Despite the fact that infectious agents are always present in the environment, under normal conditions, health is maintained. It is well recognized that the development of infectious disease is determined by a complex interaction of many factors surrounding the host, infectious agent, and the environment. The species, age, sex, general health, and immune status, as well as stress level and genetic predispositions of the host are all known to be factors that influence animal health (Greene 2012).
Infectious agents vary in virulence and modes of transmission. In many cases, they persist in the environment because they are resistant to disinfection, and many produce carrier states that contribute to continued environmental contamination or direct exposure of other animals. The amount and duration of exposure to an infectious agent, as well as methods of spread, routes of inoculation, carrier states, and mutation rates will all affect the likelihood that disease will spread in the shelter environment. Disease may be spread by direct contact with infected animals or carriers, via inhalation, ingestion, and contact with feces, urine, other bodily secretions, fomites, or even vectors such as fleas, ticks, flies and mosquitoes. Environmental factors also contribute substantially to disease, including housing density, ease of cleaning/disinfection, extremes or fluctuations of temperature, and air quality, among others. Environmental stressors such as loud or unfamiliar noises, unfamiliar stimuli, and unpredictable events are additional contributors. Thus, no single factor results in disease; rather, disease results from a combination of factors.
The importance of adhering to traditional general principles of infectious disease control must never be overlooked in an animal shelter. These include:
1 Vigilant surveillance and early recognition of disease.
2 Removal of infected animals (through isolation, transfer to foster care or other veterinary or rescue partners with adequate facilities, or euthanasia).
3 Mass vaccination and/or mass treatment.
4 Good husbandry and wellness practices (animals and environment).
5 Continual education and training of personnel.
Ultimately, disease control is best addressed proactively by establishing and implementing wellness protocols. Please see the Introduction in Chapter 1 for more information on the principles of infectious disease control in a shelter.
2.2.4.1 Population Management and Capacity for Care
In the field of shelter medicine, the term population management is used to refer to an active daily process of planning involving ongoing evaluation and efficient response as an organization cares for multiple animals (Newbury and Hurley 2013). Providing efficient evaluation and care of animals is the key to minimizing each animal's length of stay (LOS) in the shelter, and therefore reducing their risk for the development of disease and problem behaviors. When populations are efficiently managed, wellness care is effectively delivered to support the physical and behavioral health of animals and their environment, increasing the animals' resistance to disease as well as their emotional resilience. In order to be effective, population management must take into consideration an organization's ability and resources to provide care.
The maximum daily population in an animal shelter that allows for maintenance of recommended standards of care has been defined by the Association of Shelter Veterinarians' Guidelines for Standards of Care in Animal Shelters (2010) as “capacity for care.” Many factors impact a shelter's capacity for care including the availability of housing, staffing, and all other resources necessary to provide humane care. When sheltering organizations operate without sufficient resources to provide proper animal care, animal health and welfare are compromised. Increases in the prevalence of infectious diseases are common, and likewise, increases in displays of fear, anxiety, stress and frustration‐related behaviors by resident animals can be expected. The delivery of effective population management and operating within an organization's capacity for care are both key requirements for the successful implementation of a shelter wellness program. Please see the Introduction in Chapter 1 for more information about population management.
2.2.4.2 Components of a Shelter Wellness Program
Wellness starts with the prevention of both disease and problem behaviors. Prevention is more time and cost‐efficient than treatment. In addition, it reduces suffering and is kinder to the animals as well as to the staff that must care for them. Table 2.2 contains the recommended components of a wellness protocol for shelter cats and dogs, and Table 2.3 shows the recommended components of a wellness protocol for the shelter environment.
Table 2.2 Recommended components of a wellness protocol for shelter cats and dogs.
| Animal Wellness = Physical Health + Behavioral Health | |
|---|---|
| Physical Health | Behavioral (Emotional) Health |
| History and physical examination | History and behavioral examination/observation |
| Vaccination | Proper housing |
| Parasite control/prevention | Enrichment including:Social companionshipPhysical stimulation/exerciseMental stimulationPositive training |
| Spay‐neuter | |
| Animal Identification (ID)Proper nutrition and physical exerciseGroomingPeriodontal/oral disease preventionIndividual‐specific care | |
| Positive emotional environment |
Table 2.3 Recommended components of a wellness protocol for the shelter environment.
| Environmental Wellness = Physical Environment + Emotional Environment | |
|---|---|
| Physical Environment | Emotional Environment |
| Population densitySegregation of animals and traffic patternsCleaning and sanitationOther facility operations:Heating, ventilation, and air conditioning (HVAC)Noise controlRegular light/dark cyclesFacility maintenance, etc.Staff training | Mitigation of stressors and factors that elicit fear, including noise and unfamiliar stimuliConsistent daily routinesPositive predictable interactions and events |
2.3 The Problem‐Oriented Approach to Shelter Medicine
In animal shelters, it is important to have efficient systems that allow for the assessment of individual animals while affording consideration to the population itself. Indeed, shelter medicine represents a unique blend of both individual patient and population medicine. A useful system for patient evaluation is known as the “problem‐oriented approach,” which is widely accepted as the gold standard for small animal patient care and assessment.
A problem is defined as “any abnormality requiring medical or surgical management or one that interferes with quality of life” (Lorenz 1993). Thus, problems include both physical and behavioral conditions that require management or treatment and/or that affect welfare. In an animal shelter, problems are
