By Nora Grenager, VMD
Published in Bay Area Equestrian Network April 2007
Biosecurity is the undertaking of management practices that can reduce the risk of outbreaks and minimize the spread of infectious disease. Until fairly recently this word was not often associated with the horse industry even though many horse operations maintain some general biosecurity practices. However, recent infectious disease outbreaks (such as neurologic herpes virus and diarrhea caused by Salmonella) have brought to light the necessity for applying biosecurity practices, to some extent, at all horse facilities.
There are many aspects of the horse industry that make implementation of biosecurity practices potentially challenging. The horse population is increasingly mobile – horses travel to shows, clinics, go on trail rides, and even travel abroad. Many facilities have a transient resident population. There is also a lot of human traffic associated with horse facilities and events, and this is obviously an integral part of the industry. With an awareness of the importance of biosecurity, and a degree of conscientious planning, practical measures can be put in place that will benefit everyone in the long run.
There are numerous benefits of having a good biosecurity protocol at both an individual horse and facility-wide level. The most obvious benefit is the decrease in the risk of illness or death of a horse from infectious disease. This extends to include prevention of a stable-wide outbreak of infectious disease. Infectious disease has not only the potential to cause suffering, but it can be devastating emotionally and very expensive in terms of veterinary costs, loss of time in training, and even loss of event entrance fees. Decreasing the risk of an infectious disease is, therefore, valuable on many levels.
The most frequently implicated modes of infectious disease transmission are horse-to-horse contact, human and equipment contact, and wildlife and pests. Infectious diseases of concern affect a variety of different body systems and therefore have a wide range of clinical signs (symptoms). Special consideration should be given to the different categories of horses: pregnant mares, weanlings, yearlings, horses in training, geriatric horses, breeding stallions. Some diseases should be reported to the state veterinarian for tracking purposes, and some must be reported by law. There are a few infectious diseases that can be zoonotic, or transmitted from animals to humans.
Part of the Routine
It should become a habit to follow basic biosecurity measures as a part of your daily horse routine. Hand-washing is under-utilized as an indispensable way to control the spread of infectious disease. Wash your hands before and after working with each horse. Do not share equipment if possible – if necessary, clean and disinfect thoroughly between uses. Monitor and know your horse’s appetite, attitude, and manure production. Consult with your veterinarian if you have any concerns, as catching an illness early is pivotal in minimizing duration of illness and limiting the exposure of other horses. Maintain clean feed and water sources. Store feed in closed bins to prevent fecal contamination from other animals. Clean stalls as frequently as possible and dispose of manure promptly and properly. This not only limits the fecal-oral route of transmission but also decreases insect populations. Incorporate insect prevention into the daily routine; for example – frequent manure removal, feed-through insecticides, fly larvae predators, topical insecticides, good deworming programs, removal of any standing water.
Try to prevent nose-to-nose contact with unknown horses at events. Do not share equipment such as water or feed buckets, brushes, tack. Clean and disinfect your equipment and trailer prior to returning home. Ideally every horse should be isolated for 2 weeks after traveling to an event to prevent the spread of any infectious diseases to which the horse was possibly exposed at the event. If even one horse on the property travels, all the horses in contact with that horse should be up-to-date on vaccines. Consult with your veterinarian as to which vaccines your horse needs, as it can vary with geographic location, activity level, and age of horse.
Every new horse on the property should be isolated for 30 days. During this time, any evidence of illness (such as nasal discharge, cough, enlarged lymph nodes, inappetance, diarrhea) warrants consultation with your veterinarian. Ideally the rectal temperature should be obtained once daily because often an increased rectal temperature (greater than 101.5 o Fahrenheit) is the first detectable sign of illness. New horses should meet the vaccination and deworming recommendations or requirements of the facility. This may include having a negative Coggins test, or a recent health certificate.
It is important to have a plan on how to isolate sick horses that can be easily put into effect. The stress of having a sick horse does not need to be added to by inadequate planning. Length of isolation time will vary with type of illness.
As previously discussed, new horses, sick horses, and horses returning from traveling should all be isolated. “Restricted Access” signs should be posted at the clearly demarcated perimeter of the isolation area. Ideally, isolation stalls should be completely separate from the remainder of the horses, as some infectious diseases can be aerosolized and travel up to 50 meters.
Quarantined horses should be worked with after all the other horses on the property. Alternatively, or additionally, separate clothing and shoes should be worn when working with quarantined horses, or coveralls/disposable gowns and disposable booties should be worn. Hands should be washed before and after, and disposable gloves must be worn. All of these items can be kept in a plastic tub with a lid near the stall. A separate trash bag should be placed stall-side. Equipment should not be shared; the specified isolation equipment can be marked with colored tape to prevent confusion. If equipment must be shared it should be used last in the day and thoroughly cleaned and disinfected afterwards. A foot dip tub containing disinfectant at the entrance to the isolation facility is an excellent way to minimize foot traffic contamination. This tub can contain any one of a number of disinfectant types.
Hands should be washed for a minimum of 15 seconds with a pump-dispensed liquid soap. Alternatively, hands that are not visibly dirty can be cleaned with an alcohol-based (at least 62% ethyl alcohol) gel or foam disinfectant and allowed to dry.
Equipment and non-porous surfaces (metal, varnished wood, concrete, stall mats, etc.) should be thoroughly cleaned with a detergent (such as Tide ) and water (allow detergent to sit for 5-10 minutes), rinsed, then disinfected, followed by a final rinse. Equipment that cannot be effectively disinfected should not be shared between horses. Cloth items can be laundered and dried completely.
Disinfectant can be purchased at a veterinary or farm supply store. There are many types of disinfectants on the market. Choose one with which you are comfortable working, and that has documented efficacy in the presence of 10% organic matter. Diluted bleach (typically 2oz:1gallon of bleach:water but check the bottle as there are different concentrations available) is often used. It is very important to thoroughly clean with a detergent to remove organic debris (visible dirt and grime) otherwise disinfects are rendered ineffective. Be familiar with the proper safety precautions for the disinfectant you use and wear proper safety gear.
Manure and bedding from isolated horses should not be spread onto pastures or put into open air piles/pits. All infectious agents, not just organisms shed in the manure, can be spread via used bedding.
Formulating an effective and straightforward biosecurity protocol for your horse and facility is essential in this day and age of mobile horse and human populations. Routine daily biosecurity measures as well as isolation protocols for horses that are new, sick, or returning from travel is imperative. Infectious disease can cause loss of productive time, financial losses, and even loss of life. While the task of implementing a biosecurity protocol may seem daunting, the risks of not having one in place are even more so. Think about your situation and consult with your barn manager and veterinarian as to what will best suit your situation. Time spent now will minimize problems in the future.