When you ask most equine owners about controlling infectious diseases in their horses they say "Oh you mean do I vaccinate and worm my horses?" Certainly immunization of horses with vaccines to prevent or reduce the severity of certain diseases is a very important part of any infection control plan. However, equine owners must recognize that vaccination is only one part of a complete infection control plan. First, very few vaccines will protect 100% of the horses that receive them from the disease they are targeting and second there are diseases of the horse for which there are no licensed vaccines. The dewormers we have today appear to be generally effective, but there are opportunities to reduce parasitism even further by considering additional means of control. So what else can horse owners do to help protect their horses from infectious diseases?
There are two main components of an infection control plan. One part strives to optimize the horse's resistance to disease if exposed to the infectious agent. The second is targeted at preventing or reducing exposure of the horse to infectious agents. The details of such a control program must be tailored to each group of horses based on factors like age, use, housing, health status of the subject animals as well as that of other animals the horses commingle with, and risk tolerance of the manager/owner.
Many horses, like people today, live a fast paced life. Horses are on the road to shows, breeding farms, racetracks and trail rides. It is critical to manage each horse to avoid an illness that could compromise performance in the short run or even result in permanent impairment of their ability to perform or result in loss of life. An even larger impact would be felt by the equine manager/owner if an infectious disease outbreak occurs of their facility. If many horses become ill or a quarantine is imposed there can be a substantial financial loss due to cost of treatment, lost use and potentially loss of business if horses are unable to move on or off of the facility for a time. A facility that has had an infectious disease outbreak in their horses can become stigmatized which in turn can affect their business for a long period of time, even after the outbreak is resolved.
The first part of an infection control plan would be to take an inventory of the horses and other equids on the facility and assess the risk of infectious disease exposure based on what they do for a living. There are certain core or basic vaccines that all equids should receive. Beyond the core vaccines, the vaccination program needs to be tailored to the horses at a given facility. There is no one plan that fits all situations. Your veterinarian will be in the best position to consider all the necessary information about your horse's risk for exposure to disease agents and the most effective vaccination strategy to enhance their resistance to disease if exposed. The ultimate goal of vaccination is to maximize the horse's resistance to specific disease causing agents if exposed.
Another part of resistance to disease is so-called innate immunity or natural resistance. Since stress and nutritional deficiencies, especially trace mineral deficiencies, can result in degradation of innate immunity it is important to address these areas in the overall infection control plan. Assuring that the horse is as comfortable as possible during transportation and when housed can help to minimize the adverse effects of stress. The equine manager/owner should consider working with a professional to evaluate the diet to be certain not only meet the need for protein and energy but also meet the need for vitamins and minerals. These micronutrients can play a key role in resistance to disease. In addition consideration needs to be given to over all quality of the feed and how best to store and deliver it to the horses to minimize wastage and risk of contamination with feces from birds, rodents, other wildlife as well as other livestock and animals on the facility.
The other major part of an infection control plan should be focused on reducing or preventing exposure of the horse to infections. There is no question that this is the part that will require more thought and work on the equine manager/owner's part and will be more difficult to accomplish. So you might say "do I really need to do it?" Only you can answer the question of risk versus benefit of various options of an infection control plan.
It is important to recognize there are a multiple of ways to reduce exposure. One way to begin to develop the strategies to reduce risk is to think of how the horse would most likely be exposed and the disease agents of most concern. Some general methods of reducing exposure for various disease agents are similar but for certain diseases the program may need to be tailored in order to maximize on the control effort.
There is a guide to biosecurity for equine owners available from the USDA at the website http://www.aphis.usda.gov/publications
Dr. Josie Traub-Dargatz is a Professor of Equine Medicine at Colorado State University College of Veterinary Medicine and Biomedical Sciences.