Equine Infectious Diseases || Biosecurity and Control of Infectious Disease Outbreaks

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Infectious diseases have spread across continents with a devas-tating effect on animal populations. Accordingly, the veterinar-ian’s role in infectious disease prevention has been acknowledged for decades and is rooted in the management of rinderpest, which spread as a large epizootic in France in the mid-1700s and was the motivation for the creation of the first veterinary school, in 1762, in Lyons, France.1 In modern times, the emer-gence of zoonotic diseases (e.g., Hendra virus) and multidrug resistant bacteria (e.g., methicillin-resistant Staphylococcus aureus) can have a significant impact on animal and public health if unmitigated.

The importance of control measures for managing infectious diseases has been acknowledged for centuries, long before the modern microbiologic era. One of the first historical figures to observe physicians transmitting pathogens to patients was Ignaz Semmelweis, a Hungarian physician (1818-1865).2 In 1846, he deduced that medical students and physicians were trans mitting pathogens to patients (puerperal fever) because of a deficiency in hygiene procedures following postmortem examinations. The problem was solved when Dr. Semmelweis instituted the use of chlorinated lime antiseptic hand washes. This was no small feat. He had surmised that puerperal fever was spread by “pathogenic” causes, before the idea of pathogens even existed. Another historical figure in infection control was Florence Nightingale (1820-1910), who observed in 1863 a very high mortality rate in London hospitals and comparatively lower mortality rates in smaller provincial hospitals.3,4 She concluded that this difference was likely the result of patient overcrowding in London hospitals, leading to more efficient pathogen trans-mission. She was at the forefront of hospital surveillance for nosocomial infections.

More recently, the Study on the Efficacy of Nosocomial Infection Control (SENIC), conducted in U.S. human health-care facilities (1970-1976), found that implementation of an infection control program reduced nosocomial infections by an estimated 32%.5 This study specifically identified employment of trained infection control personnel, conducting surveillance activity, and having a system for reporting as important factors in the success of an infection control program. Although equiva-lent data for equine practices are currently not available, we can draw on the human hospital experience to improve veterinary infection control efforts.

Throughout this chapter, the term biosecurity is used inter-changeably with infection control to encompass all practices intended to prevent the introduction and spread of infectious disease agents within a population, as well as the containment and subsequent disinfection to remove or inactivate infectious materials.6 Traditionally, biosecurity focused on prevention of the introduction of an infectious agent into a population. Bio-containment, on the other hand, focused on controlling the spread of an infectious agent once it was introduced into a

population. Although this distinction is reasonably straightfor-ward, with respect to a farm or breeding facility, it is more difficult to separate biosecurity from biocontainment in the environment of an equine veterinary clinic, where disease agents are likely introduced on a daily basis, because an intended purpose of veterinary clinics is to treat sick animals. Having an infection control plan that includes screening of patients for the risk they may pose for pathogen introduction can mitigate this risk and will be a major topic discussed in this chapter.

Ethics of Infection Control

The veterinarian’s oath …

Being admitted to the profession of veterinary medicine, I sol-emnly swear to use my scientific knowledge and skills for the benefit of society through the protection of animal health and welfare, the prevention and relief of animal suffering, the con-servation of animal resources, the promotion of public health, and the advancement of medical knowledge. I will practice my profession conscientiously, with dignity, and in keeping with the principles of veterinary medical ethics. I accept as a lifelong obligation the continual improvement of my professional knowledge and competence.7

… underscores the ethical struggle of the veterinarian to protect the individual patient (relief of animal suffering), protect the animal population of the present and the future (protection of animal health and welfare), and protect people (promotion of public health). The practice of veterinary infection control embodies many of these competing responsibilities. However, in veterinary medicine, there is very little ethical framework on which to base biosecurity decisions. A recent workshop sup-ported by the Havemeyer Foundation brought together subject experts to address infection control concerns in equine popula-tions.8 Workshop participants agreed that to fulfill the ethical obligations of the profession, we must give due effort to infec-tion control, no matter if we are practicing in a hospital or field setting or caring for an individual animal or a population of animals. Although veterinary hospital infection control is in its infancy, a survey conducted in 2004 among North American veterinary teaching hospitals found that all 30 survey respon-dents had some type of infection control program in their equine hospitals, as did some of the more progressive private veterinary hospitals.3 As a profession, embracing the infection control movement allows us to meet the ethical obligations of the oath we have all taken.

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Biosecurity and Control of Infectious Disease OutbreaksBrandy A. Burgess and Josie L. Traub-Dargatz

C H A P T E R

531Chapter 62 Biosecurity and Control of Infectious Disease Outbreaks

state of Colorado veterinary medicine rules and regulations indicate that “all veterinarians must maintain a sanitary environ-ment in which they care for patients.”16 It further states that “if veterinarians work in clinics they do not own, they are respon-sible for ensuring that their work is done in a clean environment and within the standard of care.” Although this seems straight-forward, the standard of care relates to what a reasonable vet-erinary professional would do in a similar situation. The onus is on each of us to incorporate biosecurity in our practice of veterinary medicine.

Importance of Biosecurity

Infectious diseases can endanger the well-being of horses and personnel, in addition to having potentially devastating financial and emotional effects. A biosecurity or infection control program is intended to not only protect the patients and person-nel but is also meant to protect the veterinary hospital or practice. A survey of infection control programs at AVMA-accredited veterinary teaching hospitals (VTHs) found that outbreaks of nosocomial infections occur frequently and identi-fied zoonotic infections as an important occupational hazard to personnel.17 As such, a high standard of care cannot be attained without implementing strategies to control infectious diseases (i.e., biosecurity) for the protection of the people, the patients, and the practice.

Protect Patients

There is inherent risk of nosocomial infection for any hospital-ized patient. It is the veterinary hospital or practice’s obligation to implement strategies to minimize that risk. It is important to recognize that all nosocomial infections are not preventable, even in facilities employing excellent infection control practices and a high level of quality care for their patients. In a survey conducted among VTHs in 1997, 67% of 18 VTHs reported outbreaks of nosocomial disease between 1985 and 1996.6 In a more recent survey, 82% of 38 AVMA-accredited VTHs reported outbreaks of nosocomial infections in the previous 5 years.17

The Australian equine influenza epidemic of 2007 highlights that biosecurity is not just for protecting hospitalized patients, but it is also important for protecting animals on their home farms. During this outbreak, farms that employed some bio-security measures, such as the use of footbaths, were less likely to experience equine influenza on their farms.18 Ambulatory veterinarians must remain vigilant to reduce the risk of intro-ducing an infectious pathogen onto a client’s farm.

Protect Personnel

A report in 2001 indicated there are more than 1400 different infectious microorganisms known to be human pathogens, with 61% of those being zoonotic.19 Additionally, 75% of the esti-mated 175 emerging infectious agents were considered to be zoonotic.19 People working with animals, including veterinary personnel, have inherently increased risks of infection with zoonotic agents compared to the general public.20 However, members of the general public can also be at an increased risk when attending animal exhibits.21 Although a relatively small number of infectious diseases can be transmitted from horses to people, zoonotic infections can be devastating for those affected.22

Although the likelihood of acquiring a zoonotic infection from domestic animals is generally low, a number of known and emerging pathogens can affect both horses and humans. In the

Veterinarian’s Role in Biosecurity

As veterinarians, we are obligated to avoid unnecessary costs and to be transparent with respect to disease risks in patients and personnel. As such, infection control is fundamental to providing excellent patient care and a safe working environ-ment. Control of zoonotic diseases, those that can be transmit-ted between animals and humans, provides the opportunity for the physician and veterinarian to work together. However, opportunity does not always result in action. A study of Wis-consin physicians and veterinarians found that in general physi-cians are not very comfortable discussing zoonotic infections with patients; physicians felt that veterinarians should be involved in this dialogue, however, they infrequently engaged veterinarians in discussion of these diseases in their patients.9 Research shows physicians believe it is the responsibility of public health officials or veterinarians, whereas veterinarians believe it is the responsibility of physicians or public health officials.10 The veterinarian has a clear duty to recommend preventive measures to reduce the risk of zoonotic disease and to counsel clients to seek medical attention in the event of zoonotic disease exposure.11

Zoonotic diseases create the potential for liability for veteri-narians when owners or personnel interact with animals in the hospital environment where the responsibility for oversight of the welfare of the people involved rests with the veterinarian. The risk of zoonotic infection is becoming greater as the per-centage of the general public with compromised immune systems increases. The General Duty Clause, 5(a)(1), of the Occupational Safety and Health Act of 1970 stipulates employ-ers be responsible for employee safety, stating an employer must “furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.”12 This includes managing the risk of exposure to zoonotic agents. In a study of veterinarians in King County, WA, 28% reported having had a zoonotic infection, yet only 31% of practices had a written infection control policy.13 A survey of members of the American Veterinary Medical Asso-ciation (AVMA) found the majority were unaware of appropri-ate precautions needed to reduce the risk for zoonotic disease transmission.14 In a more recent survey of companion animal practitioners in Ontario, Canada, none of the 101 practices surveyed had a formalized infection control program and only 61% utilized control measures for infectious disease cases.15

Level of Biosecurity

In a recent workshop on infection control in equine popula-tions, participants agreed that there must be a minimum stan-dard for infection control when managing equine populations.8 The minimum standard is unique to each facility and takes into account the level of disease risk, the risk aversion of the stake-holders, and the standards set by the rules and regulations of the state’s board of veterinary medicine. It is important to recognize that disease risk, as well as risk aversion, may change through time. For example, there are periodic regional out-breaks of vesicular stomatitis (VS) in the area serviced by the Colorado State University Veterinary Teaching Hospital (CSU-VTH). During regional VS outbreaks, additional precautions are instituted with respect to history and examination of a patient prior to admission to the CSU-VTH. It is important for all veterinarians to become familiar with the rules and regula-tions of the state in which they practice because these in part establish a minimum standard of practice. For example, the

532 Section 6 Prevention and Control of Infectious Diseases

ecologic groups by means of mobile genetic elements such as plasmids, transposons, or bacteriophages. Theoretically, all uses of antimicrobial drugs have the potential to promote the evolu-tion of resistance in bacterial populations. Antimicrobial drugs can provide a survival advantage for resistant bacteria, thereby propagating genetic traits conferring resistance. Genes associ-ated with AMR to one antimicrobial can be linked to resistance genes for other antimicrobials promoting the development of multidrug resistant strains.46 Additionally, AMR can be linked to genes conferring resistance to disinfectants.47,48

As noted in human hospitals,49 many of the nosocomial pathogens associated with veterinary hospitals also are multi-drug resistant.50 This may be associated with high selection pressure applied through common use of antimicrobial drugs and disinfectants in the hospital environment.50,51 Several actions can be taken to minimize the impact of antimicrobial use. Although antimicrobial drugs should be used when needed (e.g., to treat horses with bacterial infections), they should be used judiciously.52,53 Inevitably, however, bacterial populations will be exposed to antimicrobial drugs and disinfectants in veterinary hospitals resulting in patient exposure to resistant microorganisms in the hospital environment. Therefore it is essential that appropriate infection control precautions be used to reduce the spread of resistance factors among microorgan-isms, to reduce the transmission of resistant organisms from patient to patient and between patients and personnel, and to reduce the likelihood of resistant bacteria becoming established in the hospital or farm environment.

Biosecurity Program Development

Every equine facility is unique with its own physical and opera-tional features. As such, a specific biosecurity program needs to be tailored to each facility. Although each program will be unique with respect to its finer details, they will all be based on overarching shared infection control principles. There are general systematic approaches, such as the Hazard Analysis and Critical Control Point (HACCP) system, which can aid in program development. The application of HACCP principles to biosecurity programs in veterinary hospitals and clinics has been previously described.6 Most of the examples in this section address veterinary clinics. However, the same general principles guiding design of a veterinary hospital infection control program can be applied to any equine facility, whether it is a boarding facility, a breeding farm, a private farm, or an equine event. Although the choice of policies governing infection control will vary between facilities, it is important that the policies are designed with all animals in mind, not only those suspected of having an infectious disease. Consideration should be given to the fact that in general the equine veterinary hospital popula-tion differs from the general equine population because hospital patients are more likely to be harboring an infectious disease and are more likely to be immune compromised. In addition, each patient is typically from a different herd, therefore, in a veterinary hospital environment, multiple herds are mixing.

Hazard Analysis/Identification

The first step in any control effort should be the identification of risks and hazards specific to the facility. Consideration should be given to pathogens that are zoonotic, foreign to the region, agents with a high nosocomial transmission risk, and those likely to have a major impact on patient management and welfare. In North America, pathogens likely to be important for equine facilities include Salmonella enterica, equine influenza virus, equine herpesviruses, Streptococcus equi subsp. equi, Clostridium

United States, three agents likely to pose a threat of zoonotic infection (particularly to immune-compromised individuals) are Salmonella enterica, Rhodococcus equi, and methicillin-resistant Staphylococcus aureus (MRSA).22 Rhodococcus equi, which is typically regarded as an equine-specific pathogen, was first reported to infect humans in 1967.23 Since then, there have been reports of respiratory infections in humans due to R. equi, with the most recent being pneumonia in an immune-compromised individual.23 It was not clear in this case if there had been any contact with horses or their environment. Methicillin-resistant Staphylococcus aureus infection in horses and the potential transmission between horses and people has also been described.24,25 Several equine viruses that cause encephalitis can affect both people and horses. Horses are usually “dead-end” hosts, with the exception of Venezuelan equine encephalitis (VEE), which can be transmitted from equids to humans.26 Although rabies occurs infrequently in horses, it should be considered a differential diagnosis in all cases of progressive neurologic disease in horses.27,28 There have been reports of horses developing rabies while at equine events that result in exposure risk to not only the owner and the attending veterinarian but also to the public attending such events and who might have had contact with the horse while visiting the stabling area. There have been reports of zoonotic transmission from a horse of Trichophyton equinum,29-31 Microsporum equinum,32 and Streptococcus equi subsp. zooepidemicus,33 further illustrating the necessity for an infection control program to include zoonotic disease agents transmitted by horses.

The emergence of Hendra virus in Australia dramatically demonstrated the importance of taking infection control pre-cautions when working with sick horses.34-37 One Hendra virus–associated human fatality was an individual who had assisted in the necropsy of affected horses.38 This incident emphasizes the importance of maintaining a minimum level of infection control as standard practice because it is likely that newly emerging and reemerging infectious agents will be encountered in the future.

Protect Hospital/Practice

Numerous reports of infectious disease outbreaks among equine veterinary hospital patient populations and in equine facilities have been reported.39-41 In a survey of infection control pro-grams at AVMA-accredited VTHs, 58% reporting outbreaks of nosocomial infections restricted patient admissions and 32% closed part of the facility to aid in mitigation efforts.17 One VTH, which closed because of an outbreak of Salmonella enterica serotype Newport, reported a financial loss of $4.12 million.42 This estimate likely does not include indirect costs related to loss of client-provider relationships; emotional stress; lost teaching opportunities for students, interns, and residents; diminished morale of hospital staff and clinicians; and poor public relations.

Judicious Antimicrobial Use

Judicious antimicrobial use should be an adjunct to infection control measures and not relied on as a primary preventive measure. Antimicrobial resistance (AMR) is an emerging problem that affects the ability to treat individual patients and the control of disease in animal populations and has significant public health implications.43

Controlling the emergence of AMR involves preventing pathogenic microorganisms from acquiring resistance, as well as preventing the spread of resistant organisms.44,45 Antimicrobial resistance arises from the interaction of bacteria and antimicro-bial agents. Drug resistance can evolve through the accumula-tion of chromosomal mutations or resistance genes can be transferred between bacteria from different taxonomic and


pathogen reservoirs but can also indicate overall protocol com-pliance and effectiveness.

Corrective Action Plan

Establishing a corrective action plan in response to recognized problems is central to an effective biosecurity program, allowing for an efficient and effective response. For example, if an out-break is recognized, the veterinary practice or hospital should have already considered the feasibility of restricting patient admission or closing the facility to aid mitigation efforts. If facility managers are unwilling to implement a corrective action then there is little purpose to having a formalized infection control program.

Evaluation of the Biosecurity Program

Determining the effectiveness of a biosecurity program will be specific to each facility. However, there are some basic princi-ples that can be applied in all facilities. Human health care has demonstrated that conducting surveillance and providing feed-back to personnel will not only enhance protocol compliance but can affect change in behavior (e.g., hand hygiene).54 It is important for facilities to consider how important “events,” such as fevers of unknown origin or catheter site infections, will be monitored to allow comparisons over time. In the age of com-puterized medical records, monitoring becomes much easier, especially if a facility incorporates important “events” into the record keeping system. For example, at the CSU-VTH, there is a section in the electronic medical record to note nosocomial infections, such as catheter site infections or surgical site infec-tions, or syndromes, such as respiratory disease, diarrhea, or fever. By tracking this information and regularly summarizing and reporting it to decision makers, a hospital or practice will be able to determine the effectiveness of the program. Particu-larly for a hospital or practice with a large staff, instituting a program oversight group to address any issues or concerns of the facility or personnel can aid biosecurity program manage-ment. For additional information, see the section on Monitoring Biosecurity Protocol Effectiveness.

Facility managers must keep in mind that a biosecurity program is dynamic in nature. It must be pliable enough to accommodate many different situations and must evolve with the facility, its patient population, its staffing situation, and the changing risk of infectious disease. For example, VS periodically occurs in livestock in the region serviced by the CSU-VTH. As such, appropriate precautions, including education of staff new to the area, are instituted during these periodic regional VS outbreaks.

Preventive Measures

An infection control program should strive to isolate or elimi-nate the source of infectious agents, reduce host susceptibility, and break the cycle of microorganism transmission.55 Unfortu-nately, in a veterinary hospital environment, we are generally caring for patients whose resistance to disease is compromised. As such, it becomes imperative to isolate the source of patho-genic microorganisms, thereby reducing the risk of transmission. There are several preventive measures that can be employed to this end, including rigorous hand hygiene, barrier nursing pre-cautions, movement restriction, patient isolation, and regular environmental monitoring and sanitation, just to name a few. Standard veterinary precautionary practices have recently been published.55 The efficacy of many of these practices in veteri-nary infection control have not been scientifically assessed;

difficile, rabies virus, rotavirus multidrug resistant bacteria such as MRSA, and endemic diseases considered reportable to the state or provincial animal health official such as equine infec-tious anemia (EIA), and those considered foreign to a region (e.g., pathogens causing equine piroplasmosis or contagious equine metritis in North America). The most important dis-eases will vary with the geographic location of an equine facility.

Critical Control Point Identification

The second step in designing a biosecurity program is to identify critical control points (CCP) or points at which a hazard can be prevented or minimized by applying a control measure. In an equine hospital, consider physical areas or processes in which transmission of pathogens is likely to occur and that might be preventable. Despite the existence of a large number of patho-gens that pose a potential threat to the well-being of horses and personnel, there are some common features in the way these pathogens are transmitted. For example, the control of gastro-intestinal and respiratory pathogens is commonly included in veterinary hospital biosecurity programs. Although there are likely multiple gastrointestinal pathogens of concern, in general, the mode of transmission is similar (i.e., fecal-oral route, contact transmission). As such, one CCP and prevention strategy may serve to mitigate the transmission risk of multiple different types of gastrointestinal pathogens. Identification of a physical area as a CCP will be facility specific. Consideration should be given to areas in which the most susceptible animals (e.g., severe disease, immune compromised, aged or young) and animals most likely to be shedding contagious pathogens (e.g., critical care or isolation units) are housed. In general, contact should be minimized between these patients and high-traffic areas such as patient receiving or examination areas. For an ambulatory practice, the CCP may be the practice vehicle and its supplies with the aim at reducing or preventing transmission of infectious agents between animals, as well as between facili-ties (see the section on Biosecurity in Equine Ambulatory Practice).

Critical Limits for Preventive Measures

A critical limit is a condition that must be met to prompt the preventive measure associated with a CCP. This may be as simple as requiring the isolation of a horse with diarrhea or as involved as closing a facility due to an equine herpesvirus 1 (EHV-1) outbreak. To aid in personnel compliance, consider formalizing the biosecurity program with a written document and providing training for those in the practice involved with patient care. Keep in mind that infection control procedures should be rigorous but not to the detriment of patient care and should not interfere with the ability to provide immediate medical attention to a patient.6

Critical Control Point Monitoring

Critical control point monitoring is essential to ensuring that a biosecurity program is effective. Monitoring can be as simple as monitoring the use of hand soap or hand sanitizer by tracking the amount of soap or sanitizer in containers provided through-out the hospital. It may entail tracking the occurrence of noso-comial infections, or it may involve active environmental surveillance. The level and type of monitoring will be specific to each facility and depend on stakeholder level of risk aversion and the available resources, both financial and personnel. It is important to note that conducting active surveillance for an organism, which survives relatively well in the environment, such as Salmonella enterica, not only can help identify important


measures to prevent infectious disease transmission.49,55,57,58 More detailed information on proper hand hygiene is available from the Center for Disease Control and Prevention (CDC).59 The simple act of handwashing mechanically reduces the organic debris and transient/resident microorganisms on the skin.55 With the addition of an antimicrobial soap, microorgan-isms can be killed or their growth inhibited.55,60 Personnel in contact with horses should maintain short fingernails to mini-mize accumulation of contaminants underneath fingernails and to facilitate effective hand hygiene. Additionally, they should also avoid wearing elaborate jewelry on their hands for both safety and hygiene reasons. Hands should be washed before and after attending each individual animal, regardless of glove use. Gloves are an adjunct to good hand hygiene practices not an alternative to good hand hygiene practices. Common contact areas (e.g., doorknobs, drawer or cabinet handles or contents, equipment, medical records) should not be touched with con-taminated hands or gloves. Although handwashing is an effec-tive way to reduce transmission of infectious agents, doing so frequently can compromise skin integrity, increasing the risk for bacterial colonization of hands and decreasing compliance with hand hygiene protocols.60 Consequently, it is important to provide not only soap and water but also lotions and moistur-izers for application after proper handwashing to promote healthy skin.

In addition to soap and water, alcohol-based hand sanitizers can provide a practical alternative. In health care settings, the CDC recommends the use of hand sanitizers containing 60% to 95% ethyl or isopropyl alcohol.61 Alcohol-based hand sani-tizers are as effective as or more effective than handwashing at reducing bacterial contamination on hands after performing routine physical examinations on normal horses.62 Alcohol-based hand sanitizers can also be used when soap and running water is not readily available, such as stall-side during a sport-ing event or during horse transit, although they are not as effective in the presence of organic debris.55 Dispensers for hand-sanitizing solutions can be easily installed and their fre-quent use should be encouraged to minimize potential spread of infectious agents. Extrapolating from human health care, the costs associated with the use of alcohol-based hand sanitizers can be greater than costs associated with handwashing prod-ucts, but the added benefit of enhanced compliance can be immeasurable.63

The bottom line is that, when hands are soiled, soap and water is recommended. In situations in which soap and water are not available or if hands are not grossly soiled, then an alcohol-based product can be used for hand hygiene. Alcohol-based products can be especially useful for frequent hand hygiene, at those times when skin is likely to become compro-mised as the result of frequent handwashing (i.e., chapped and cracked) or in an ambulatory practice when running water may be unavailable.

Barrier Nursing Precautions

There is evidence that barrier precautions can prevent the trans-mission of infectious agents64 (Fig. 62-1). The intent is to impose a barrier between “clean” and “dirty,” thereby preventing the contamination of footwear, skin, or clothing of personnel with an infectious agent found in the environment or shed by patients.65 This may be done to minimize the spread of an infec-tious agent to uninfected patients/personnel or to reduce expo-sure of immune-compromised patients/personnel to pathogens. In most situations, barrier precautions are effective if they are implemented by informed staff and all personnel understand the rationale behind their use. In veterinary settings, barrier nursing precautions usually include the use of disposable gowns, gloves, facial protection, and implementation of footwear

nevertheless we are able to draw from knowledge gained in the field of infection control in human health care. It is important when extrapolating from human health care to keep in mind that the level of environmental contamination is typically much greater in veterinary hospitals than in human health care facilities.

Transmission Routes

In general, transmission of microorganisms can occur via contact (indirect or direct), aerosol/droplet formation, or be vector borne. Many preventive measures are intended to disrupt one or more of these transmission routes. Direct contact may involve animal to animal or animal to personnel contact. This contact can likely be prevented through the use of separation or barrier nursing precautions. Indirect contact occurs when an infectious agent is carried by personnel or an inanimate object from the infected animal to an uninfected animal or person. Prevention may include adherence to rigorous hand hygiene protocols, barrier nursing precautions, or the use of dedicated equipment for infectious disease cases. Aerosol transmission occurs with particles <5 µm in size, which can remain airborne for some time and even travel a relatively long distance.56 Prevention of aerosol transmission can be a challenge and typically will include isolating the infected animal in its own air space. If this is unattainable, consider maintaining a significant separation between patients. Droplet transmission occurs with larger par-ticles, which are generated during coughing and sneezing or during diagnostic procedures such as draining an abscess, wound irrigation, or performing endoscopy. Droplets generally do not remain airborne for any significant length of time and typically only travel short distances from the source. Maintaining separa-tion between patients, using barrier nursing precautions, and performing procedures in low-traffic areas will likely be effec-tive at preventing this type of transmission. Vector-borne transmission is associated with flies, ticks, and mosquitoes. Implementing an insect and tick control program will be impor-tant in reducing this transmission route. Patients should be examined for lice and ticks and, if found, should be treated to reduce the risk of transmission. If other health concerns pre-clude treatment, these patients should be segregated from the general hospital population and provided with dedicated grooming equipment.

Daily Attire

Daily attire for hospital personnel should be neat, clean, and professional. Footwear must be safe, protective, and cleanable and constructed of a nonporous material. Closed-toe footwear is strongly recommended for all hospital personnel. Standard protective outerwear (e.g., smock, coveralls) should be neat and clean, with an adequate supply on hand to allow personnel to change when outerwear becomes contaminated. Hospital attire should not be worn outside the clinic or field service environ-ment. Personnel should be encouraged to wear hospital-dedicated clothing and footwear, especially in high-risk areas such as isolation, intensive care units, or foaling facilities. Des-ignated surgical scrub clothes and dedicated footwear or protec-tive shoe covers should be worn while working in surgery areas and should not be worn beyond the changing area for the surgery suite.

Hand Hygiene

Proper hand hygiene, including washing with soap and water, as well as using alcohol-based hand sanitizers, is a proven aid to preventing transmission of infectious agents and widely accepted as one of the most important infection control


mouth) to infectious materials. Consideration should be given to implementing their use anytime there may be a splash or a spray (e.g., flushing wounds, draining abscesses, performing a necropsy, or disinfecting a stall).

Footwear HygieneFootwear hygiene includes donning rubber overboots or dispos-able footwear covers and the use of disinfectant footbaths or footmats. It is imperative that footwear be clean prior to moving to a new environment, whether another area of the veterinary hospital or another equine facility when on ambulatory calls. As such, personnel should be required to wear close-toed shoes when working with animals in the practice of veterinary medi-cine. Footwear should also be easily cleaned, especially the soles, and there may be additional requirements for safety reasons (e.g., to wear boots that would be more protective if the person was stepped on by the patient). The policy regarding footwear type required for employment in the practice will be practice specific (see the section on Footbaths/Footmats for further information). When caring for high-risk cases, such as those in isolation, neonatal foals, or immune-compromised patients, footwear should be of a type that can be fully disinfected or dedicated to care for an individual case. Care should be taken not to contaminate one’s hands or clothing when taking off protective garments. All personnel must be aware of which areas or materials are thought to have a different likelihood of contamination (i.e., the distinction between “clean” and “dirty”) and make every effort to keep “clean” areas (including clothing, equipment, and supplies) free of contamination. It is equally important for all personnel to be able to recognize when con-tamination might have occurred so that appropriate actions can be taken to avoid transmission of the contaminants to another area (e.g., change of clothing, disinfection of contaminated sup-plies, and disinfection of hands).

Movement Restriction and Traffic Flow Management (Personnel, Patients, Visitors)

A very simple way to disrupt pathogen transmission is to manage traffic flow and restrict movement of both animals and humans, including personnel and visitors. In general, traffic should flow from clean areas to dirty areas and from low-pathogen risk to high-risk situations and patients. The presence of visitors in any equine facility should be assessed with regard to the risk they pose to the facility and the need for such visita-tion. In some areas (e.g., isolation area), it may be better to restrict visitation. In a situation in which some traffic is unavoid-able, it can be minimized and more closely monitored by estab-lishing visiting hours and requiring all visitors to check-in to the facility/hospital. Consideration should be given to implement-ing rules governing visitation by young children. The actions of young children can be more difficult to predict and control, and therefore they can pose more biosecurity risk, as well as be more at risk of exposure to pathogens than adult visitors. Special consideration should be given to visitors that have recently been in foreign countries (e.g., within the previous 72 hours).

Separation and Isolation

Separation and isolation are methods used to contain and disrupt the transmission of infectious agents to patients and personnel. The intent is to contain environmental contamina-tion and reduce the likelihood of contact between patients, thereby reducing the likelihood of pathogen transmission to the general patient population. Dedicated equipment for animal management (i.e., buckets, halters), as well as for stall cleaning (i.e., pitch fork, shovel, dumpsters, or rubbish bins), is a part of maintaining separation or isolation of infectious disease cases.

hygiene (i.e., footwear covers, rubber boots or use of footbaths or footmats).

GownsThe use of nonsterile gowns can be an effective means to main-taining a barrier between “clean” and “dirty” or between immune-compromised patients and the rest of the hospital population. Gowns may be permeable, which are typically used for general animal care, or impermeable, which are recommended for use when splashes are expected (e.g., flushing wounds, draining abscesses, or delivering a foal). If using disposable gowns, it is not recommended to reuse them, even on the same patient. Some facilities will invest in washable fabric gowns that should be laundered before using on different patients. In general, when wearing barrier gowns, it is advisable to also wear gloves. When donning and doffing gowns, the wearer must take care to only touch the outside of the gown with gloved hands, limiting the chance for cross-contamination.

GlovesGlove use can be an important part of creating a barrier and minimizing infectious agent transmission.66 They are intended to be used for a single patient or patient group and should be worn when contacting feces or other bodily fluids. Gloves should be discarded and hands washed prior to accessing supply drawers, common equipment such as computers or phones, using a stethoscope, handling another patient, or touching another surface such as a doorknob. It is important to remember that gloves are not an alternative to good hand hygiene, rather they are an adjunct to hand hygiene. In human health care, it has been reported that only 22% of glove leaks were recognized by the wearer.66 This emphasizes the need to still perform adequate handwashing after glove removal. In general, good hand hygiene will likely suffice when working with healthy horses, but gloves should be incorporated when handling a horse suspected or confirmed to have an infectious disease. Additionally, consideration should be given to double gloving when collecting samples from a patient in isolation or when glove contamination is expected. This will allow the wearer to remove the outer contaminated pair of gloves before labeling samples or removing boot covers or barrier gowns.

Facial ProtectionFacial protection (i.e., face shield) is intended to prevent the exposure of mucous membranes (including eyes, nose, and

Figure 62-1 Student working with horse using barrier nursing precautions in the main hospital at the CSU-VTH. The student is wearing disposable gloves and a disposable gown. The chain barricade is placed around the stall to limit traffic, and a disinfectant foot mat is placed at the entry to the stall.


such as training, breeding, or boarding facilities. It is important to identify such patients even if they are not being examined for an infectious disease problem because they may still pose a risk. For example, a foal being hospitalized for an umbilical hernia repair that has a fever, purulent nasal discharge, or enlarged submandibular lymph nodes should be handled as an infectious disease–risk patient. When referring a patient, the practitioner should inform the referral hospital of any suspected infectious diseases and clearly indicate this on patient records so appropriate precautions can be taken.

Footbaths/Footmats

Footwear hygiene is an important component of a comprehen-sive infection control program. Footbaths or footmats should be considered for use in traffic areas where personnel will be moving between groups of animals of different status (e.g., between colic patients and the general equine hospital popula-tion). All personnel should be instructed to use every footbath or footmat when encountered.

The use of footbaths is a common component of infection control programs in VTHs. In a survey of 31 VTHs in the United States and Canada, 97% reported using disinfectant footbaths within the facility.67 Footbaths should be considered whenever soiling (e.g., with feces, nasal secretions, or uterine discharge) of footwear is likely and may necessitate the use of rubber boots that can readily be worn into footbaths. Footwear or rubber boots should be kept clean at all times when moving between patients. The efficacy of a footbath depends on a number of factors, including frequency of changing disinfectant, amount of organic debris on footwear, the type of disinfectant used, and compliance for use by hospital personnel. Among 30 VTHs that reported the use of disinfectant footbaths, 68% used a single type of disinfectant solution and 32% reported using more than one type of disinfectant solution (in footbaths in different locations, not mixed in the same footbath).67 The disinfectants most often used in footbaths were quaternary ammonium compounds (42%) and phenolics (39%), followed by hypochlorite solutions (23%) and peroxygens (19%). Other disinfectants used in footbaths were povidone-iodine, chlorhex-idine, and ammonia-based products (3% per each). In one study, a 1% Virkon® (Virkon-S, Antec International, a DuPont Company, Sudbury, Suffolk, United Kingdom) footbath, used under conditions typically encountered in the large animal vet-erinary hospital, found bacterial concentrations on contami-nated rubber boots to be 67% to 78% lower than untreated boots.67 In addition to footbaths, 26% of 31 VTHs also reported using disinfectant footmats in some locations.67 Although more expensive than traditional footbaths, improved compliance is likely because mats can be used without the requirement for rubber boots. In a study evaluating the efficacy of a peroxygen disinfectant (Virkon S), footmats were as effective as footbaths, with mean bacterial counts 1.3 to 1.4 log10 lower than untreated rubber boots.68

Use of dedicated hospital footwear should be recommended to all those personnel with patient contact to minimize the possibility of trafficking pathogens to or from the veterinary hospital. Additionally, footwear hygiene protocol compliance may be improved because personnel may be more inclined to step onto a disinfectant mat if they are not wearing fashion or athletic footwear. Some practitioners prefer to use disposable plastic footwear covers instead of footbaths or footmats to minimize risk of spreading disease agents on footwear. Although the relative efficacy of this method has not been documented, footwear cover durability has been evaluated and was depen-dent on the product worn, as well as the type of surface and distance walked.69 Most likely, any method will be effective at minimizing the movement of pathogens, provided it is properly

SeparationSeparation refers to the establishment of hospital areas with differing levels of biosecurity. This may be related to the species (e.g., horses and cattle), to the type of animal (e.g., mare or foal), to the severity of disease (e.g., colic, systemic disease, or elective surgery cases), or to the type of patient (i.e., inpatient versus outpatient). The degree of separation that can be achieved will be dictated by the physical and operational limita-tions of the facility. Commonly designated hospital areas include large and small animal facilities (in a mixed-animal practice), critical care units, and isolation units. Similar divisions can also be applied to home premises. For example, on a breeding farm, areas may include those that house pregnant mares, foaling mares, mares and foals, weanlings, yearlings, and horses in train-ing or competition. Personnel and equipment movement between different hospital/farm areas should be limited or pro-hibited. If movement of personnel or equipment is to occur, it should be governed by clearly defined biosecurity protocols (e.g., use of protective clothing, hand hygiene, and disinfection of equipment between areas).

IsolationPatients with suspect or confirmed infectious disease should be evaluated and managed in an area isolated or segregated from the main hospital population. In general, infectious disease cases include patients with gastrointestinal disease (e.g., colitis or enteritis), acute onset of respiratory disease (especially if febrile), abortion/fetal loss, neonatal foal death or disease, exces-sive salivation/oral ulceration, skin lesions with hair loss, fever with or without other clinical signs, or acute-onset neurologic disease. If it is necessary to utilize the main hospital facilities or equipment (e.g., radiology, surgery, endoscopy) for diagnostics or treatment of an infectious disease suspect, these should be done at the end of the day, thoroughly cleaning and disinfecting immediately after use. It may be helpful to establish a policy for mandatory testing of all hospitalized animals that develop specified clinical signs. A few examples include requiring Salmonella fecal culture of animals with fever, diarrhea, or leuko-penia; rapid influenza testing of animals with fever and cough; and bacterial cultures for S. equi subsp. equi of animals with clinical signs of respiratory disease from farms with a history of strangles. It is important to gather historical information not only on the patient but also on the herd of origin. Determina-tion of disease status will allow for more effective management of the infectious disease risk both in the hospital, as well as on the home operation.

Part of isolating an infectious disease suspect or confirmed case is to also minimize personnel traffic into isolation areas. Facilities should consider employing dedicated personnel to manage such cases. Although this is likely costly, it will greatly reduce the likelihood of contagious disease transmission caused by personnel movement. Another option is to install video surveillance systems with remote computer access. Video sur-veillance has the added benefit of patient monitoring without having to enter the isolation area. Reducing the number of high-risk contacts with infectious disease cases will also reduce the likelihood of pathogen transmission to personnel or patients.

Every effort should be made to minimize contact between patients with a history or clinical signs suggestive of infectious disease and the general hospital population, as well as to mini-mize the time spent in common areas. Acquiring a thorough history before admission can often help route a patient to the most appropriate location on arrival at the clinic. For example, the index of suspicion for infectious respiratory disease should be increased for patients with recent onset of fever, ocular or nasal discharge, or frequent coughing. This is particularly true if the animal is from a facility with a mobile equine population


implemented and consistently used by all personnel. Factors, such as cost-effectiveness and convenience, are likely to influ-ence which method is preferred.

Enhancing Biosecurity Protocol Compliance

Compliance to biosecurity protocol is critical to the success of an infection control program, yet it is one of the most challeng-ing aspects of program implementation within a veterinary practice. Providing personnel with the education and training to fully understand and practice the infection control policies is integral to program compliance. One method to encourage protocol compliance lies within the program itself. By regularly reporting results from environmental monitoring or nosocomial infection tracking, personnel will be repeatedly reminded that compliance with biosecurity protocols is critically important. Empowering personnel to become a part of program develop-ment will encourage active participation in its implementation. By creating an infection control committee, personnel will have an avenue to provide feedback, including lapses in protocol compliance, as well as recommendations for program improve-ment. However, there should be one individual within the practice who not only conducts a regular assessment of data but also has the ability to make decisions with respect to infection control measures in an emergency. Part of infection control program development is determining how the practice will manage protocol noncompliance: rewarding excellent compli-ance or penalizing poor compliance with the loss of hospital privileges, or both. Personnel should be reminded that the program has been implemented to protect people, patients, and the practice and is necessary to provide optimal patient care. A biosecurity program based on sound principles is only as good as those practicing the infection control measures agreed on by the practice decision makers.

Environmental Infection Control

Effective cleaning and disinfection are critical for breaking the transmission cycles of infectious agents. Although cleaning alone can reduce the bacterial load by 90% on a concrete surface, following up with disinfection will kill an additional 6%.70 Cleaning and disinfection is a multistep process involving the removal of visible debris, scrubbing the area with detergent, followed by rinsing and application of an appropriate disinfec-tant at the correct dilution and for the recommended contact time.

CleaningIt is imperative that all surfaces are thoroughly cleaned before any disinfectant is applied. All visible organic debris, such as feces, urine, uterine fluid, nasal exudate, and blood, should be removed prior to disinfection because their presence com-monly reduces product efficacy. Many bacteria, when in the environment, are very efficient at forming biofilms (organized bacterial communities that secrete a protective extracellular matrix) that adhere to surfaces. Biofilm formation enhances bacterial survival from a variety of environmental insults, including disinfectants and other antimicrobial treatments.71-73 Bacteria in biofilms survive well in the environment, providing a continuous source of pathogens that can cause nosocomial infections. Scrubbing surfaces with detergents will aid in removal of debris and biofilm. With this in mind, it is critical that cleanable surfaces be maintained throughout equine facili-ties and in particular throughout veterinary hospitals. Dirt floors or porous surfaces (e.g., untreated wood) should be avoided as these cannot be effectively disinfected.70 If porous surfaces are present, they can be rendered less so by painting or sealing the surface.70,74

DisinfectionDisinfection refers to the reduction of viable microorganisms on a surface. After appropriate cleaning and rinsing, apply a disinfectant effective against the microorganism(s) of concern, ensuring that the concentration and contact time are in accor-dance with label directions. A number of commercial products are available for environmental disinfection. It is beyond the scope of this chapter to review all available products, but it is important for personnel responsible for choosing these products to be familiar with major classes of disinfectants, their efficacy against different pathogens, and conditions that limit their effectiveness70 (Table 62-1). Environmental conditions, includ-ing ultraviolet (UV) light (i.e., sunlight) and temperature can greatly affect the efficacy of many products, thus consideration of these factors is important when disinfectants are applied in areas that are not climate controlled. Additionally, it is impor-tant to ensure that the products being used are registered with the U.S. Environmental Protection Agency (EPA) and that all safety precautions recommended by the manufacturer are being followed. All disinfectants should be stored in a safe place, particularly when access by children or domestic pets is possi-ble. In addition to traditional surface disinfection, aerosol appli-cation or “directed misting” with a disinfectant can be considered for control of airborne infectious agents or difficult-to-reach areas such as ceilings or overhead areas75,76 (Fig. 62-2). This approach is not a panacea and does not negate the importance of appropriate cleaning, but it may be a useful adjunct to clean-ing and more traditional methods of disinfection. The use of aerosolized compounds should be performed with appropriate respiratory protection for personnel and compliance with all other safety recommendations.

Proper cleaning and disinfection should be employed regu-larly in areas used to house and manage all patients, not just areas housing patients with suspected or confirmed infectious diseases. At a minimum, all stalls should be cleaned and disin-fected between patients. Routine cleaning and disinfection helps to minimize the bacterial burden in the environment and the accumulation of resistant flora that may serve as a source of antimicrobial resistance genes (see the section Antimicrobial Resistance). Special attention to cleaning and disinfection should be employed for areas known to have housed patients with suspected or confirmed infectious diseases. All areas used in the management of these patients (e.g., examination rooms, stocks, surgery suites, stalls, trailers) should be cleaned and disinfected immediately after use to minimize inadvertently tracking pathogens from contaminated to clean areas. It is critical that any equipment in contact with animals with an infectious disease be cleaned and disinfected before reuse and that these items be handled to prevent contamination of hos-pital surfaces. For example, a rectal thermometer used to check the temperature of a horse with salmonellosis can become contaminated, thereby contaminating the hands of personnel, as well as any surface it contacts, if not promptly cleaned and disinfected or discarded.39

Waste Management and Disposal

Waste management is an important part of a comprehensive infection control program. The AVMA has previously published general guidelines to aid veterinary practices in developing waste management programs.77 However, every veterinary prac-tice must develop a program in compliance with federal, state, and local laws and regulations.78 The federal Medical Waste Tracking Act of 1988 (MWTA), regulated by the EPA, applies to veterinary medical waste considered to be a public health hazard. Medical and infectious waste is defined by state laws and regulations. In general, the definition will include factors such as infectivity, waste categories (e.g., sharps, tubing, fecal


deter patient access to waste containers during stall cleaning. Appropriate disposal methods, such as autoclaving and incinera-tion, will depend on the suspected infectious agent, as well as local regulations. Proper disinfection of equine bedding often becomes problematic because of large volumes. Effective methods may include autoclaving, composting, landfill disposal, or steaming.

The bottom line is that, prior to disposal, veterinary medical waste should be treated in accordance with state and local rules and regulations to eliminate the threat of pathogen trans-mission to other animals and to protect public health and the environment.

Wildlife Reservoirs

Control of insects, ticks, rodents, and other wildlife is an impor-tant part of a biosecurity program at equine hospitals. Both

waste), and which facilities are required to comply with these regulations (“the generator”).77 Veterinary hospitals should sep-arate waste as it is generated; contain it in a manner that will protect waste handlers, the public, and patients; and label it appropriately.77 It is important to note that according to the MWTA, waste generators are liable for medical waste from its creation to final disposal, regardless of the employ of a waste management company.

Waste from infectious patients, as well as any waste harbor-ing an agent capable of having an adverse effect on other animals or public health, is specifically a concern for animal facilities. This can include materials such as needles, bandages, or bedding contaminated with bodily excretions (e.g., nasal exudates, urine, feces, or blood). Transmission can occur through mechanical transfer by footwear, hands, or shared equipment (e.g., stall-cleaning equipment) or via biologic vectors such as rodents, insects, or clinic cats or dogs. Care should be taken to

Table 62-1 Common Antiseptics and Disinfectants Used in Veterinary Practice

Activity in Organic Debris Spectrum of Activity Limited Activity No Activity Comments

Antiseptic*Alcohol Rapidly

inactivatedGram-positive bacteriaGram-negative bacteriaMycobacteriumFungal organismsEnveloped viruses

NA Nonenveloped virusesCryptosporidiumBacterial spores (static)

Not used for environmental disinfectionMinimally toxicFast acting with no residual activityRequires water for activity (70% solution)

Biguanide (e.g., chlorhexidine)

Rapidly inactivated

Gram-positive bacteriaEnveloped viruses

Gram-negative bacteria

Fungal organisms

Nonenveloped virusesCryptosporidiumBacterial spores (static)Mycobacterium

Not used for environmental disinfectionMinimally toxicBactericidal when used on skinResidual activity

Povidone iodine Moderate Gram-positive bacteriaGram-negative bacteriaFungal organismsMycobacterium

Enveloped viruses

Nonenveloped virusesBacterial sporesCryptosporidium

Not for environmental disinfectionUseful on tissueMinimally toxicHigher concentrations have decreased

activity

Disinfectant*Peroxygen Very good Gram-positive bacteria

Gram-negative bacteriaFungal organismsEnveloped virusesNonenveloped virusesProtozoa

CryptosporidiumBacterial sporesMycobacterium

NA Good environmental disinfectantMinimally toxicRapid actionCan be corrosive to metal/concrete

Phenol Very good Gram-positive bacteriaGram-negative bacteriaEnveloped viruses

Fungal organisms

Nonenveloped viruses

Mycobacterium

Bacterial spores (static)Cryptosporidium

Environmental disinfectantIrritating to skin and mucous membranesToxic to cats and pigsMinimal residual activityNoncorrosive

Quaternary ammonium

Moderate Gram-positive bacteriaGram-negative bacteriaFungal organismsEnveloped viruses

Nonenveloped viruses

CryptosporidiumBacterial spores (static)Mycobacterium

Good for environmental disinfectionMinimally toxicMinimal residual activityInactivated by anionic detergentsLess effective at low temperatures and

low pHNoncorrosive

Sodium hypochlorite

Rapidly inactivated

Gram-positive bacteriaGram-negative bacteriaEnveloped virusesNonenveloped virusesMycobacteriumBacterial spores

NA Cryptosporidium Fair for environmental disinfectionMinimal residual activityInactivated by cationic detergents and

sunlightLess effective at low temperatures and

high pHChlorine gas generated if mixed with

other chemicalsCorrosive to metals

Data from Block SS, editor: Disinfection, sterilization, and preservation, ed 5, Philadelphia, 2001, Lippincott, Williams & Wilkins. Linton AH, Hugo WB, Russell AD, editors: Disinfection in veterinary and farm animal practice, Oxford, 1987, Blackwell Scientific Publications. Morley PS: Vet Clin North Am Food Anim Pract 18:133, 2002; Morley PS, Weese JS: Biosecurity and infection control in large animal practice. In Smith BP, editor: Large animal internal medicine, ed 4, St. Louis, 2009, Mosby Elsevier.

NA, Nonapplicable.

*Follow label directions for appropriate dilutions and safety precautions.


or the occurrence of nosocomial infections as part of a surveil-lance program can promote hospital personnel awareness of the potential hazards of reduced biosecurity efforts and encourage continued compliance with biosecurity protocols. The principle of surveillance and monitoring for control of nosocomial infec-tions in veterinary hospitals has been previously described in detail.6,94,95

Patient MonitoringThe ultimate goal of a comprehensive surveillance system is to detect all occurrences of nosocomial infection and disease. However, achieving such a goal may not be possible because of limited resources or diagnostic modalities. A number of methods can be employed to monitor for nosocomial infections among hospitalized patients, including weekly clinician rounds, regular analysis of computerized clinical data for predefined clinical signs (i.e., syndromic surveillance), or full microbiologic moni-toring for specific agents. The principles behind syndromic sur-veillance include monitoring of clinical signs suggestive of infection in hospitalized patients without specific microbiologic diagnosis. Syndromic surveillance can be incorporated into a computerized medical record system so that any trends (e.g., increased frequency of catheter-associated infections, fever in hospitalized patients) can be quickly recognized. This will allow the person overseeing the biosecurity program to further inves-tigate and potentially implement corrective actions before the situation escalates. Monitoring patients and providing feedback to stakeholders can result in increased awareness among hospi-tal personnel and improved compliance with infection control protocols, thus enhancing program effectiveness beyond the disease being surveyed.

Experience with infection control in human health care set-tings also suggests that it is possible to be more efficient and as effective if specific high-risk or high-cost problems are tar-geted.54 As such, targeted surveillance is more often used in human health care facilities and is becoming more commonly used in veterinary hospitals. It allows a facility to focus its efforts on a particular type of patient (e.g., all patients versus inpatients versus critical care patients), a specific pathogen (e.g., Salmonella or MRSA), or a specific syndrome (e.g., colic, diarrheic, or febrile patients). Patient monitoring may be an active process (e.g., performing fecal cultures on all inpatients on admission for Salmonella) or a passive process (e.g., summarizing labora-tory tests to identify MRSA isolates). The specific focus and methods for surveillance need to be matched to the needs and resources of each facility while accommodating their level of risk aversion. The major benefit of targeted surveillance is the decreased cost of and effort needed for data collection. The downside is an inability to detect potential problems in patients that are not being monitored and an inability to make an etio-logic diagnosis.

A combination of different monitoring methods can be used in patient surveillance. For example, at the CSU-VTH, all large animal inpatients are monitored for Salmonella shedding based on fecal cultures performed twice weekly throughout the period of hospitalization. Other potential nosocomial infections are passively monitored based on syndromic surveillance, which may or may not be followed-up with bacteriologic cultures. The type of patient monitoring to incorporate into a biosecurity program will be facility specific and likely reflect the availability of resources, the level of risk aversion of the stakeholders, previ-ous disease outbreak experiences, and disease prevalence in the area.

Environmental MonitoringEnvironmental monitoring is used to assess veterinary biosecu-rity program effectiveness and contributes to the comprehen-siveness of a biosecurity program.94,96 Contamination of the

insects (e.g., flies and mosquitoes) and rodents (e.g., mice, rats) can serve as biologic or mechanical vectors for dissemination of pathogens.36,39 Similarly, pets, such as clinic cats or dogs, can serve as biologic or mechanical vectors for infectious agents, as well as a source of antimicrobial-resistant bacteria.79,80 Previous epidemiologic investigations have linked cats to Salmonella enterica outbreaks,81 and other reports suggest a clinic cat to reduce the risk of Salmonella transmission based on their impact on rodent and wild birds in the hospital.82 Wildlife can also serve as a source of pathogens for domestic animals, for example, feces of the opossum may contain the infective form of Sarcocystis neurona, which is the causative agent for equine protozoal myeloencephalitis (EPM).83 West Nile virus is spread via mos-quito bites,84,85 EIA is spread by tabanid flies,86 flies have been shown to carry Salmonella,87-89 and certain insects are proposed vectors for the spread of vesicular stomatitis virus.90,91 For this reason, pest management should be incorporated into a com-prehensive infection control program.

Monitoring Biosecurity Protocol Effectiveness

A comprehensive infection control program includes monitor-ing the effectiveness of implemented protocols through patient and environmental assessment. There are multiple reasons to monitor an infection control program, including assessing its effectiveness and efficiency, as well as to provide feedback to stakeholders as a means of enhancing protocol compliance. With the emergence and reemergence of infectious diseases, it is imperative to ensure existing protocols are adequate. Moni-toring may lead to a permanent policy change or to a temporary change in order to mitigate a transient risk. For example, emer-gence of VS in the southwestern United States every few years poses a risk to equine hospitals in the area as admission of a case to the general patient population could result in quarantine of the facility. In this situation, a temporary alteration in bio-security protocols, such as requiring certificates of veterinary inspection or visual inspection prior to entry into the facility, can aid in risk mitigation. Cleaning effectiveness can be moni-tored in many ways, including visual inspection (although a poor indicator of microbiologic cleanliness because a visually clean surface can still harbor pathogens92,93) and environmental cultures once stalls have been cleaned. Increased environmental contamination may indicate a lack of protocol compliance or failure of existing protocols to mitigate the pathogen of interest. Early detection will allow corrective measures to be imple-mented prior to the occurrence of increased nosocomial infec-tions. Monitoring and reporting of environmental contamination

Figure 62-2 Directed mist disinfection using Virkon with a solo backpack mister during annual “bug out” at CSU large animal hospital.


Specific Aspects of Biosecurity

Application of the concepts of biosecurity and biocontainment is important not only in veterinary hospitals but also for ambu-latory practices, equine breeding facilities, training and boarding facilities, and other facilities that house horse populations such as racetracks or those hosting equine events.

Summary of Biosecurity in Equine Veterinary Hospitals

In a veterinary clinic, large numbers of animals, with potentially enhanced susceptibility to infection, are concentrated in a small area, thus increasing the risk of transmission of pathogens from one animal to another, particularly if animals with infectious disease are housed in proximity to animals with increased sus-ceptibility to infection such as immune-compromised patients or neonatal foals. In addition, intensive management or care of patients increases the possibility of exposure to pathogens because of frequent contact between medical personnel and a number of sick equine patients. Design of the facility can impact the ability to control spread of pathogens. Specifically, factors, such as ability to segregate patients by risk level, type of sur-faces, airflow, and air-exchange rate, can influence the success of implemented biosecurity procedures.95 These factors should therefore be taken into consideration when designing equine hospital facilities.

It is important to recognize that nosocomial infections are an inherent risk of hospitalization. This fact should be com-municated clearly to clients. At the CSU-VTH, information about nosocomial infection is part of the admission form that is signed by clients when their horse is admitted to the clinic. The amount of effort aimed at preventing nosocomial disease in an equine clinic depends on specific circumstances such as size of the operation, type of cases managed, type of clientele, financial resources available for this purpose, prevalence of various infectious diseases in the region and risk aversion as perceived by clients and practice management. For example, a two-veterinarian clinic may not need and probably will not be able to justify as extensive a biosecurity program as would be appropriate for a large referral hospital. In general, clients who are highly educated about their horses and willing to pay for advanced medical care are likely to expect high-quality care in all aspects of patient management and would choose a provider who fulfills these criteria. This includes more comprehensive infection control efforts. As mentioned earlier, because nosoco-mial infections are an inherent risk of hospitalization, high quality care cannot be achieved without efforts to prevent these infections. Facilities with a large patient load likely have a larger number of personnel and a larger facility to manage, therefore a written protocol is indicated to allow for uniformity in pro-cedures and to ensure all personnel are informed about the protocols. There are two comprehensive biosecurity programs for VTHs at Colorado State University and the University of California-Davis, which have recently been published.6,95

Biosecurity in Equine Ambulatory Practice

The equine ambulatory practitioner moves between horses that are managed as separate groups such as those owned or trained by different individuals at a single property (i.e., boarding facil-ity) or at equine events (i.e., racetrack). They also move between different facilities, such as the veterinary hospital and a farm; between farms; and between farms and equine events such as shows or other competitions. These movements could result in the transfer of pathogens between groups of horses at the same facility or between different facilities if precautions to avoid

environment near where patients are managed or samples are processed is not an uncommon finding.96 Environmental sur-veillance can be more efficient than monitoring every patient and can identify important reservoirs for exposure. For example, if individual patient Salmonella fecal cultures are not feasible, periodic monitoring of the environment can provide a less expensive alternative. The detection methods used for environ-mental testing must be appropriately validated and optimized. Focusing efforts on high-traffic areas, such as examination areas and alleyways, or on identification of an environmentally per-sistent pathogen (e.g., Salmonella) can be used to monitor the overall efficacy of the biosecurity program and identify possible sources of infectious agents.

Incorporating environmental surveillance into a biosecurity program requires consideration of sample type, method of sample collection, detection method, laboratory selection, and available resources (both financial and personnel). Environmen-tal samples can be collected using multiple methods, including electrostatic wipes or sterile sponges that are cultured for spe-cific microorganism96,97 or contact plates (e.g., Rodac plates) to enumerate nonspecific bacterial growth.98-100 Identification of specific microorganisms relies on the services of a qualified laboratory, whereas nonspecific bacterial counts can be per-formed with limited training of personnel and with a minimal cost.

The type of sample collection device used for testing the environment should be considered as the various options likely will have different sensitivities. For example, in a recent study, electrostatic wipes were a more sensitive collection method compared to sterile sponges for detection of Salmonella enterica in a large animal veterinary hospital environment.97 These dif-ferences can be attributed to both the collection method (the device used and the size of the surface area sampled), as well as the culture method. In general, sampling a larger surface area will not only provide a more representative sample but will likely be a more sensitive method for organism detection. To gain meaningful information, environmental testing should be performed regularly to establish a baseline level of environmen-tal bacterial contamination to which future findings can be compared. In this way, potential environmental reservoirs of microorganisms can be detected and cleaning effectiveness can be continually monitored.

Use of Outdoor Exercise Areas at Equine Hospitals

Although pasture or open paddocks in many ways may be optimal housing environments for equine patients, they are impossible to thoroughly decontaminate. Therefore the use of pasture or paddock should be reserved for horses without suspect or confirmed infectious disease. If it is preferred that a patient with a suspected or confirmed infectious disease have exercise, then they may be exercised by being led in hand on cleanable surfaces. If these surfaces become soiled they must be immediately cleaned and disinfected. If the use of a pasture or paddock is unavoidable, methods for “cleaning” include remov-ing all feces and resting the pasture, allowing sufficient time for infectious agents to die-off before the introduction of other horses to the pasture or paddock.70 The amount of time needed will vary, depending on several factors, including the pathogen, type of pasture or paddock, and climate. The survival time of Streptococcus equi subsp. equi on wood under laboratory condi-tions was reported to be 63 days at 2° C (35.6° F) and 48 days at 20° C (68° F) with a measurable decline in bacterial count occurring after 7 days.101 Alternatively, the dirt in the paddock can be removed and replaced after use by an infectious disease case. If the goal is to allow horses to graze, there are other options for grazing infectious disease cases such as cultivating raised grass beds.


practice vehicle. No sharing of equipment between groups of horses should occur unless sanitized, and there should be no reuse of needles and syringes. Some clients may ask practitio-ners to implement even more stringent procedures for everyday practice such as using outer clothing and footwear dedicated to their facility. The practitioner should comply with these requests. Optimally the practitioner should park their practice vehicle away from the horse housing area to avoid moving material from one premises to another on the tires or undercar-riage of the vehicle. The practice vehicle, including the interior footmats, should be washed whenever visibly dirty, prior to going on the next call.

The ambulatory practitioner should be prepared to manage the risk the examination of a horse with contagious disease poses to a subsequent patient’s care. For example, while on a call to do a purchase examination, a call comes in to examine a horse at a neighboring premises that has a fever and swelling of the head and neck area (i.e., a strangles suspect). Having a “biosecurity kit” that the practitioner can carry in the practice vehicle for themselves and an assistant can facilitate safe exami-nation of a suspected or confirmed case of contagious disease and minimize the chances of carrying contamination to other horses.104 A “biosecurity kit” should contain items used for implementing barrier nursing precautions. For example, exami-nation gloves (at least one pair per horse examined), coveralls dedicated to a given animal’s examination or that of a group of animals of equal status, a covering for the upper body that is impervious to secretions (e.g., nasal discharge), durable water resistant footwear covers, and some type of head covering. Once the barrier precautions are removed, a spray container of disin-fectant for the soles of footwear and hand sanitizer or hand soap with a water source is a must.

If a contagious disease is highly likely or confirmed (i.e., a suspected outbreak of infectious disease), then additional mate-rials, such as disinfectants, gloves, footbaths/footmats, caution-ary signs, etc., should be obtained that would allow ongoing efforts at containing the disease to a given horse or farm. Detailed information has been previously published and is available from the American Association of Equine Practitioners (AAEP), including sources and indications for use of biosecurity supplies.103,104

Protection of Resident Horses and Control of Infectious Diseases at Equine Events

Biosecurity programs for equine facilities can have multiple goals, including reducing the risk of pathogen introduction and, if introduced, reducing the spread of pathogens among horses in the facility. The control measures, such as reducing risk of exposure, that were discussed earlier in the section on hospital infection control also relate to the protection of horses on equine operations. In general, horses that comprise the general equine population, analogous to the “community” for human health discussions, are less susceptible to infectious diseases than those in a hospital population because normal horses are not experiencing the stresses and other risk factors that hospi-talized horses encounter. Therefore use of fewer precautions will likely be effective at minimizing infectious disease risk in a population of healthy horses. However, lack of basic biosecu-rity precautions can result in pathogen introduction and subse-quent spread among the general horse population. Outbreaks of equine infectious diseases can have an impact through the cost incurred in the diagnosis and treatment of sick horses, the implications of stopped horse movement to contain an out-break and the lost use and potentially lost lives of affected horses.105

Infection control for horses in the general equine population can be implemented at many different levels. The owner of the

transmission are not implemented. By way of example, consider equine influenza virus. The predominant methods of spread of equine influenza virus, in decreasing order of importance, are movement of live infectious horses, fomites, and aerosols (local spread). Veterinarians likely accept that horse-to-horse contact plays a role in transmission of contagious equine disease agents, however, they also need to accept and thus take actions to reduce the risk that they themselves could result in pathogen transmission. There have been reports that suggest the most likely way that equine influenza virus moved from a quarantine station to the general horse population in Australia was on the clothing or equipment of a groom, veterinarian, farrier, or other person who had contact with an infected horse and subse-quently left the quarantine station without taking biosecurity measures.102

Horses in the community setting (e.g., outside of the veteri-nary hospital) are likely more resistant to developing disease if exposed to pathogens (i.e., we generally believe that a larger pathogen challenge is required to cause disease in normal animals than in patients in a veterinary hospital, although few studies confirm this assumption). In addition, the time between acquiring a pathogen on clothing, footwear, or equipment and contacting other horses likely reduces the transferred pathogen load, especially for those pathogens that are less environmen-tally persistent such as some viruses.103

Although much of the emphasis on biosecurity for equine practices has been related to the control of transmission of pathogens in veterinary hospitals, the ambulatory practitioner is also obligated to take reasonable precautions to reduce the risk they pose when moving between groups of horses, whether at the same facility or different facilities. Based on recent equine disease outbreaks the equine industry is much more aware of biosecurity practices and thus will expect the veterinarian visit-ing their facility to have taken reasonable precautions to avoid spread of contagious equine pathogens. In addition, because of the heightened awareness among the equine industry, there is an opportunity for the veterinary practitioner to serve as a source of information related to biosecurity at equine facilities, including private farms and competition venues. Thus the ambulatory veterinarian has several incentives to understand and implement biosecurity practices for themselves and their client’s horses, including serving as an example to others when it comes to taking precautions to protect the health of their patients.

The ambulatory equine practitioner should develop a list of every day protocols that become routine infection control prac-tices. These protocols should be followed by the practitioner, thus setting an example for those with whom they work; in addition, they should be practiced by their assistants and clients. These procedures should be employed when working with horses that appear healthy at facilities where no active conta-gious disease is occurring. For example, practicing good hand hygiene between groups of horses that are maintained sepa-rately from each other (i.e., managed by different owners or trainers or residing on different facilities) should be a routine practice. If hands are soiled (e.g., blood, nasal secretions, feces, placental fluid, etc), they should be washed with soap and water as described in the previous section of this chapter. If hands are not grossly soiled and soap and water are unavailable, then use of an alcohol-based hand sanitizer is indicated. Hand hygiene should be performed before touching door handles or the steer-ing wheel of the practice vehicle, as well as before touching objects such as a cell phone or pager. Clean outerwear dedicated to the practice of veterinary care should be worn each day. If the veterinarian’s or their assistant’s outerwear becomes soiled while providing veterinary care, a change of attire is indicated. Footwear should be cleaned with soap and water if there is fecal or soiled bedding present on the soles prior to entering the


approximately 10 minutes to complete, offers equine owners and farm managers the opportunity to assess their risk, and provides educational information related to control of equine infectious diseases. The Equine Biosecurity Principles and Best Practices Guide was developed by the Alberta Veterinary Medical Association and the Alberta Equestrian Federation as a way to interactively educate horse owners while encouraging discussions with veterinarians regarding biosecurity on their farms.110 A Horse Venue Biosecurity Workbook has been devel-oped, based on the equine influenza outbreak that occurred in Australia in 2007, by Animal Health Australia in conjunction with equine industry groups, including the Australian Horse Industry Council.111 This workbook is a self-assessment guide for all horse venues, including race courses, show grounds, pony clubs, and boarding facilities, and it provides a way for managers to assess risk and offers options for managing identified risks. A Biosecurity Toolkit for Equine Events has also been developed by the California Department of Food and Agriculture.112 This toolkit consists of sections focusing on options for preventing the introduction of pathogens to an event, an infection control plan, and options for heightened control efforts should an out-break of a contagious equine disease occur related to an equine event. The recent (2011) multistate EHV-1 outbreak that was traced to horses that attended a large western performance event in Ogden, UT, highlights the potential for equine disease to be transmitted among horses attending competitions or other sites where horses commingle and provides the impetus for facility and event managers to incorporate infection control strategies into facility management and event planning. Table 62-2 provides a list of equine biosecurity resources and Web sites.

The adoption of biosecurity practices on an equine operation is a balance of perceived benefit versus the cost/impact of implementation. The benefits of a biosecurity program can be hard to realize because it is difficult to measure the cost of an outbreak averted. Specific biosecurity plans need to be tailored to the facility or venue based on potential risks for infectious disease entry and spread, risk aversion of the decision makers, control options available, and the available support both finan-cial and for adherence to the biosecurity program.

Equine Owners

Protection of Resident HorsesIn general, horses residing at their home facilities (e.g., horse farms, stables, stud farms, and similar facilities) are typically healthy. As such, a biosecurity program for these facilities tends to focus primarily on preventing the entry of an infectious agent onto the premises and secondarily on controlling the spread of an infectious agent should it enter the establishment. To some degree, all of the control measures previously discussed can be implemented on any equine facility. However, because the general equine population is less likely to be susceptible to common infectious agents, fewer biosecurity precautions will likely be needed to effectively keep this population healthy. Nonetheless, lack of minimum biosecurity practices can lead to the introduction of a new disease agent to a susceptible population, sometimes with serious emotional and financial consequences.42

In general, all resident horses should be vaccinated on a regular basis. The type of vaccines and frequency of administra-tion should be determined by an attending veterinarian based on published evidence of efficacy, knowledge of local disease risks, and consideration of factors such as geographic region, size of the facility, extent of movement of people and horses onto and off the operation, and the age of the resident equine popu-lation. Vaccination principles with specific recommendations related to the core and risk based vaccine recommendations

horse could institute control measures based on the risk their horse is likely to incur, taking into account its use, signalment, and other aspects of its management. For example, a horse ridden alone on trail rides has a different level of risk than a horse attending a group event where the health status of horses with which it can come into contact is unknown. An equine facility manager, such as the manager of a boarding facility, could implement infection control practices that are applied to all horses residing at that facility. Finally, event organizers responsible for shows or other venues where horses come together on a temporary basis to compete or perform could have biosecurity requirements and response plans for disease outbreaks to mitigate the risk of infectious diseases occurring among horses at the event. Each of these decision makers needs to consider the risks the horses they oversee face and how best to manage that risk based on their risk-aversion level.

In general, considerations should be given to the develop-ment of a vaccination and parasite control program, require-ments for horses entering a facility or property (both returning resident horses and nonresident horses), isolation of new arrivals and returning resident horses (e.g., from a show or event), monitoring of horses for infectious disease (e.g., taking daily rectal temperatures of resident horses), infection control strate-gies to be used by those who work with horses (e.g., dedicated attire, working from low risk to high risk), and the development of a response plan should a suspected or confirmed contagious disease be identified. For diseases that are reportable to state or federal animal health officials, the response to disease detection will be regulated by animal health officials.

Various recommendations have been made related to the use of one or more infection control practices on equine operations. In general, these practices include reducing the risk of exposure or optimizing resistance if an animal is exposed. For example, the implementation of vaccination on a population basis, having entry requirements for visitors and nonresident horses, monitor-ing for signs of infectious disease, and pursuing a diagnosis if disease is detected. If disease is detected, the initial response may be to consider it a contagious disease risk. This response can be further refined based on diagnostic testing and detection of subsequent cases, thereby tailoring the response to the detected problem.106

A study based on the National Animal Health Monitoring Survey (NAHMS) Equine 2005 data found that 78.5% of par-ticipating U.S. equine operations with greater than or equal to five resident horses had some risk of exposure to nonresident horses in the previous year.107 As the size of the operation increased so too did the risk for exposure to nonresident horses, as well as the likelihood for implementing biosecurity measures. This study suggested that the most at-risk equine facilities defined as operations with resident horses having contact with nonresident horses were more likely to implement biosecurity practices aimed at multiple aspects of infection control (e.g., vaccination, entry requirements, and response to detected disease).107 A recent survey of select Colorado equine boarding facilities found that many facilities had the opportunity to implement additional infectious disease control measures with 22.6% of respondents deemed to have less than adequate bio-security at their facility.108 Among respondents, 6.6% regularly employed isolation of resident equids returning from travel and among facilities that regularly receive new equids, only 50% reported requiring isolation of these equids from resident horses.108

There have been recent additions to the available resources on equine biosecurity for equine owners and facility managers. An Equine Biosecurity Risk Calculator has been developed as an educational resource by Equine Guelph (University of Guelph) in partnership with CSU, sponsored by the AAEP Foundation and Vétoquinol Canada, Inc.109 This risk calculator survey takes


horses are similar to those discussed for resident horses, with day-to-day hygiene and use of efficacious vaccines playing major roles in maintaining health.

Although it is often difficult to restrict traffic around travel-ing horses (e.g., at sale barns or competitions), it is possible to limit direct contact to only essential personnel. It is also possible to provide stall-side hand sanitizers and options for footwear sanitation to further minimize trafficking of pathogens. Stalls at equine events can be thoroughly cleaned and disinfected between uses either by the event coordinators or by the par-ticipants, although the efficacy of these actions may be hindered by porous construction materials (e.g., wood) and dirt stall floors. In addition, good ventilation and temperature control can help reduce stress on the respiratory tract of horses and reduce circulation of pathogens. Owners or trainers of travelling horses should involve their veterinarian in developing a plan for infec-tion control that includes vaccination, as well as ways to reduce exposure risk and monitor for disease occurrence.

Conclusions

Biosecurity and infection control are important aspects of the day-to-day operation of any equine facility and are especially important for equine hospitals. A successful infection control program requires the commitment and participation of all per-sonnel. It is essential that the people in decision-making roles, such as clinicians (in the hospital) and owners, trainers, or man-agers (in an equine facility), educate personnel about biosecu-rity and observe compliance with infection control measures. Leadership by example is the best way to ensure compliance of all personnel. Additionally, educational efforts should be undertaken to make sure all personnel understand the impor-tance of biosecurity and their role in maintaining the facility as a safe place for horses and their human caregivers.

The complete reference list is available online at www.expert-consult.com.

have been previously published by the AVMA and AAEP.113,114 All new arrivals, including resident horses returning from com-petitions, breeding facilities, or sales, should be quarantined for a period that exceeds the maximum incubation period for the disease of concern. According to a survey conducted by the U.S. Department of Agriculture Veterinary Services in 2005, among a representative sample of equine operations in 28 states, approximately one-third of equine operations that added resident equids routinely isolated new arrivals. The majority of those that isolated newly arrived horses used a separation period of more than 2 weeks, with an average length of quarantine of 28.5 days.115 Any traffic to and from equine facilities should be minimized or controlled. For example, any commercial vehicles that are likely to have visited other farms can be restricted from entering horse stabling areas. Visitors can be asked to wear clean clothing, wash their hands before contact with the horses on the premises, or step on a disinfectant footmat before entering the stabling area. It may be advisable to ask the medical history for all horses coming onto the opera-tion and specifically inquire about recent episodes of respiratory infection or diarrhea. Similarly, all visiting horses on arrival should be inspected for clinical signs of infectious disease, such as diarrhea or nasal discharge, denying facility access to animals showing such signs. It may also be helpful to require all visiting horses to be from premises with active parasite control pro-grams and be vaccinated against specified pathogens. Premises owners could require documentation of an active parasite control and vaccination program, as well as require testing of new arrivals for diseases of concern.

Protection of Traveling HorsesAn equine owner should be concerned with the possible expo-sure of horses to pathogens at sales, competitions, training stables, breeding facilities, or anywhere horses congregate from multiple different sources. In addition to difficulties in control-ling exposure to possible pathogens in these situations, traveling horses may have a compromised immune system and therefore may be more likely to develop clinical disease when exposed to common pathogens.116 Principles of biosecurity for these

Table 62-2 Biosecurity Resources

Resource Web site

AAEP Vaccination Guidelines114 www.aaep.org/vaccination_guidelines.htmBiosecurity Tool Kit for Equine Events112 www.cdfa.ca.gov/ahfss/Animal_Health/Equine_Biosecurity.htmlEquine Biosecurity Principles and Best Practices110 www.albertaequestrian.com/BiosecurityEquine Biosecurity Risk Calculator (Equine Guelph)109 www.equineguelph.ca/Tools/biosecurity_2011.phpEquine infectious disease outbreak: AAEP Control Guidelines103 www.aaep.org/control_guidelines_nonmember.htmHand hygiene in health care settings: Hand hygiene basics57 www.cdc.gov/handhygiene/Basics.htmlHand hygiene in health care settings: Guidelines58 www.cdc.gov/handhygiene/Guidelines.htmlHorse Venue Biosecurity Workbook (Animal Health Australia)111 www.horsecouncil.org.au/_Upload/Files/Horse%20Venue%20Biosecurity%20

Workbook.pdfBiosecurity supplies* www.gemplers.com (Disinfection Mat, Footbath Mat, Virkon S†)

www.eNasco.com (Entrance Disinfection Mat, face shields, protective eyewear)www.qcsupply.com (Knot-a-Boot‡)

*Not an endorsement; provided to allow readers to quickly find resources in an emergency. The authors’ encourage readers to develop their own product preferences and suppliers.†Virkon S, Antec International, Sudbury, Suffolk, United Kingdom.‡Knot-a-Boot, Continental Plastic Corp, Delavan, WI.

http://www.aaep.org/vaccination_guidelines.htm

http://www.cdfa.ca.gov/ahfss/Animal_Health/Equine_Biosecurity.html

http://www.albertaequestrian.com/Biosecurity

http://www.equineguelph.ca/Tools/biosecurity_2011.php

http://www.aaep.org/control_guidelines_nonmember.htm

http://www.cdc.gov/handhygiene/Basics.html

http://www.cdc.gov/handhygiene/Guidelines.html

http://www.horsecouncil.org.au/_Upload/Files/Horse%20Venue%20Biosecurity%20Workbook.pdf


http://www.gemplers.com

http://www.expertconsult.com

http://www.expertconsult.com

References1. Blystone M: Rinderpest: one virus’s impact on veterinary

history. Vet Herit 24(1):8–12, 2001.2. Cork DP, Maxwell PJ, Yeo CJ: Remembering Semmelweis:

hand hygiene and its importance on today’s clinical prac-tice. Am Surg 77(1):123–125, 2011.

3. Smith BP: Evolution of equine infection control programs. Vet Clin North Am Equine Pract 20(3):521–530, v, 2004.

4. Nightingale F: Notes on Hospitals, 3 ed. London, 1863, Longman, Green, Longman, Roberts and Green.

5. Haley RW, Culver DH, White JW, et al: The efficacy of infection surveillance and control programs in preventing nosocomial infections in US hospitals. Am J Epidemiol 121(2):182–205, 1985.

6. Morley PS: Biosecurity of veterinary practices. Vet Clin North Am Food Anim Pract 18(1):133–155, 2002.

7. Who we are: Veterinarian’s oath, 2012. Available at http://www.avma.org/about_avma/whoweare/oath.asp. Accessed January 1, 2012.

8. Morley PS, Anderson MEC, Burgess BA, et al: Report of the third Havemeyer workshop on infection control in equine populations. Eq Vet J 45(2):131–136, 2013.

9. Grant S, Olsen CW: Preventing zoonotic diseases in immunocompromised persons: the role of physicians and veterinarians. Emerg Infect Dis 5(1):159–163, 1999.

10. Gauthier JL, Richardson DJ: Knowledge and attitudes about zoonotic helminths: a survey of Connecticut pedia-tricians and veterinarians. Compend Contin Educ Pract Vet 24(5(A)):4–9, 2002.

11. Babcock S, Marsh AE, Lin J, et al: Legal implications of zoonoses for clinical veterinarians. J Am Vet Med Assoc 233(10):1556–1562, 2008.

12. Morey RS: The General Duty Clause of the Occupational Safety and Health Act of 1970. Harvard Law Review 86(6):988–1005, 1973.

13. Lipton BA, Hopkins SG, Koehler JE, et al: A survey of veterinarian involvement in zoonotic disease prevention practices. J Am Vet Med Assoc 233(8):1242–1249, 2008.

14. Wright JG, Jung S, Holman RC, et al: Infection control practices and zoonotic disease risks among veterinarians in the United States. J Am Vet Med Assoc 232(12):1863–1872, 2008.

15. Murphy CP, Reid-Smith RJ, Weese JS, et al: Evaluation of specific infection control practices used by companion animal veterinarians in community veterinary practices in southern Ontario. Zoonoses Public Health 57(6):429–438, 2010.

16. State Board of Veterinary Medicine 4 CCR 727–721 Rules and Regulations. Available at http://www.dora.state.co. us/Veterinarians/forms/Rules.pdf. Accessed February 24, 2012.

17. Benedict KM, Morley PS, Van Metre DC: Characteristics of biosecurity and infection control programs at veterinary teaching hospitals. J Am Vet Med Assoc, 233(5):767–773, 2008.

18. Firestone SM, Schemann KA, Toribio JA, et al: A case-control study of risk factors for equine influenza spread onto horse premises during the 2007 epidemic in Austra-lia. Prev Vet Med 100(1):53–63, 2011.

19. Taylor LH, Latham SM, Woolhouse ME: Risk factors for human disease emergence. Philos Trans R Soc Lond B Biol Sci 356(1411):983–989, 2001.

20. Baker WS, Gray GC: A review of published reports regard-ing zoonotic pathogen infection in veterinarians. J Am Vet Med Assoc 234(10):1271–1278, 2009.

21. Bender JB, Shulman SA: Reports of zoonotic disease outbreaks associated with animal exhibits and availability of recommendations for preventing zoonotic disease

transmission from animals to people in such settings. J Am Vet Med Assoc 224(7):1105–1109, 2004.

22. Bender JB, Tsukayama DT: Horses and the risk of zoonotic infections. Vet Clin North Am Equine Pract 20(3):643–653, 2004.

23. Arya B, Hussian S, Hariharan S: Rhodococcus equi pneu-monia in a renal transplant patient: a case report and review of literature. Clin Transplant 18(6):748–752, 2004.

24. Weese JS, DaCosta T, Button L, et al: Isolation of methicillin-resistant Staphylococcus aureus from the envi-ronment in a veterinary teaching hospital. J Vet Intern Med 18(4):468–470, 2004.

25. Weese JS: Methicillin-resistant Staphylococcus aureus in horses and horse personnel. Vet Clin North Am Equine Pract 20(3):601–613, 2004.

26. Weaver SC, Ferro C, Barrera R, et al: Venezuelan equine encephalitis. Annu Rev Entomol 49:141–174, 2004.

27. Blanton JD, Hanlon CA, Rupprecht CE: Rabies surveil-lance in the United States during 2006. J Am Vet Med Assoc 231(4):540–556, 2007.

28. Hamir AN, Moser G, Rupprecht CE: A five year (1985–1989) retrospective study of equine neurological diseases with special reference to rabies. J Comp Pathol 106(4):411–421, 1992.

29. Takatori K, Ichijo S: Human dermatophytosis caused by Trichophyton equinum. Mycopathologia 90(1):15–19, 1985.

30. Huovinen S, Tunnela E, Huovinen P, et al: Human ony-chomycosis caused by Trichophyton equinum transmitted from a racehorse. Br J Dermatol 138(6):1082–1084, 1998.

31. Maslen M, Thompson PG: Human infections due to Trichophyton equinum var. autotrophicum in Victoria. Aus-tralas J Dermatol 25(1):29–32, 1984.

32. Kane J, Padhye AA, Ajello L: Microsporum equinum in North America. J Clin Microbiol 16(5):943–947, 1982.

33. Minces LR, Brown PJ, Veldkamp PJ: Human meningitis from Streptococcus equi subsp. zooepidemicus acquired as zoonoses. Epidemiol Infect 139(3):406–410, 2011.

34. Barclay AJ, Paton DJ: Hendra (equine morbillivirus). Vet J 160(3):169–176, 2000.

35. Playford EG, McCall B, Smith G, et al: Human Hendra virus encephalitis associated with equine outbreak, Aus-tralia, 2008. Emerg Infect Dis 16(2):219–223, 2010.

36. Westbury H: Hendra virus: a highly lethal zoonotic agent. Vet J 160(3):165–166, 2000.

37. Hooper PT, Williamson MM: Hendra and Nipah virus infections. Vet Clin North Am Equine Pract 16(3):597–603, xi, 2000.

38. Another human case of equine Morbillivirus disease in Australia. Emerg Infect Dis 2(1):71–72, 1996.

39. Tillotson K, Savage CJ, Salman MD, et al: Outbreak of Salmonella infantis infection in a large animal veterinary teaching hospital. J Am Vet Med Assoc 211(12):1554–1557, 1997.

40. Goehring LS, Landolt GA, Morley PS: Detection and management of an outbreak of equine herpesvirus type 1 infection and associated neurological disease in a veteri-nary teaching hospital. J Vet Intern Med 24(5):1176–1183, 2010.

41. Burgess BA, Tokateloff N, Manning S, et al: Nasal shedding of equine herpesvirus-1 from horses in an outbreak of equine herpes myeloencephalopathy in western Canada. J Vet Intern Med 26(2):384–392, 2012.

42. Dallap Schaer BL, Aceto H, Rankin SC: Outbreak of salmonellosis caused by Salmonella enterica serovar Newport MDR-AmpC in a large animal veterinary teach-ing hospital. J Vet Intern Med 24(5):1138–1146, 2010.

543.e1Chapter 62 Biosecurity and Control of Infectious Disease Outbreaks

http://refhub.elsevier.com/B978-1-4557-0891-8.00062-2/sr0010
































































































































http://www.avma.org/about_avma/whoweare/oath.asp

http://www.avma.org/about_avma/whoweare/oath.asp

http://www.dora.state.co.us/Veterinarians/forms/Rules.pdf

http://www.dora.state.co.us/Veterinarians/forms/Rules.pdf

43. Traub-Dargatz JL, Dargatz DA: Antibacterial drug resis-tance and equine practice. Equine Vet Educ 21(1):49–56, 2009.

44. Besser TE, Hancock D, Davis MA: The veterinarian’s role in controlling the emergence and dissemination of drug-resistant bacteria. J Vet Med Educ 30(2):136–139, 2003.

45. Warren DK, Fraser VJ: Infection control measures to limit antimicrobial resistance. Crit Care Med 29(4 suppl):N128-N134, 2001.

46. Levy SB, Marshall B: Antibacterial resistance worldwide: causes, challenges and responses. Nat Med 10(12 suppl): S122-S129, 2004.

47. Sidhu MS, Heir E, Leegaard T, et al: Frequency of disin-fectant resistance genes and genetic linkage with beta-lactamase transposon Tn552 among clinical staphylococci. Antimicrob Agents Chemother 46(9):2797–2803, 2002.

48. Rajamohan G, Srinivasan VB, Gebreyes WA: Molecular and functional characterization of a novel efflux pump, AmvA, mediating antimicrobial and disinfectant resis-tance in Acinetobacter baumannii. J Antimicrob Che-mother 65(9):1919–1925, 2010.

49. Burke JP: Infection control—a problem for patient safety. N Engl J Med 348(7):651–656, 2003.

50. Johnson JA: Nosocomial infections. Vet Clin North Am Small Anim Pract 32(5):1101–1126, 2002.

51. Dargatz DA, Traub-Dargatz JL: Multidrug-resistant Salmonella and nosocomial infections. Vet Clin North Am Equine Pract 20(3):587–600, 2004.

52. Morley PS, Apley MD, Besser TE, et al: Antimicrobial drug use in veterinary medicine. J Vet Inter Med 19(4):617–629, 2005.

53. AVMA Policy: Judicious therapeutic use of antimicrobials. 2008 [cited 2012 March 1]; available from: http://www. avma.org/issues/policy/jtua.asp.

54. Haley RW: The scientific basis for using surveillance and risk factor data to reduce nosocomial infection rates. J Hosp Infect 30(Suppl):3–14, 1995.

55. Scheftel JM, Elchos BL, Cherry B, et al: Compendium of veterinary standard precautions for zoonotic disease pre-vention in veterinary personnel: National Association of State Public Health Veterinarians Veterinary Infection Control Committee 2010. J Am Vet Med Assoc 237(12): 1403–1422, 2010.

56. Baskerville A: Mechanisms of infection in the respiratory tract. N Z Vet J 29(12):235–238, 1981.

57. Guidelines for hand hygiene in healthcare settings. J Am Coll Surg 198(1):121–127, 2004.

58. Hand Hygiene in Healthcare Settings: Guidelines, 2011. Available at http://www.cdc.gov/handhygiene/Guidelines. html. Accessed March 1, 2012.

59. Hand hygiene in healthcare settings: Hand hygiene basics. 2011 [cited 2012 February 26]; available from: http://www.cdc.gov/handhygiene/Basics.html.

60. Larson E: Hygiene of the skin: when is clean too clean? Emerg Infect Dis 7(2):225–230, 2001.

61. Boyce JM, Pittet D: Guideline for Hand Hygiene in Health-Care Settings. Recommendations of the Health-care Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. Society for Healthcare Epidemiology of America/Association for Professionals in Infection Control/Infectious Diseases Society of America. MMWR 51(RR-16):1–45, 2002.

62. Traub-Dargatz JL, Weese JS, Rousseau JD, et al: Pilot study to evaluate 3 hygiene protocols on the reduction of bacterial load on the hands of veterinary staff performing routine equine physical examinations. Can Vet J 47(7): 671–676, 2006.

63. Boyce JM: Antiseptic technology: access, affordability, and acceptance. Emerg Infect Dis 7(2):231–233, 2001.

64. Goldmann DA: The role of barrier precautions in infection control. J Hosp Infect 18 (Suppl A):515–523, 1991.

65. Weese JS: Barrier precautions, isolation protocols, and per-sonal hygiene in veterinary hospitals. Vet Clin North Am Equine Pract 20(3):543–559, 2004.

66. Olsen RJ, Lynch P, Coyle MB, et al: Examination gloves as barriers to hand contamination in clinical practice. JAMA 270(3):350–353, 1993.

67. Morley PS, et al: Evaluation of the efficacy of disinfectant footbaths as used in veterinary hospitals. J Am Vet Med Assoc 226(12):2053–2058, 2005.

68. Dunowska M, Morley PS, Patterson G, et al: Evaluation of the efficacy of a peroxygen disinfectant-filled footmat for reduction of bacterial load on footwear in a large animal hospital setting. J Am Vet Med Assoc 228(12):1935–1939, 2006.

69. Miller K, et al: Durability of disposable overboots under simulated field conditions. In 54th Annual Convention of the American Association of Equine Practitioners, 2008, San Diego.

70. Dwyer RM: Environmental disinfection to control equine infectious diseases. Vet Clin North Am Equine Pract 20(3):531–542, 2004.

71. Hall-Stoodley L, Costerton JW, Stoodley P: Bacterial bio-films: from the natural environment to infectious diseases. Nat Rev Microbiol 2(2):95–108, 2004.

72. Stewart PS, Costerton JW: Antibiotic resistance of bacteria in biofilms. Lancet 358(9276):135–138, 2001.

73. Joseph B, Otta SK, Karunasagar I: Biofilm formation by Salmonella spp. on food contact surfaces and their sensitiv-ity to sanitizers. Int J Food Microbiol 64(3):367–372, 2001.

74. Dwyer RM: Disinfecting equine facilities. Rev Sci Tech 14(2):403–418, 1995.

75. Dunowska M, Morley PS, Hyatt DR: The effect of Virkon S fogging on survival of Salmonella enterica and Staphylococcus aureus on surfaces in a veterinary teaching hospital. Vet Microbiol 105(3–4):281–289, 2005.

76. Patterson G, Morley PS, Blehm KD, et al: Efficacy of directed misting application of a peroxygen disinfectant for environmental decontamination of a veterinary hospi-tal. J Am Vet Med Assoc 227(4):597–602, 2005.

77. Brody MD: AVMA guide for veterinary medical waste management. J Am Vet Med Assoc 195(4):440–452, 1989.

78. AVMA Policy: Veterinary Medical Waste. 2008 Available at http://www.avma.org/issues/policy/veterinary_wastes. asp. Accessed March 13, 2012.

79. Guardabassi L, Schwarz S, Lloyd DH: Pet animals as res-ervoirs of antimicrobial-resistant bacteria. J Antimicrob Chemother 54(2):321–332, 2004.

80. Wall PG, et al: Chronic carriage of multidrug resistant Salmonella typhimurium in a cat. J Small Anim Pract 36(6):279–281, 1995.

81. Tauni MA, Osterlund A: Outbreak of Salmonella typhimurium in cats and humans associated with infec-tion in wild birds. J Small Anim Pract 41(8):339–341, 2000.

82. Veling J, Wilpshaar H, Frankena K, et al: Risk factors for clinical Salmonella enterica subsp. enterica serovar Typhimurium infection on Dutch dairy farms. Prev Vet Med 54(2):157–168, 2002.

83. Elsheikha HM, Murphy AJ, Mansfield LS: Prevalence of and risk factors associated with the presence of Sarcocystis neurona sporocysts in opossum (Didelphis virginiana)

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from Michigan: a retrospective study. Vet Parasitol 125 (3–4):277–286, 2004.

84. Schuler LA, Khaitsa ML, Dyer NW, et al: Evaluation of an outbreak of West Nile virus infection in horses: 569 cases (2002). J Am Vet Med Assoc 225(7):1084–1089, 2004.

85. Romi R, Pontuale G, CIufolini MG, et al: Potential vectors of West Nile virus following an equine disease outbreak in Italy. Med Vet Entomol 18(1):14–19, 2004.

86. Sellon DC: Equine infectious anemia. Vet Clin North Am Equine Pract 9(2):321–336, 1993.

87. Morley PS, Strohmeyer RA, Tankson JD, et al: Evaluation of the association between feeding raw meat and Salmonella enterica infections at a Greyhound breeding facility. J Am Vet Med Assoc 228(10):1524–1532, 2006.

88. Wales AD, Carrique-Mas JJ, Rankin M, et al: Review of the carriage of zoonotic bacteria by arthropods, with special reference to Salmonella in mites, flies and litter beetles. Zoonoses Public Health 57(5):299–314, 2010.

89. Mian LS, Maag H, Tacal JV: Isolation of Salmonella from muscoid flies at commercial animal establishments in San Bernardino County, CA. J Vector Ecol 27(1):82–85, 2002.

90. McCluskey BJ: Biosecurity for arthropod-borne diseases. Vet Clin North Am Food Anim Pract 18(1):99–114, 2002.

91. Hurd HS, McCluskey BJ, Mumford EL: Management factors affecting the risk for vesicular stomatitis in live-stock operations in the western United States. J Am Vet Med Assoc 215(9):1263–1268, 1999.

92. Griffith CJ, Cooper RA, Gilmore J, et al: An evaluation of hospital cleaning regimes and standards. J Hosp Infect 45(1):19–28, 2000.

93. Cooper RA, Griffith CJ, Malik RE, et al: Monitoring the effectiveness of cleaning in four British hospitals. Am J Infect Control 35(5):338–341, 2007.

94. Morley PS: Surveillance for nosocomial infections in vet-erinary hospitals. Vet Clin North Am Equine Pract 20(3):561–576, vi-vii, 2004.

95. Smith BP, House JK, Magdesian KG, et al: Principles of an infectious disease control program for preventing noso-comial gastrointestinal and respiratory tract diseases in large animal veterinary hospitals. J Am Vet Med Assoc 225(8):1186–1195, 2004.

96. Burgess BA, Morley PS, Hyatt DR: Environmental surveil-lance for Salmonella enterica in a veterinary teaching hos-pital. J Am Vet Med Assoc 225(9):1344–1348, 2004.

97. Ruple-Czerniak A, Burgess BA, Morley PS: Isolation of Salmonella enterica from the environment in a large animal hospital using electrostatic and sterile sponge collection devices, Proceedings of the 92nd Annual Conference of Research Workers in Animal Diseases, Chicago, IL, 2011, abstract 27.

98. Hacek DM, Trick WE, Collins SM, et al: Comparison of the Rodac imprint method to selective enrichment broth for recovery of vancomycin-resistant enterococci and drug-resistant Enterobacteriaceae from environmental sur-faces. J Clin Microbiol 38(12):4646–4648, 2000.

99. Lemmen SW, Häfner H, Reinert RR, et al: Comparison of two sampling methods for the detection of gram-positive and gram-negative bacteria in the environment: moistened swabs versus Rodac plates. Int J Hyg Environ Health 203(3):245–248, 2001.

100. Stockton KA, Morley PS, Hyatt DR, et al: Evaluation of the effects of footwear hygiene protocols on nonspecific bacterial contamination of floor surfaces in an equine hospital. J Am Vet Med Assoc 228(7):1068–1073, 2006.

101. Sweeney CR, Timoney JF, Newton JR, et al: Streptococcus equi infections in horses: guidelines for treatment, control, and prevention of strangles. J Vet Intern Med 19(1):123–134, 2005.

102. Cullinan I: Equine influenza: the August 2007 outbreak in Australia. Report of the Equine Influenza Inquiry, 2008. Available from http://www.equineinfluenzainquiry.gov.au. Accessed February 28, 2012.

103. Equine infectious disease outbreak: AAEP control guide-lines, 2012. Available from: http://www.aaep.org/control_guidelines_nonmember.htm. Accessed February 28, 2012.

104. Lunn DP, Traub-Dargatz JL: Managing infectious disease outbreaks at events and farms; challenges and the resources for success. in 53rd Annual Convention of the American Association of Equine Practitioners, 2007, Orlando, FL.

105. Equine herpesvirus myeloencephalopathy: Mitigation, expriences, lessons learned, and future needs. 2008 [cited 2012 March 14]; available from: http://www.aphis. usda.gov/vs/nahss/equine/ehv/equine_herpesvirus_nahms_2008report.pdf.

106. Traub-Dargatz JD, Dargatz DA, Morley PS, et al: Infection control strategies for horses in the new millennium. In 47th Annual Convention of the American Association of Equine Practitioners, 2001, San Diego.

107. Traub-Dargatz J, Kopral C, Wagner B: Relationship of bio-security practices with the use of antibiotics for the treat-ment of infectious disease on U.S. equine operations. Prev Vet Med 104(1–2):107–113, 2011.

108. Kirby AT, Traub-Dargatz JL, Hill AE, et al: Development, application, and validation of a survey for infectious disease control practices at equine boarding facilities. J Am Vet Med Assoc 237(10):1166–1172, 2010.

109. Guelph E: Equine Biosecurity Risk Calculator, 2011 [cited 2012 Februrary 29]; available from: http://www. equineguelph.ca/Tools/biosecurity_2011.php.

110. Equine Biosecurity Policies and Best Practices Guide, 2011 [cited 2012 March 19]; available from: http://www.albertaequestrian.com/Biosecurity.

111. Horse Venue Biosecurity Workbook, 2010 [cited 2012 February 29]; available from: http://www.horsecouncil. org.au/_Upload/Files/Horse%20Venue%20Biosecurity %20Workbook.pdf.

112. Flynn K: Biosecurity Toolkit for Equine Events, 2012. Available from http://www.cdfa.ca.gov/ahfss/. Accessed March 1, 2012.

113. AVMA Policy: Vaccination Principles, 2007. Available from http://www.avma.org/issues/policy/vaccination_principles.asp. Accessed March 1, 2012.

114. AAEP Vaccination Guidelines, 2012. Available from: http://www.aaep.org/vaccination_guidelines.htm. Accessed March 1, 2012.

115. Animal Health: NAHMS Equine Studies, 2005. Available from: http://www.aphis.usda.gov/animal_health/nahms/equine/index.shtml. Accessed March 1, 2012.

116. Racklyeft DJ, Raidal S, Love DN: Towards an understand-ing of equine pleuropneumonia: factors relevant for control. Aust Vet J 78(5):334–338, 2000.

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http://www.avma.org/issues/policy/vaccination_principles.asp

http://www.aaep.org/vaccination_guidelines.htm

http://www.aphis.usda.gov/animal_health/nahms/equine/index.shtml

http://www.aphis.usda.gov/animal_health/nahms/equine/index.shtml

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Equine Infectious Diseases || Biosecurity and Control of Infectious Disease Outbreaks