Clinical features and long-term management of cats with primary hypoadrenocorticism using desoxycorticosterone pivalate and prednisolone.

BACKGROUND: Primary hypoadrenocorticism (PH) is rare in cats and knowledge about treatment is sparse. OBJECTIVE: To describe cats with PH with a focus on long-term treatment. ANIMALS: Eleven cats with naturally occurring PH. METHODS: Descriptive case series with data on signalment, clinicopathological findings, adrenal width, and doses of desoxycorticosterone pivalate (DOCP) and prednisolone during a follow-up period of >12 months. RESULTS: Cats ranged from 2 to 10 years (median 6.5); 6 cats were British Shorthair. Most common signs were reduced general condition and lethargy, anorexia, dehydration, obstipation, weakness, weight loss, and hypothermia. Adrenal glands on ultrasonography were judged small in 6. Eight cats could be followed for 14 to 70 months (median: 28). Two were started on DOCP doses ≥2.2 mg/kg (2.2; 2.5) and 6 < 2.2 mg/kg (1.5-2.0 mg/kg, median 1.8) q28 days. Both high-dose cats and 4 low-dose cats needed a dose increase. Desoxycorticosterone pivalate and prednisolone doses at the end of the follow-up period were 1.3 to 3.0 mg/kg (median: 2.3) and 0.08 to 0.5 mg/kg/day (median: 0.3), respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Desoxycorticosterone pivalate and prednisolone requirements in cats were higher than what is currently used in dogs; thus, a DOCP starting dose of 2.2 mg/kg q28 days and a prednisolone maintenance dose of 0.3 mg/kg/day titrated to the individual need seems warranted. Small adrenal glands (width < 2.7 mm) on ultrasonography in a cat suspected of hypoadrenocorticism can be suggestive of the disease. The apparent predilection of British Shorthaired cats for PH should be further evaluated.

Effects of ACTH-Induced Long-Term Hypercortisolism on the Transcriptome of Canine Visceral Adipose Tissue.

Cushing's syndrome, or hypercortisolism (HC), a common endocrinopathy in adult dogs, is caused by chronic hypercortisolemia. Among different metabolic disorders, this syndrome is associated with enhanced subcutaneous lipolysis and visceral adiposity. However, effects of HC in adipose tissue, especially regarding visceral adipose tissue (VAT), are still poorly understood. Herein, the transcriptomic effects of chronic HC on VAT of dogs were evaluated. For this, subcutaneously implanted ACTH-releasing pumps were used, followed by deep RNA sequencing of the canine VAT. Prolonged HC seems to affect a plethora of regulatory mechanisms in VAT of treated dogs, with 1190 differentially expressed genes (DEGs, p and FDR < 0.01) being found. The 691 downregulated DEGs were mostly associated with functional terms like cell adhesion and migration, intracellular signaling, immune response, extracellular matrix and angiogenesis. Treatment also appeared to modulate local glucocorticoid and insulin signaling and hormonal sensitivity, and several factors, e.g., TIMP4, FGF1, CCR2, CXCR4 and HSD11B1/2, were identified as possible important players in the glucocorticoid-related expansion of VAT. Modulation of their function during chronic HC might present interesting targets for further clinical studies. Similarities in the effects of chronic HC on VAT of dogs and humans are highlighted.

Serum Lipidome Signatures of Dogs with Different Endocrinopathies Associated with Hyperlipidemia.

Hyperlipidemia (hypertriglyceridemia, hypercholesterolemia) is a common finding in human and veterinary patients with endocrinopathies (e.g., hypothyroidism and hypercortisolism (Cushing's syndrome; CS)). Despite emerging use of lipidomics technology in medicine, the lipid profiles of these endocrinopathies have not been evaluated and characterized in dogs. The aim of this study was to compare the serum lipidomes of dogs with naturally occurring CS or hypothyroidism with those of healthy dogs. Serum samples from 39 dogs with CS, 45 dogs with hypothyroidism, and 10 healthy beagle dogs were analyzed using a targeted lipidomics approach with liquid chromatography-mass spectrometry. There were significant differences between the lipidomes of dogs with CS, hypothyroidism, and the healthy dogs. The most significant changes were found in the lysophosphatidylcholines, lysophosphatidylethanolamines, lysophosphatidylinositols, phosphatidylcholines, phosphatidylethanolamines, phosphatidylglycerols, ceramides, and sphingosine 1-phosphates. Lipid alterations were especially pronounced in dogs with hypothyroidism. Several changes suggested a more atherogenic lipid profile in dogs with HT than in dogs with CS. In this study, we found so far unknown effects of naturally occurring hypothyroidism and CS on lipid metabolism in dogs. Our findings provide starting points to further examine differences in occurrence of atherosclerotic lesion formation between the two diseases.

Evaluation of symmetric dimethylarginine and creatinine in dogs with primary hypoadrenocorticism receiving long-term mineralocorticoid replacement therapy.

OBJECTIVES: To investigate kidney function by determining serum symmetric dimethylarginine (sSDMA) and serum creatinine (sCr) concentrations in dogs with primary hypoadrenocorticism (PH) receiving long-term mineralocorticoid replacement therapy. METHODS: Dogs with PH receiving a minimum of 12 months of either desoxycorticosterone pivalate or fludrocortisone acetate were included in the study provided that banked frozen serum samples were available for sSDMA analysis. sCr concentrations were retrieved from the medical records. In dogs still alive and presented for regular re-evaluations and in newly diagnosed patients, blood was prospectively collected for sSDMA and sCr determination. RESULTS: Thirty-two dogs met the inclusion criteria. The treatment time ranged from 12 to 146 months after initial diagnosis (median, 55.5 months). The majority of dogs had normal sSDMA and sCr concentrations throughout the hormone replacement treatment. Both sSDMA and sCr concentrations were persistently elevated in three of 32 dogs. Further workup confirmed chronic kidney disease (CKD) in all three dogs. CONCLUSIONS: Based on these data, the prevalence of CKD could be higher in dogs with PH receiving long-term mineralocorticoid replacement treatment than in the general dog population. However, additional studies with a larger number of dogs are needed to confirm it.

Modified-Live Feline Calicivirus Vaccination Elicits Cellular Immunity against a Current Feline Calicivirus Field Strain in an Experimental Feline Challenge Study.

Feline calicivirus (FCV) is a common cat virus associated with oral ulcerations and virulent-systemic disease. Efficacious FCV vaccines protect against severe disease but not against infection. The high genetic diversity of FCV poses a challenge in vaccine design. Protection against FCV has been related to humoral and cellular immunity; the latter has not been studied in detail. This study investigates the cellular and humoral immune response of specified pathogen-free (SPF) cats after modified-live FCV F9 vaccinations and two heterologous FCV challenges by the analysis of lymphocyte subsets, cytokine mRNA transcription levels, interferon (IFN)-γ release assays in peripheral blood mononuclear cells (PBMCs), anti-FCV antibodies, and neutralisation activity. Vaccinated cats developed a Th1 cytokine response after vaccination. Vaccination resulted in antibodies with neutralising activity against the vaccine but not the challenge viruses. Remarkably, IFN-γ-releasing PBMCs were detected in vaccinated cats upon stimulation with the vaccine strain and the first heterologous FCV challenge strain. After the first experimental infection, the mRNA transcription levels of perforin, granzyme B, INF-γ, and antiviral factor MX1 and the number of IFN-γ-releasing PBMCs when stimulated with the first challenge virus were higher in vaccinated cats compared to control cats. The first FCV challenge induced crossneutralising antibodies in all cats against the second challenge virus. Before the second challenge, vaccinated cats had a higher number of IFN-γ-releasing PBMCs when stimulated with the second challenge virus than control cats. After the second FCV challenge, there were less significant differences detected between the groups regarding lymphocyte subsets and cytokine mRNA transcription levels. In conclusion, modified-live FCV vaccination induced cellular but not humoral crossimmunity in SPF cats; innate immune mechanisms, secretory and membranolytic pathways, and IFN-γ-releasing PBMCs seem to be important in the host immune defence against FCV.

Modified-Live Feline Calicivirus Vaccination Reduces Viral RNA Loads, Duration of RNAemia, and the Severity of Clinical Signs after Heterologous Feline Calicivirus Challenge.

Feline calicivirus (FCV) is a common cat virus causing clinical signs such as oral ulcerations, fever, reduced general condition, pneumonia, limping and occasionally virulent-systemic disease. Efficacious FCV vaccines protect against severe disease but not against infection. FCV is a highly mutagenic RNA virus whose high genetic diversity poses a challenge in vaccine design. The use of only one modified-live FCV strain over several decades might have driven the viral evolution towards more vaccine-resistant variants. The present study investigated the clinical signs, duration, and amount of FCV shedding, RNAemia, haematological changes and acute phase protein reaction in SPF cats after subcutaneous modified-live single strain FCV vaccination or placebo injection and two subsequent oronasal heterologous FCV challenge infections with two different field strains. Neither clinical signs nor FCV shedding from the oropharynx and FCV RNAemia were detected after vaccination. After the first experimental infection, vaccinated cats had significantly lower clinical scores, less increased body temperature and lower acute phase protein levels than control cats. The viral RNA loads from the oropharynx and duration and amount of RNAemia were significantly lower in the vaccinated animals. No clinical signs were observed in any of the cats after the second experimental infection. In conclusion, FCV vaccination was beneficial for protecting cats from severe clinical signs, reducing viral loads and inflammation after FCV challenge.

Glycemic variability in newly diagnosed diabetic cats treated with the glucagon-like peptide-1 analogue exenatide extended release.

BACKGROUND: Glycemic variability (GV) is an indicator of glycemic control and can be evaluated by calculating the SD of blood glucose measurements. In humans with diabetes mellitus (DM), adding a glucagon-like peptide-1 (GLP-1) analogue to conventional therapy reduces GV. In diabetic cats, the influence of GLP-1 analogues on GV is unknown. OBJECTIVE: To evaluate GV in diabetic cats receiving the GLP-1 analogue exenatide extended release (EER) and insulin. ANIMALS: Thirty client-owned cats with newly diagnosed spontaneous DM. METHODS: Retrospective study. Blood glucose curves from a recent prospective placebo-controlled clinical trial generated 1, 3, 6, 10, and 16 weeks after starting therapy were retrospectively evaluated for GV. Cats received either EER (200 µg/kg) or 0.9% saline SC once weekly, insulin glargine and a low-carbohydrate diet. Mean blood glucose concentrations were calculated and GV was assessed by SD. Data were analyzed using nonparametric tests. RESULTS: In the EER group, GV (mean SD [95% confidence interval]) was lower at weeks 6 (1.69 mmol/L [0.9-2.48]; P = .02), 10 (1.14 mmol/L [0.66-1.62]; P = .002) and 16 (1.66 mmol/L [1.09-2.23]; P = .02) compared to week 1 (4.21 mmol/L [2.48-5.93]) and lower compared to placebo at week 6 (3.29 mmol/L [1.95-4.63]; P = .04) and week 10 (4.34 mmol/L [2.43-6.24]; P < .000). Cats achieving remission (1.21 mmol/L [0.23-2.19]) had lower GV compared to those without remission (2.96 mmol/L [1.97-3.96]; P = .01) at week 6. CONCLUSIONS AND CLINICAL IMPORTANCE: The combination of EER, insulin, and a low-carbohydrate diet might be advantageous in the treatment of newly diagnosed diabetic cats.

Bayesian Network Modeling Applied to Feline Calicivirus Infection Among Cats in Switzerland.

Bayesian network (BN) modeling is a rich and flexible analytical framework capable of elucidating complex veterinary epidemiological data. It is a graphical modeling technique that enables the visual presentation of multi-dimensional results while retaining statistical rigor in population-level inference. Using previously published case study data about feline calicivirus (FCV) and other respiratory pathogens in cats in Switzerland, a full BN modeling analysis is presented. The analysis shows that reducing the group size and vaccinating animals are the two actionable factors directly associated with FCV status and are primary targets to control FCV infection. The presence of gingivostomatitis and Mycoplasma felis is also associated with FCV status, but signs of upper respiratory tract disease (URTD) are not. FCV data is particularly well-suited to a network modeling approach, as both multiple pathogens and multiple clinical signs per pathogen are involved, along with multiple potentially interrelated risk factors. BN modeling is a holistic approach-all variables of interest may be mutually interdependent-which may help to address issues, such as confounding and collinear factors, as well as to disentangle directly vs. indirectly related variables. We introduce the BN methodology as an alternative to the classical uni- and multivariable regression approaches commonly used for risk factor analyses. We advise and guide researchers about how to use BNs as an exploratory data tool and demonstrate the limitations and practical issues. We present a step-by-step case study using FCV data along with all code necessary to reproduce our analyses in the open-source R environment. We compare and contrast the findings of the current case study using BN modeling with previous results that used classical regression techniques, and we highlight new potential insights. Finally, we discuss advanced methods, such as Bayesian model averaging, a common way of accounting for model uncertainty in a Bayesian network context.

Serum lipidome analysis of healthy beagle dogs receiving different diets.

INTRODUCTION: Food and dietary ingredients have significant effects on metabolism and health. OBJECTIVE: To evaluate whether and how different diets affected the serum lipidomic profile of dogs. METHODS: Sixteen healthy beagles were fed a commercial dry diet for 3 months (control diet). After an overnight fasting period, a blood sample was taken for serum lipidomic profile analysis, and each dog was then randomly assigned to one of two groups. Group 1 was fed a commercial diet (Diet 1) and group 2 was fed a self-made, balanced diet supplemented with linseed oil and salmon oil (Diet 2) for 3 months. After an overnight fasting period, a blood sample was taken from each dog. Serum cholesterol and triacylglycerol analyses were performed and the serum lipidomic profiles were analyzed using targeted liquid chromatography-mass spectrometry. RESULTS: Dogs fed the supplemented self-made diet (Diet 2) had significantly higher omega-3 fatty acid-containing lipids species and significantly lower saturated and mono- and di-unsaturated lipid species. Concentrations of sphingosine 1-phosphate species S1P d16:1 and S1P d17:1 were significantly increased after feeding Diet 2. CONCLUSION: This study found that different diets had significant effects on the dog's serum lipidomic profile. Therefore, in studies that include lipidomic analyses, diet should be included as a confounding factor.

Prevalence, Geographic Distribution, Risk Factors and Co-Infections of Feline Gammaherpesvirus Infections in Domestic Cats in Switzerland.

Recently, a gammaherpesvirus was described in domestic cats (FcaGHV1). The goal of the present study was to investigate the presence of FcaGHV1 in Swiss domestic cats and analyze potential risk factors. Blood samples from 881 cats presented to veterinarians in all Swiss cantons and from 91 stray cats and neoplastic tissue samples from 17 cats with lymphoma were evaluated. FcaGHV1 was detected by real-time PCR targeting the glycoprotein B gene, followed by sequencing. Blood samples were also tested for feline hemoplasmas, feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV). The molecular prevalence of FcaGHV1 was 6.0% (95% confidence interval (CI), 4.5-7.8%) in cats presented to veterinarians and 5.5% (95% CI, 1.8-12.4%) in stray cats. FcaGHV1 PCR-positive cats originated from 19/26 Swiss cantons. Factors significantly associated with FcaGHV1 detection included male sex, age >3 years, nonpedigree status and co-infection with FIV and hemoplasmas. Moreover, FeLV viremia tended to be associated with FcaGHV1 detection. High FcaGHV1 blood loads were found more frequently in FeLV-viremic cats and less frequently in hemoplasma-infected cats than in uninfected cats. Clinical information was unavailable for most of the 881 cats, but leukemia, carcinoma and cardiomyopathy were reported in FcaGHV1-positive cats. None of the tissue samples from the 17 cats with lymphoma tested positive for FcaGHV1. Sequence analyses revealed homogeneity among the Swiss isolates and >99.7% identity to published FcaGHV1 sequences. In conclusion, FcaGHV1 is present in Switzerland with a similar prevalence in cats presented to veterinarians and in stray cats. The pathogenic potential of FcaGHV1 needs further evaluation.

Changes in the Canine Plasma Lipidome after Short- and Long-Term Excess Glucocorticoid Exposure.

Glucocorticoids (GCs) are critical regulators of metabolic control in mammals and their aberrant function has been linked to several pathologies. GCs are widely used in human and veterinary clinical practice as potent anti-inflammatory and immune suppressive agents. Dyslipidaemia is a frequently observed consequence of GC treatment, typified by increased lipolysis, lipid mobilization, liponeogenesis, and adipogenesis. Dogs with excess GC show hyperlipidaemia, hypertension, and a higher risk of developing type 2 diabetes mellitus, but the risk of developing atherosclerotic lesions is low as compared to humans. This study aimed to examine alterations in the canine plasma lipidome in a model of experimentally induced short-term and long-term GC excess. Both treatments led to significant plasma lipidome alterations, which were more pronounced after long-term excess steroid exposure. In particular, monohexosylceramides, phosphatidylinositols, ether phosphatidylcholines, acyl phosphatidylcholines, triacylglycerols and sphingosine 1-phosphates showed significant changes. The present study highlights the hitherto unknown effects of GCs on lipid metabolism, which will be important in the further elucidation of the role and function of GCs as drugs and in metabolic and cardiovascular diseases.

Evaluation of a low-dose desoxycorticosterone pivalate treatment protocol for long-term management of dogs with primary hypoadrenocorticism.

BACKGROUND: Lowering the dose of desoxycorticosterone pivalate (DOCP) for the treatment of dogs with primary hypoadrenocorticism (PH) decreases costs and could lead to increased owner motivation to treat their affected dogs. OBJECTIVE: To evaluate the efficacy of a low-dose DOCP treatment protocol in dogs with PH. ANIMALS: Prospective study, 17 client-owned dogs with naturally occurring PH (12 newly diagnosed, 5 previously treated with fludrocortisone acetate [FC]). METHODS: Dogs with newly diagnosed PH were started on 1.5 mg/kg DOCP SC; dogs previously treated with FC were started on 1.0-1.8 mg/kg DOCP SC. Reevaluations took place at regular intervals for a minimum of 3 months and included clinical examination and determination of serum sodium and potassium concentrations. The DOCP dosage was adjusted to obtain an injection interval of 28-30 days and to keep serum electrolyte concentrations within the reference interval. RESULTS: Median (range) follow-up was 16.2 months (4.5-32.3 months). The starting dosage was sufficient in all but 2 dogs and had to be significantly decreased after 2-3 months to a median dosage (range) of 1.1 mg/kg (0.7-1.8). Dogs 3 years of age or younger needed significantly higher dosages compared to older dogs. None of them, however, needed the 2.2 mg/kg DOCP dosage, recommended by the manufacturer. CONCLUSIONS AND CLINICAL IMPORTANCE: A starting dosage of 1.5 mg/kg DOCP is effective in controlling clinical signs and serum electrolyte concentrations in the majority of dogs with PH. An additional dose reduction often is needed to maintain an injection interval of 28-30 days. Young and growing animals seem to need higher dosages.

Consecutive antibiotic treatment with doxycycline and marbofloxacin clears bacteremia in Mycoplasma haemofelis-infected cats.

Mycoplasma haemofelis is the most pathogenic feline hemoplasma species and a causative agent of infectious hemolytic anemia in cats. Current treatment protocols are effective in reducing M. haemofelis blood loads and clinical signs but consistent bacteremia clearance is rarely achieved. The aim of this study was to develop an antibiotic treatment protocol capable of clearing M. haemofelis bacteremia. Doxycycline and marbofloxacin treatment protocols were evaluated in chronically M. haemofelis infected cats in two pre-experiments and a controlled treatment study (main experiment) using five treated and four untreated cats. The blood bacterial loads in the main experiment were monitored weekly by real-time PCR for 203 days. Cats were treated with doxycycline (5 mg/kg bid orally) for 28 days. Cats that remained M. haemofelis PCR-positive or became positive again (all 5 cats in the main experiment) were switched to marbofloxacin treatment (2 mg/kg sid orally) for 14 days; then, all cats were PCR-negative. Immunosuppression after the antibiotic treatment did not lead to reactivation of bacteremia. Fine needle aspirates of different organs and bone marrow collected before and after immunosuppression were PCR-negative. Overall, 5 cats cleared bacteremia with doxycycline alone (showing lower bacterial loads at the treatment start), while 10 cats needed to be switched to marbofloxacin. Based on our results, we recommend doxycycline treatment (10 mg/kg up to 28 days) for clearance of M. haemofelis infection and monitoring bacterial loads by real-time PCR. Only if bacteremia persists or reoccurs, antibiotic treatment should be switched to marbofloxacin (2 mg/kg sid for 14 days).

Passive immunization does not provide protection against experimental infection with Mycoplasma haemofelis.

Mycoplasma haemofelis (Mhf) is the most pathogenic feline hemotropic mycoplasma. Cats infected with Mhf that clear bacteremia are protected from Mhf reinfection, but the mechanisms of protective immunity are unresolved. In the present study we investigated whether the passive transfer of antibodies from Mhf-recovered cats to naïve recipient cats provided protection against bacteremia and clinical disease following homologous challenge with Mhf; moreover, we characterized the immune response in the recipient cats. Ten specified pathogen-free (SPF) cats were transfused with pooled plasma from cats that had cleared Mhf bacteremia; five control cats received plasma from naïve SPF cats. After homologous challenge with Mhf, cats were monitored for 100 days using quantitative PCR, hematology, blood biochemistry, Coombs testing, flow cytometry, DnaK ELISA, and red blood cell (RBC) osmotic fragility (OF) measurement. Passively immunized cats were not protected against Mhf infection but, compared to control cats, showed significantly higher RBC OF and B lymphocyte (CD45R/B220(+)) counts and occasionally higher lymphocyte, monocyte and activated CD4(+) T lymphocyte (CD4(+)CD25(+)) counts; they also showed higher bilirubin, total protein and globulin levels compared to those of control cats. At times of peak bacteremia, a decrease in eosinophils and lymphocytes, as well as subsets thereof (B lymphocytes and CD5(+), CD4(+) and CD8(+) T lymphocytes), and an increase in monocytes were particularly significant in the passively immunized cats. In conclusion, passive immunization does not prevent bacteremia and clinical disease following homologous challenge with Mhf, but enhances RBC osmotic fragility and induces a pronounced immune response.

Effects of contrast medium injection technique on attenuation values of adrenal glands in healthy dogs during contrast-enhanced computed tomography.

OBJECTIVE: To assess the effects of 3 contrast medium injection techniques on attenuation values for canine adrenal glands during contrast-enhanced CT. ANIMALS: 9 healthy Beagles. PROCEDURES: 3 protocols were evaluated in a randomized cross-over design study: 700 mg of iodine/kg at a constant injection rate over 20 seconds (full-dose constant rate), the same dose at a rate following an exponential decay curve over 20 seconds (full-dose decelerated rate), and 350 mg of iodine/kg at a constant injection rate over 10 seconds (half-dose constant rate). Multislice CT images were obtained before and at predetermined time points after the start of contrast medium injection. RESULTS: Median peak attenuation values were 129, 133, and 87 Hounsfield units with the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injection protocols, respectively. Peak attenuation differed significantly between the full-dose constant rate and half-dose constant rate injection protocols and between the full-dose decelerated rate and half-dose constant rate injection protocols. Median time to peak attenuation did not differ significantly among injection methods and was 30, 23, and 15 seconds for the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injections, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The dose of contrast medium and the timing of postinjection CT scanning were main determinants of peak attenuation for adrenal glands in healthy dogs; effects of the 3 injection protocols on attenuation were minor. The exponentially decelerated injection method was subjectively complex. A constant injection protocol delivering 700 mg of iodine/kg over 20 seconds, with scans obtained approximately 30 seconds after starting contrast medium injection, provided images with maximum adrenal gland attenuation values.

Retroviral DNA--the silent winner: blood transfusion containing latent feline leukemia provirus causes infection and disease in naïve recipient cats.

BACKGROUND: The feline leukemia virus (FeLV) is a gamma-retrovirus of domestic cats that was discovered half a century ago. Cats that are infected with FeLV may develop a progressive infection resulting in persistent viremia, immunodeficiency, tumors, anemia and death. A significant number of cats mount a protective immune response that suppresses viremia; these cats develop a regressive infection characterized by the absence of viral replication and the presence of low levels of proviral DNA. The biological importance of these latter provirus carriers is largely unknown. RESULTS: Here, we demonstrate that ten cats that received a transfusion of blood from aviremic provirus carriers developed active FeLV infections, some with a progressive outcome and the development of fatal FeLV-associated disease. The infection outcome, disease spectrum and evolution into FeLV-C in one cat mirrored those of natural infection. Two cats developed persistent antigenemia; six cats were transiently antigenemic. Reactivation of infection occurred in some cats. One recipient developed non-regenerative anemia associated with FeLV-C, and four others developed a T-cell lymphoma, one with secondary lymphoblastic leukemia. Five of the ten recipient cats received provirus-positive aviremic blood, whereas the other five received provirus- and viral RNA-positive but aviremic blood. Notably, the cats that received blood containing only proviral DNA exhibited a later onset but graver outcome of FeLV infection than the cats that were transfused with blood containing proviral DNA and viral RNA. Leukocyte counts and cytokine analyses indicated that the immune system of the latter cats reacted quicker and more efficiently. CONCLUSIONS: Our results underline the biological and epidemiological relevance of FeLV provirus carriers and the risk of inadvertent FeLV transmission via blood transfusion and demonstrate the replication capacity of proviral DNA if uncontrolled by the immune system. Our results have implications not only for veterinary medicine, such as the requirement for testing blood donors and blood products for FeLV provirus by sensitive polymerase chain reaction, but are also of general interest by revealing the importance of latent retroviral DNA in infected hosts. When aiming to eliminate a retroviral infection from a population, provirus carriers must be considered.

Feline calicivirus and other respiratory pathogens in cats with Feline calicivirus-related symptoms and in clinically healthy cats in Switzerland.

BACKGROUND: Cats with feline calicivirus (FCV)-related symptoms are commonly presented to veterinary practitioners. Various clinical manifestations have been attributed to FCV, i.e. upper respiratory tract disease (URTD), oral ulcerations, gingivostomatitis, limping syndrome and virulent systemic disease. Additionally, healthy cats can shed FCV. The aims of this study were 1) to investigate the frequency of FCV in cats with FCV-related symptoms and in healthy cats in Switzerland, 2) to assess risk and protective factors for infection, such as signalment, housing conditions, vaccination, and co-infection with URTD-associated pathogens, and 3) to address the association between clinical symptoms and FCV infection. RESULTS: Oropharyngeal, nasal and conjunctival swabs were collected in 24 veterinary practices from 200 FCV-suspect and 100 healthy cats originating from 19 cantons of Switzerland. The samples were tested for FCV using virus isolation and reverse-transcription real-time quantitative polymerase chain reaction (qPCR) and for feline herpesvirus-1 (FHV-1), Mycoplasma felis, Chlamydophila felis, Bordetella bronchiseptica using real-time qPCR. Within the two populations (FCV-suspect/healthy), the observed PCR prevalences were: FCV 45%/8%, FHV-1 20%/9%, C. felis 8%/1%, B. bronchiseptica 4%/2%, M. felis 47%/31% and any co-infections thereof 40%/14%. Based on multivariable regression models amongst FCV-suspect cats (odds ratio [95% confidence interval]), co-infection with M. felis (1.75 [0.97; 3.14]), group housing (2.11 [1.02; 4.34]) and intact reproductive status (1.80 [0.99; 3.28]) were found to be risk factors for FCV infection. In healthy cats, intact reproductive status (22.2 [1.85; 266.7]) and group housing (46.4 [5.70; 377.7]) were found to be associated with FCV infection. Based on an univariable approach, FCV-suspect cats were found to be significantly less often FCV-positive when vaccinated (0.48 [0.24; 0.94]). Oral ulcerations, salivation, gingivitis and stomatitis, but not classical signs of URTD were significantly associated with FCV infection (all p < 0.001). CONCLUSIONS: FCV was detected in less than half of the cats that were judged FCV-suspect by veterinary practitioners. For a clinical diagnosis, FCV-related symptoms should be revisited. FCV infection was present in some healthy cats, underlining the importance of asymptomatic carriers in FCV epidemiology. To reduce FCV-related problems in multi-cat environments, reduction of group size in addition to the generally recommended vaccination are advocated.

Lack of cross-protection against Mycoplasma haemofelis infection and signs of enhancement in "Candidatus Mycoplasma turicensis"-recovered cats.

"Mycoplasma haemofelis" and "Candidatus Mycoplasma turicensis" are feline hemoplasmas that induce hemolytic anemia. Protection from homologous re-challenge was recently demonstrated in cats recovered from primary infection. Here, we determined if cats recovered from "Cand. M. turicensis" infection were protected against infections with the more pathogenic M. haemofelis. Ten specified pathogen-free cats were exposed to M. haemofelis. Five of the ten cats had recovered from "Cand. M. turicensis" bacteremia (group A), and five cats were naïve controls (group B). No cross-protection was observed. By contrast, the "Cand. M. turicensis"-recovered cats displayed faster M. haemofelis infection onset (earlier PCR-positive and anemic) than the controls. No "Cand. M. turicensis" was detected in any cat. M. haemofelis shedding was observed in saliva, feces and urine. In both groups, evidence of a Th1 response was observed (high IFN-γ, low IL-4), but IL-10 levels were also high. In group A, total, CD4+ and CD8+ T cells increased within days after M. haemofelis exposure. At times of maximal bacteremia, macrocytic hypochromic anemia, neutropenia, monocytosis and a decrease in leukocyte, eosinophil, and lymphocyte counts and subsets thereof (B- and T-cells, CD4+, CD8+ and CD4+CD25+ cells) were particularly significant in group A. Moreover, an increase in protein concentrations, hypoalbuminemia and a polyclonal hypergammaglobulinemia were observed. Five of ten M. haemofelis-infected cats subsequently cleared bacteremia without antibiotic treatment. In conclusion, the study suggests that a previous hemoplasma infection, even when the cat has ostensibly recovered, may influence subsequent infections, lead to an enhancement phenomenon and other differences in infection kinetics.

Detemir insulin for the treatment of diabetes mellitus in dogs.

OBJECTIVE: To investigate the effects of insulin detemir in dogs with diabetes mellitus. DESIGN: Prospective, uncontrolled clinical trial. ANIMALS: 10 client-owned dogs with naturally occurring diabetes mellitus. PROCEDURES: Dogs were treated with insulin detemir SC every 12 hours for 6 months. Follow-up evaluations were done at 1, 2, 4, 12, and 24 weeks and included evaluation of clinical signs and measurement of blood glucose concentration curves and serum fructosamine concentrations. RESULTS: Insulin detemir administration resulted in a significant decrease in blood glucose and serum fructosamine concentrations at 6 months, compared with pretreatment values. Median insulin dosage at the end of the study was 0.12 U/kg (0.055 U/lb; range, 0.05 to 0.34 U/kg [0.023 to 0.155 U/lb], SC, q 12 h). Hypoglycemia was identified in 22% (10/45) of the blood glucose concentration curves, and 6 episodes of clinical hypoglycemia in 4 dogs were recorded. A subjective improvement in clinical signs was observed in all dogs during the 6-month study period. On the basis of clinical signs and blood glucose concentration curves, efficacy of insulin detemir at the end of the study was considered good in 5 dogs, moderate in 3, and poor in 2. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that SC injection of insulin detemir every 12 hours may be a viable treatment for diabetes mellitus in dogs. Insulin detemir dosages were lower than reported dosages of other insulin types needed to maintain glycemic control, suggesting that insulin detemir should be used with caution, especially in small dogs.

No benefit of therapeutic vaccination in clinically healthy cats persistently infected with feline leukemia virus.

Therapeutic vaccinations have a potential application in infections where no curative treatment is available. In contrast to HIV, efficacious vaccines for a cat retrovirus, feline leukemia virus (FeLV), are commercially available. However, the infection is still prevalent, and no effective treatment of the infection is known. By vaccinating persistently FeLV-infected cats and presenting FeLV antigens to the immune system of the host, e.g., in the form of recombinant and/or adjuvanted antigens, we intended to shift the balance toward an advantage of the host so that persistent infection could be overcome by the infected cat. Two commercially available FeLV vaccines efficacious in protecting naïve cats from FeLV infection were tested in six experimentally and persistently FeLV-infected cats: first, a canarypox-vectored vaccine, and second, an adjuvanted, recombinant envelope vaccine was repeatedly administered with the aim to stimulate the immune system. No beneficial effects on p27 antigen and plasma viral RNA loads, anti-FeLV antibodies, or life expectancy of the cats were detected. The cats were unable to overcome or decrease viremia. Some cats developed antibodies to FeLV antigens although not protective. Thus, we cannot recommend vaccinating persistently FeLV-infected cats as a means of improving their FeLV status, quality of life or life expectancy. We suggest testing of all cats for FeLV infection prior to FeLV vaccination.