Effect of a Pheromone on Stress-Associated Reactivation of Feline Herpesvirus-1 in Experimentally Inoculated Kittens

First study on stress evaluation and reduction in hospitalized cats after neutering surgery

Background and Aim:

In Thailand, domestic cats are the most common companion animal, and many are admitted to veterinary clinics for neutering surgery; however, such environment can induce stress. This is the first study to evaluate stress in hospitalized cats after neutering surgery using cat stress score (CSS) and salivary cortisol levels, including the impact of providing a hiding box (B) and/or administering a pheromone product to reduce stress.

Materials and Methods:

The study design was based on a randomized controlled clinical trial. A total of 80 domestic cats undergoing routine neutering surgery were assessed for their behavioral demeanor scoring system (DSS) as friendly (DSS1) and aggressive (DSS2) based on a DSS. During admission, the cats were randomly allocated to single standard cages with one of the following treatments: (B), feline facial pheromone (P), a combination of hiding box and the pheromone (BP), or no additional enrichment (C). Cat stress score, food intake, and hide-seeking behavior were recorded. The cortisol enzyme-linked immunosorbent assay kit was used to assess the salivary cortisol level.

Results:

On the 1^st day of admission, aggressive cats had a significantly higher CSS (4.16 ± 0.29) than friendly cats (3.27 ± 0.16). Both demeanor cat groups showed statistically significant reductions in stress levels earlier than the control group after providing the enrichments. Saliva cortisol measurements ranged from 0.24 to 0.66 ng/mL. No statistical differences in cortisol levels were observed between the 1^st day and other days of admission. In contrast, no differences in food intake and hide-seeking behavior were seen within each group during the same period.

Conclusion:

Results suggested that stress and stress responses in cats depended on behavioral demeanor. The provision of enrichment, including hiding box and feline facial pheromone in singly housed caging reduced stress, especially in aggressive cats. However, salivary cortisol analysis, food intake, and hide-seeking behavior were ineffective for assessing stress in cats after neutering surgery.

Dealing With Stress in Cats: What Is New About the Olfactory Strategy?

Domestic cats are descended from solitary wild species and rely heavily on the olfaction system and chemical signals for daily activities. Cats kept as companion animals may experience stress due to a lack of predictability in their physical or social environment. The olfactory system is intimately connected to the brain regions controlling stress response, thus providing unique opportunities for olfactory strategies to modify stress and related behavioral problems in cats. However, the olfactory intervention of stress in cats has been mainly focused on several analog chemical signals and studies often provide inconsistent and non-replicable results. Supportive evidence in the literature for the potentially effective olfactory stimuli (e.g., cheek and mammary gland secretions, and plant attractants) in treating stress in cats was reviewed. Limitations with some of the work and critical considerations from studies with natural or negative results were discussed as well. Current findings sometimes constitute weak evidence of a reproducible effect of cat odor therapy for stress. The welfare application of an olfactory stimulus in stress alleviation requires a better understanding of its biological function in cats and the mechanisms at play, which may be achieved in future studies through methodological improvement (e.g., experiment pre-registration and appropriate control setting) and in-depth investigation with modern techniques that integrate multisource data. Contributions from individual and environmental differences should be considered for the stress response of a single cat and its sensitivity to olfactory manipulation. Olfactory strategies customized for specific contexts and individual cats can be more effective in improving the welfare of cats in various stressful conditions.

Comparative Efficacy of Topical Ophthalmic Ganciclovir and Oral Famciclovir in Cats with Experimental Ocular Feline Herpesvirus-1 Epithelial Infection

Purpose: To determine the comparative efficacy of ganciclovir ophthalmic gel and famciclovir oral tablets in cats with experimentally induced ocular feline herpesvirus-1 (FHV-1) epithelial infection. Methods: A randomized, placebo-controlled trial was performed using 16 nonvaccinated, specific pathogen-free cats with experimental FHV-1 infection induced by topical ocular inoculation. Cats received topical ganciclovir 0.15% ophthalmic gel (1 drop 3 times daily, n = 6 cats), oral famciclovir (90 mg/kg twice daily, n = 6), or topical artificial tear gel (1 drop 3 times daily, n = 4) for 14 days. Cats were monitored after inoculation for 30 days. Ophthalmic examinations were performed every 2 days and ocular disease scores calculated. In vivo confocal microscopy was performed, and corneal leukocyte infiltrates quantified. Ocular samples for FHV-1 quantitative polymerase chain reaction (qPCR) and virus isolation assays were collected every 3 days. Hemograms and serum biochemistry panels were performed at intervals. Results: Clinical ocular disease scores and corneal leukocyte infiltrates were significantly lower in the ganciclovir and famciclovir groups compared with placebo, but no significant differences were detected between the antiviral treatment groups. Ocular viral loads determined by qPCR were significantly lower in the ganciclovir group compared with the placebo group, but there were no significant differences between the other study groups. Hemograms and biochemistry panels were unremarkable. Conclusion: Topical application of ganciclovir gel 3 times daily was well-tolerated and displayed similar efficacy at reducing clinical ocular disease scores and corneal inflammation as twice daily oral famciclovir treatment in cats with experimental ocular FHV-1 infection.

Evaluation of hair and nail cortisol concentrations and associations with behavioral, physical, and environmental indicators of chronic stress in cats

Background

Chronic stress is implicated in behavioral and health issues in cats, but methods for recognition, evaluation, and measurement of stress are lacking. Cortisol concentration is typically used as an indicator of stress.

Objectives

To evaluate use of an enzyme immunoassay to quantitate hair and nail cortisol concentrations (HCC and NCC) in cats and evaluate associations between HCC and NCC and behavioral, physical, and environmental correlates of chronic stress in cats.

Animals

Forty‐eight adult, owned or community cats.

Methods

Cross‐sectional study. Nail clippings and hair were collected from cats. Medical history and cat daily lifestyle questionnaires were completed by owners or caretakers. A commercial laboratory performed cortisol extraction and quantification using a validated enzyme immunoassay kit. Correlational and regression analyses were used to evaluate associations between HCC and NCC and behavioral, environmental, and medical factors.

Results

Hair and nail cortisol concentrations were significantly associated (r_s = 0.70; P < .001), but HCCs varied widely within and among cats. Cats with litterbox issues had significantly increased HCC (P = .02) and NCC (P = .001) as compared to cats without litterbox issues. Cats with groomed coats had lower HCCs (P = .02) as compared to cats without groomed coats, whereas cats with dander and mats had higher NCCs (P = .01) as compared to cats without dander and mats.

Conclusions and Clinical Importance

The quantification of NCCs might improve identification and evaluation of chronic stress in cats. The variability of HCCs in individual cats warrants caution using this measurement in chronic stress studies.

The Behavioural Effects of Innovative Litter Developed to Attract Cats

Urination and/or defecation outside a designated location has been reported as the most common behavioural reason for surrendering a cat and comprises approximately 30% of cat intakes to shelters. The objective of this study was to determine whether cats would increase in-box elimination when provided a plant-based litter product with attractant (ATTRACT) compared to the same plant-based litter product without attractant (PLANT). Sixteen cats were split into two equal cohorts based on availability from the shelter and group-housed in an enriched room with eight identical litter boxes arranged in a circular pattern equidistant from each other. Following a two-week room acclimation and transition period from clay litter to PLANT litter, boxes were designated either PLANT or ATTRACT litter, balancing for cats' prior box location preferences. For 14 days following litter allocation, cat behaviours such as sniffing, digging, covering, urinating, and defecating were video recorded for 12 h daily. The cats urinated more often in the ATTRACT litter, suggesting that they preferred the ATTRACT litter for urination more than the PLANT litter (p < 0.05). The most significant differences observed were between genders, with males spending significantly more time sniffing and performing urination behaviours (p < 0.05). These results suggest that litter with an attractant may be more effective in eliciting usage for urination, as compared to a litter without the additive.

Tools for Managing Feline Problem Behaviors: Pheromone therapy

PRACTICAL RELEVANCE

Cats are one of the most common companion animals in the world. However, relatively little scientific research has been conducted on cat behavior. With problem behaviors a leading reason for relinquishment of cats to shelters, or abandonment outdoors, solutions to address feline behavioral problems can have important welfare benefits. Because naturally occurring pheromones produce measurable species-specific responses in cats, the use of synthetic pheromone products consisting of the same compounds may activate a specific behavioral response in the receiving individual, allowing humans to better communicate with cats and manage feline problem behavior.

AIMS

In this article the scientific background for naturally occurring feline pheromones and semiochemicals and their impact on cat behavior is reviewed. This is used as a foundation to explore the three feline synthetic pheromones currently available and the empirical evidence that exists for their effectiveness. From this information, several recommendations for veterinarians and behavior professionals on the application of feline pheromone therapy in the home and veterinary clinic setting are presented.

EVIDENCE BASE

The efficacy of synthetic pheromones as a tool for the management of problem behaviors is a relatively new area of research and only fairly recently has the need to implement more rigorous research methodology been recognized.

Evaluation of liposome toll-like receptor ligand complexes for non-specific mucosal immunoprotection from feline herpesvirus-1 infection

Background

Feline herpesvirus‐1 (FHV‐1) infection can result in serious morbidity and mortality, especially in kittens. Immunotherapy using liposome‐toll‐like receptor (TLR) ligand complexes (LTC) has been shown to activate innate immune responses.

Objectives

To determine in kittens whether mucosal administration of LTC before FHV‐1 inoculation would decrease severity of clinical signs and decrease quantities of FHV‐1 DNA in materials collected on oropharyngeal swabs.

Animals

Nineteen, 14‐week‐old, purpose‐bred kittens.

Methods

Pilot clinical trial with 2 groups of kittens allocated to either an LTC or control group. The LTC were administered into both nares and the oropharynx of the 12 LTC group kittens, and all 19 kittens were inoculated with FHV‐1 24 hours later. Clinical scores were determined daily for 28 days, and oropharyngeal mucosal materials were collected every 7 days to assess FHV‐1 DNA quantities for comparison between groups.

Results

Conjunctivitis was more common in kittens in the control group on Days 15‐28 (P = .01) and Days 1‐28 (P = .02). Total respiratory scores were higher in the LTC group on days 15‐28 (P = .03). The LTC group had significantly decreased FHV‐1 DNA on swabs when compared to the control group on some postinoculation days, using 2 methods of calculation.

Conclusions and Clinical Importance

Administration of LTC to kittens was shown to decrease FHV‐1 DNA and some manifestations of illness in kittens when administrated 24 hours before inoculation, suggesting clinical benefit.