germs.

Not all disinfectants are created equal. Some, such as bleach, don’t work at all in the face of organic material. Its use should be limited to surfaces where nearly all organic material can be cleaned off first, such as shoes, buckets, grooming supplies, shovels, etc. Proper dilution of bleach for use as a disinfectant is 1 part bleach to 10 parts water, or three quarters of a cup of bleach to a gallon of water. Be sure to thoroughly rinse out feed tubs and water buckets after disinfecting them.

It is impossible to remove all organic material from some surfaces, such as stall walls, floors, floor mats, aisleways, etc., but there are disinfectants that are effective even when there is some organic material present, although these disinfectants can be more toxic and caustic. One example is Trifectant (peroxymonosulfate). With any disinfectant, carefully read the instructions to ensure the chemical is mixed and applied properly. Also follow label recommendations concerning protective gear and other safety issues. Do not mix chemicals.

Some diseases are zoonotic, which means they can pass from horse to human (e.g., Salmonella and MRSA). Planning ahead and good hygiene can help protect your farm, your horses and yourself.