Construction and in vitro characterisation of virus-vectored immunocontraceptive candidates derived from felid alphaherpesvirus 1.

There is a pressing need for effective feral cat management globally due to overabundant feline populations, disease transmission and their destructive impact on biodiversity. Virus-vectored immunocontraception (VVIC) is an attractive method for cat population management. Virus-vectored immunocontraceptives could be self-disseminating through horizontal transmission of the VVIC in feral cat populations, or they may be modified to act as non-transmissible vaccine-type immunocontraceptives for delivery to individual cats. These later constructs may be particularly attractive for use in owned (pet) cats and stray cats but could also be used for feral cats that are caught, vaccinated, and released. Here, we report the construction of three felid alphaherpesvirus 1 (FHV-1) derived immunocontraceptive candidates containing genes that encode for feline zona pellucida subunit 3 (ZP3) and gonadotropin-releasing hormone (GnRH). Two of the vaccine candidates were engineered to include disruptions to the thymidine kinase viral virulence gene to reduce the ability of the vaccines to be horizontally transmitted. Analysis of in vitro growth characteristics and protein expression are reported, and their potential for use as a population management tool for cats is discussed.

Hierarchical modelling of immunoglobulin coated bacteria in dogs with chronic enteropathy shows reduction in coating with disease remission but marked inter-individual and treatment-response variability.

Chronic enteropathies are a common problem in dogs, but many aspects of the pathogenesis remain unknown, making the therapeutic approach challenging in some cases. Environmental factors are intimately related to the development and perpetuation of gastrointestinal disease and the gut microbiome has been identified as a contributing factor. Previous studies have identified dysbiosis and reduced bacterial diversity in the gastrointestinal microbiota of dogs with chronic enteropathies. In this case-controlled study, we use flow cytometry and 16S rRNA sequencing to characterise bacteria highly coated with IgA or IgG in faecal samples from dogs with chronic enteropathy and evaluated their correlation with disease and resolution of the clinical signs. IgA and IgG-coated faecal bacterial counts were significantly higher during active disease compared to healthy dogs and decreased with the resolution of the clinical signs. Characterisation of taxa-specific coating of the intestinal microbiota with IgA and IgG showed marked variation between dogs and disease states, and different patterns of immunoglobulin enrichment were observed in dogs with chronic enteropathy, particularly for Erysipelotrichaceae, Clostridicaceae, Enterobacteriaceae, Prevotellaceae and Bacteroidaceae, families. Although, members of these bacterial groups have been associated with strong immunogenic properties and could potentially constitute important biomarkers of disease, their significance and role need to be further investigated.

Use of feline herpesvirus as a vaccine vector offers alternative applications for feline health.

Herpesviruses are attractive vaccine vector candidates due to their large double stranded DNA genome and latency characteristics. Within the scope of veterinary vaccines, herpesvirus-vectored vaccines have been well studied and commercially available vectored vaccines are used to help prevent diseases in different animal species. Felid alphaherpesvirus 1 (FHV-1) has been characterised as a vector candidate to protect against a range of feline pathogens. In this review we highlight the methods used to construct FHV-1 based vaccines and their outcomes, while also proposing alternative uses for FHV-1 as a viral vector.

Assessment of serum symmetric dimethylarginine and creatinine concentrations in hyperthyroid cats before and after a fixed dose of orally administered radioiodine.

BACKGROUND: Serum symmetric dimethylarginine (SDMA) is a sensitive renal biomarker for detecting early chronic kidney disease (CKD) in nonhyperthyroid cats, but knowledge regarding its performance in hyperthyroid cats remains limited. OBJECTIVES: To determine the relationship between serum SDMA, creatinine and total thyroxine (TT4) concentrations in hyperthyroid cats before (T0) and 3 months after (T1) receiving a PO fixed dose of radioiodine. ANIMALS: Eighty client-owned hyperthyroid cats. METHODS: Prospective cohort study. Serum TT4, and SDMA, creatinine concentrations, and urine specific gravity were measured at T0 and T1. Nonparametric tests were used to determine the relationship among SDMA, and creatinine and TT4 concentrations. Agreement between SDMA and creatinine regarding CKD staging at both time points was assessed using Goodman and Kruskal's gamma statistic. RESULTS: Mean serum SDMA concentration increased after treatment of hyperthyroidism. However, 21 of 75 cats experienced a decrease in SDMA between T0 and T1, whereas creatinine decreased in only 2 cats. A moderate correlation between SDMA and creatinine was seen at T1 (r = 0.53; P < .001) but not at T0 (r = 0.13; P = .25). Where assessable at T1, poor agreement was observed between SDMA and creatinine and CKD stage (Goodman and Kruskal's gamma 0.20; P = .29). CONCLUSIONS AND CLINICAL IMPORTANCE: Discordant outcomes between SDMA and creatinine after radioiodine treatment in cats with hyperthyroidism suggest extrarenal factors may interfere with the reliability of SDMA to adequately reflect renal function. As a result, SDMA should not be interpreted in isolation in hyperthyroid cats treated with radioiodine.

Urine creatinine concentration and urine protein-to-creatinine ratios in healthy nonracing Greyhounds.

BACKGROUND: Serum creatinine concentrations are higher in Greyhounds when compared with nonsighthound breeds. Greyhounds might also have higher urine creatinine concentrations compared with other breeds, which could affect urine protein-to-creatinine ratio (UPC) references. OBJECTIVES: We aimed to determine the UPC reference intervals (RIs) in healthy nonracing Greyhounds and compare this with UPC values in a group of healthy nonsighthounds and with the current International Renal Interest Society (IRIS) guidelines. METHODS: The study used an observational cross-sectional design, involving clinically healthy, nonracing Greyhounds (n = 98) and nonsighthound dogs of similar weight, age, and sex (n = 24). Packed cell volumes, total solids, urine protein concentrations, serum and urine creatinine concentrations, urine specific gravity (USG) measurements, and UPCs were determined. Linear regression was used to compare urine creatinine and urine protein concentrations, relative to the USG measurements, between Greyhound and nonsighthound groups. Greyhound UPC RIs were determined using nonparametric methods and compared with UPC values in nonsighthounds and current IRIS guidelines. RESULTS: Mean urine creatinine concentrations, adjusted for USGs, were approximately 22% higher in Greyhounds compared with nonsighthounds (P = .002). Mean urine protein concentration (P = .46) and UPC (P = .1) were not significantly different between Greyhounds and nonsighthounds. The upper limit of the Greyhound UPC RI was 0.20 or 0.42, depending on whether strict or moderate exclusion criteria were applied, respectively. CONCLUSIONS: Greyhounds have higher urine creatinine concentrations than nonsighthounds. Although the suggested RI for UPCs in Greyhounds is slightly lower than the cut-offs recommended in generic canine IRIS guidelines, this difference is not likely to be clinically significant.

Assessment of treatment outcomes in hyperthyroid cats treated with an orally administered fixed dose of radioiodine.

OBJECTIVES: The aims of this study were to describe the treatment outcomes following oral administration of a fixed dose (138 MBq; 3.7 mCi) of radioiodine in hyperthyroid cats and to examine the correlation between total thyroxine (TT4) concentrations before and after treatment. METHODS: This was a retrospective cohort study that documented the TT4 concentration and clinicopathological parameters at the time of diagnosis and after treatment. Logistic regression was used to assess the relationship between TT4 concentrations before and after treatment. The difference in pre- and post-treatment variables between cats that had TT4 concentrations below or within the reference interval (RI) was compared by the Mann-Whitney U-test. RESULTS: Of 161 cats, 133 (82.6%) cats had TT4 concentrations within the RI, four (2.5%) cats had TT4 concentrations above the RI and 24 (14.9%) cats had TT4 concentrations below the RI after treatment. The severity of hyperthyroidism at diagnosis, as measured by the percentage of TT4 elevation above the upper limit of the RI, had no impact on the odds of cats having low TT4 concentrations after treatment (odds ratio 1.00; 95% confidence interval 0.96-1.05; P = 0.828). CONCLUSIONS AND RELEVANCE: When using an orally administered fixed dose of radioiodine for the treatment of feline hyperthyroidism, TT4 concentrations at diagnosis cannot be used to predict TT4 concentrations after treatment. The proportion of cats with TT4 concentrations below the lower limit of the RI after treatment was 14.9%. Further work is required to optimise oral radioiodine dosing to achieve maximal euthyroid outcomes.

Toxoplasmosis as a cause of life-threatening respiratory distress in a dog receiving immunosuppressive therapy.

Disseminated toxoplasmosis is a potentially fatal complication in dogs receiving immunosuppressive therapy, particularly if multiple immunosuppressive drugs are used. Toxoplasmosis should be considered if signs of acute respiratory or hepatic disease develop, and diagnosis would rely on demonstration of organisms via cytology or PCR rather than a single time-point serological assay.

Establishment of reference intervals for serum symmetric dimethylarginine in adult nonracing Greyhounds.

BACKGROUND: The reference intervals (RIs) for the renal biomarkers urea and creatinine, in Greyhounds, are higher than those for non-sighthound breeds. A recent study has demonstrated a higher concentration of another biomarker of renal function, symmetric dimethylarginine (SDMA), in Greyhounds compared with other dog breeds, and thus a breed-specific RI for serum SDMA may be appropriate for Greyhounds. Greyhounds appear to be predisposed to renal disease, and the establishment of an appropriate RI for SDMA may improve the ability to identify early renal dysfunction in this breed. OBJECTIVES: The aim of this study was to establish an RI for serum SDMA in nonracing Greyhounds and to determine whether the RI for Greyhounds is different from that of non-sighthound breeds. METHODS: Blood samples were collected from 101 clinically healthy, nonracing Greyhounds for serum SDMA measurements. Results from Greyhounds were compared with serum SDMA concentrations measured in a group of non-sighthound dogs (n = 24) of similar weight, age, and sex, and with a previously established canine serum SDMA RI. RESULTS: The serum SDMA RI for Greyhounds was 6.3-19.9 µg/dL (0.31-0.99 µmol/L). Greyhounds had a significantly higher mean value (13.1 µg/dL) than that of the non-sighthound dogs (10.2 µg/dL) (P < .001), and the RI of Greyhounds was different from previously established canine RIs for SDMA. CONCLUSION: This study supports the use of a Greyhound-specific RI for SDMA. Using previously established canine RIs for this breed could result in the overdiagnosis of renal disease.

The effect of recumbency position on the ultrasound measurement of the canine adrenal gland in non-adrenal gland illness.

Abdominal ultrasound is frequently used to assess the canine adrenal gland (AG) and subjective and objective features of normal AGs have been described. The effect of the dogs' recumbency position on the accuracy of AG measurement acquisition is not known. This prospective study, performed in dogs with non-adrenal illness, compared ultrasonographic AG measurements made in dogs placed in dorsal recumbency with those made in left or right lateral recumbency. AG length, height and width measurements made in the longitudinal image plane, and height and width measurements from the transverse image plane were assessed. The level and limits of agreement between the dorsal and lateral recumbency for each of the measurements were determined using the Bland-Altman analysis. The measurement with the best agreement between the dorsal and lateral recumbency was the caudal pole thickness (CPT) from the longitudinal image plane. Agreement between lateral and dorsal recumbency was poorer for the measurements derived from the transverse image plane and poorest for measurements of AG length in the longitudinal plane. This study demonstrates that there is some difference in the measurements acquired in dorsal compared with lateral recumbency; however, the difference is small for the CPT from the longitudinal plane. This finding suggests that the CPT from the longitudinal image plane is the most reliable measurement in terms of agreement between dorsal and lateral recumbency in dogs with non-AG illness.

IMAGING DIAGNOSIS-THE COMPUTED TOMOGRAPHY FEATURES OF A PLEUROPERITONEAL HERNIA IN A CAT.

An 8-year-old female neutered domestic short hair cat presented for investigation of poorly controlled diabetes mellitus. Thoracic radiographs identified a soft tissue opacity in the caudoventral thorax adjacent to the diaphragm. Computed tomography (CT) then characterized a pleuroperitoneal hernia with cranial displacement of a portion of the liver within the hernia. A pleuroperitoneal hernia was confirmed and repaired via exploratory laparotomy. This is the first description of the CT features of a pleuroperitoneal hernia in a cat.

Long-term survival and quality of life in dogs with clinical signs associated with a congenital portosystemic shunt after surgical or medical treatment.

OBJECTIVE: To compare long-term survival and quality of life data in dogs with clinical signs associated with a congenital portosystemic shunt (CPSS) that underwent medical or surgical treatment. DESIGN: Prospective cohort study. ANIMALS: 124 client-owned dogs with CPSS. PROCEDURES: Dogs received medical or surgical treatment without regard to signalment, clinical signs, or clinicopathologic results. Survival data were analyzed with a Cox regression model. Quality of life information, obtained from owner questionnaires, included frequency of CPSS-associated clinical signs (from which a clinical score was derived), whether owners considered their dog normal, and (for surgically treated dogs) any ongoing medical treatment for CPSS. A Mann-Whitney U test was used to compare mean clinical score data between surgically and medically managed dogs during predetermined follow-up intervals. RESULTS: 97 dogs underwent surgical treatment; 27 were managed medically. Median follow-up time for all dogs was 1,936 days. Forty-five dogs (24 medically managed and 21 surgically managed) died or were euthanized during the follow-up period. Survival rate was significantly improved in dogs that underwent surgical treatment (hazard ratio, 8.11; 95% CI, 4.20 to 15.66) than in those treated medically for CPSS. Neither age at diagnosis nor shunt type affected survival rate. Frequency of clinical signs was lower in surgically versus medically managed dogs for all follow-up intervals, with a significant difference between groups at 4 to 7 years after study entry. CONCLUSIONS AND CLINICAL RELEVANCE: Surgical treatment of CPSS in dogs resulted in significantly improved survival rate and lower frequency of ongoing clinical signs, compared with medical management. Age at diagnosis did not affect survival rate and should not influence treatment choice.