Infectious Disease Management in Animal Shelters. Группа авторов

much information as possible about an animal's emotional state, welfare, and personality. Careful attention must be given to housing and enrichment, and concurrent population management strategies must be employed to minimize LOS and maximize the best outcomes for animals.

      2.6.1 The Role of Stress

      Stress involves outcomes secondary to increased secretion of catecholamines and cortisol. The harmful effects of chronic activation of these hormones have been well described and include adverse metabolic responses that promote dehydration, mental depression, insulin resistance, peptic ulcer formation and increased susceptibility to infection (Greco 1991; Moberg 1985). Chronic stress can also alter metabolism sufficiently to cause weight loss, prevent normal growth, and result in persistent abnormal behavior deleterious to the animal. Stress responses and immunity are also intimately related; stress compromises the immune response, lowering resistance to infection (Griffin 1989). In fact, stress can trigger the shedding of certain viral pathogens, including reactivation of latent viral rhinotracheitis (feline herpesvirus) infections in cats (Gaskell and Povey 1977). In an animal shelter, minimizing stress has the potential to greatly improve animal welfare, decrease infection rates and disease transmission, and enhance adoptability.

A stressor represents any stress‐producing factor or stimulus. Housing cats and dogs in animal shelters presents enormous opportunities for introducing stressors. Stressors may include illness; captivity; transport; crowding; isolation; changes in diet, environmental temperature, light patterns, and/or ventilation; strange smells; noises; other animals; handling and restraint; irregular caregiving schedules; unpredictable daily manipulations; the absence of familiar human contact; and the presence of unfamiliar human contact. In fact, anything unfamiliar to a cat or dog can trigger apprehension and activate the stress response. The severity, chronicity, novelty, predictability, and duration of the stressor, as well as the individual's perception, influence the response to a stressor (McMillan 2002; Moberg 1985). An individual animal's perception of a stressor is influenced by its genetic makeup, personality, and prior socialization and experience.

      If allowed, animals employ coping strategies in order to lessen the negative impacts of a stressor (Carlstead et al. 1993; McMillan 2002). There is marked variability among individuals regarding their ability to cope. Some examples of behavioral coping strategies include hiding, seeking social companionship, and acquiring mental stimulation. Those that are successfully able to cope will suffer less from the physical and mental impacts of stress and will adjust better to life in an animal shelter. That being said, it is rare to find an animal that thrives when housed long term in a shelter.

      When animals are housed in shelters, stress frequently originates from the loss of control over conditions and lack of opportunities for engaging in active behavioral responses that would serve as a means of coping. When stress is perceived as inescapable or uncontrollable, the resulting stress response is most severe (Carlstead et al. 1993; McMillan 2002). This is an extremely important consideration when designing housing and husbandry protocols for cats and dogs in shelters.

      2.6.2 Behavioral Needs of Cats and Dogs

      In addition to basic physical needs (such as proper nutrition and shelter), certain behavioral needs are also fundamentally important for cat and dog wellness. First and foremost, they require freedom from fear and distress, as well as the freedom to express normal behavior. Most cats and dogs do not thrive in isolation; indeed, they are social animals, and thus the opportunity for social interactions represents a basic behavioral need. They also require the ability to create different functional areas in their living environments for elimination, resting, and eating. They require consistent routines or daily patterns of care, including consistent periods of light and darkness. Other important behavioral needs include the ability to find a hiding place, to sleep without being disturbed, and to be free of chronic harassment from humans, other animals, or environmental stressors. Cats and dogs also require mental stimulation and the ability to play and exercise at will. Finally, cats need to scratch, and dogs need to chew. For cats, scratching is a normal behavior that conditions the claws, serves as a visual and scent marker, and is a means of stretching. For dogs, chewing is a normal behavior that conditions the teeth, serves as a method of investigating their environment, and can be a healthy coping strategy because it provides a ready outlet to express a normal behavior.

      Most animals experience at least some degree of fear and stress at the time of admission to a shelter. The “four F's” are often used to describe common types of behaviors associated with these emotional states: they include fight, flight, fret/fidget, and freeze behaviors. When fearful and stressed, some animals will display “fight” behaviors, such as struggling, growling, snarling, hissing, biting, or lunging, in an attempt to drive away a perceived threat. Others may display “flight behaviors” such as cowering, looking away, or moving away to escape, hide, or otherwise avoid contact. Still others will display “fret or fidget” behaviors: for example, they might move restlessly, nervously lick their lips, pace or shift about. And, some will display “freeze” behaviors: they may appear tense or frozen in a helpless state. Many stressed and fearful animals display a mixture of these fight, flight, fret/fidget, and freeze behaviors.

Manifestations of normal and abnormal behavior can indicate how successfully an animal is coping with its environment. In animal shelters, behavioral expressions of fear, anxiety, stress and/or frustration commonly manifest via inhibited or withdrawal, defensive, disruptive, and/or stereotypic behavior (Hubrecht 1993; Overall 1997). Inhibited or withdrawal behavior refers to activity depression or the absence of normal behaviors (such as grooming, eating, sleeping, eliminating, stretching, greeting people, etc.). Defensive behavior involves characteristic postural and/or vocal responses (e.g. barking, growling, lunging, hissing, swatting). Disruptive behavior involves the destruction of cage contents and/or the creation of a hiding place. Repetitive pacing, pawing, jumping and spinning are examples of stereotypic behaviors. Behavioral signs of stress and related negative emotional states may manifest as active communication signals or passive behaviors. Active signals may be subtle or obvious and include vocalization (growling, hissing), visual cues (facial expression, posturing of the body, ears, and tail), scent marking (urine, feces, various glands of the skin), and overt aggression among others. Passive signs include the inability to rest or sleep, feigned sleep, poor appetite, constant hiding, the absence of grooming, activity depression (decreased play and exploratory behavior) and social withdrawal (Griffin 2006; Rochlitz et al. 1998; Wemelsfelder 2005). High‐density housing exacerbates these signs.

      When cats and dogs are well adjusted and their housing and husbandry meet their behavioral needs, they display a wide variety of normal behaviors. Indeed, the best measures of emotional wellbeing and health in shelter cats and dogs are regular displays of species typical behaviors – in other words, cats should be “acting like cats” and dogs should be “acting like dogs”: sleeping comfortably, but not all the time; exploring and playing at will; eating and eliminating normally; scratching or chewing; stretching and grooming; relaxing; seeking and receiving social contact – behaviors that, when displayed regularly and appropriately, indicate positive emotional states and good health.

      Proper housing and enrichment, including social companionship, physical exercise, mental stimulation, and positive training, combined with a positive emotional environment are essential components of a comprehensive behavioral wellness program (see Table 2.2). Understanding the importance of minimizing stress and other negative emotional states and recognizing and responding to them are keys to maintaining proper behavioral welfare. Active daily monitoring by staff who are trained to recognize indicators of stress, fear, anxiety, and frustration is required to detect and respond to the needs of animals that are displaying these indicators. Some indicators that an animal needs additional attention include persistent hiding, agonistic behavior with conspecifics, activity withdrawal, or other markers as previously described. Staff should record their findings daily to ensure timely and appropriate steps are taken to decrease stress and enhance the animal's ability to cope in the shelter environment. Though subjective, staff should also attempt to estimate the severity of stress and note trends: What is the animal's emotional state? Is the animal acclimating to the environment?