Histological and immunohistochemical features suggesting aetiological differences in lymph node and (muco)cutaneous feline tuberculosis lesions.

OBJECTIVES: To identify and describe histological and immunohistochemical criteria that may differentiate between skin and lymph node lesions associated with Mycobacterium (M.) bovis and M. microti in a diagnostic pathology setting. MATERIALS AND METHODS: Archived skin and lymph node biopsies of tuberculous lesions were stained with haematoxylin and eosin, Ziehl-Neelsen and Masson's Trichrome. Immunohistochemistry was performed to detect the expression of calprotectin, CD3 and Pax5. Samples were scored for histological parameters (i.e. granulomas with central necrosis versus small granulomas without central necrosis, percentage necrosis and/or multinucleated giant cells), number of acid-fast bacilli (bacterial index) and lesion percentage of fibrosis and positive immunohistochemical staining. RESULTS: Twenty-two samples were examined (M. bovis n=11, M. microti n=11). When controlling for age, gender and tissue, feline M. bovis-associated lesions more often featured large multi-layered granulomas with central necrosis. Conversely, this presentation was infrequent in feline M. microti-associated lesions, where small granulomas without central necrosis predominated. The presence of an outer fibrous capsule was variable in both groups, as was the bacterial index. There were no differences in intralesional expression of immunohistochemical markers. CLINICAL SIGNIFICANCE: Differences in the histological appearance of skin and lymph node lesions may help to infer feline infection with either M. bovis or M. microti at an earlier stage when investigating these cases, informing clinicians of the potential zoonotic risk. Importantly, cases of tuberculosis can present with numerous acid-fast bacilli. This implies that a high bacterial index does not infer infection with non-zoonotic non-tuberculous mycobacteria.

Cytokine and Chemokine Concentrations as Biomarkers of Feline Mycobacteriosis.

Mycobacteriosis is an emerging zoonotic disease of domestic cats and timely, accurate diagnosis is currently challenging. To identify differential cytokine/chemokine concentrations in serum/plasma of cats, which could be diagnostic biomarkers of infection we analysed plasma/serum from 116 mycobacteria-infected cats, 16 healthy controls and six cats hospitalised for unrelated reasons was analysed using the Milliplex MAP Feline Cytokine Magnetic Bead multiplex assay. Three cytokines; sFAS, IL-13 and IL-4 were reduced while seven; GM-CSF, IL-2, PDGF-BB, IL-8, KC, RANTES and TNF-α were elevated in mycobacteria-infected cats compared to healthy controls. However, IL-8 and KC concentrations were not significantly different from cats hospitalised for other reasons. Elevations in TNF-α and PDGF-BB may have potential to identify M. bovis and M. microti infected cats specifically while GM-CSF, IL-2 and FLT3L were increased in MTBC infected cats. This study demonstrates potential use of feline tuberculosis as a spontaneously occurring model of this significant human disease. Cytokine profiling has clear diagnostic potential for mycobacteriosis of cats and could be used discriminate tuberculous from non-tuberculous disease to rapidly inform on zoonotic risk. Future work should focus on the in-field utility of these findings to establish diagnostic sensitivity and specificity of these markers.

Serum Cardiac Troponin I concentrations in cats with anaemia - a preliminary, single-centre observational study.

OBJECTIVES: A range of cardiovascular abnormalities have been associated with anaemia. However, it remains unclear whether anaemia is associated with cardiac myocyte damage in cats. The aim of this study was to assess if cats with anaemia have an increased prevalence of cardiac myocyte damage, as assessed by serum concentrations of cardiac troponin I, compared to non-anaemic, ill cats. METHODS: Serum cardiac troponin I concentrations were measured in 18 anaemic cats and in 31 non-anaemic, ill cats with non-primary cardiac, non-renal and non-primary haematological disorders. RESULTS: The serum cardiac troponin I concentrations in the anaemic group (0·43 ng/mL) were significantly higher (P=0·0002) than in the non-anaemic ill group (0·04 ng/mL). Using a cut-off of less than 0·16 ng/mL, 12 of the 18 anaemic cats had an increased serum cardiac troponin I concentration, which was significantly higher (P=0·005) than the non-anaemic ill cats (7 of 31 cats). CLINICAL SIGNIFICANCE: Serum cardiac troponin I concentrations were higher in cats with anaemia in this study. Further studies are required to establish whether the anaemia or other confounding factors is the cause of the increased serum cardiac troponin I concentrations.

Cats with inflammatory bowel disease and intestinal small cell lymphoma have low serum concentrations of 25-hydroxyvitamin D.

BACKGROUND: Inflammatory bowel disease (IBD) and intestinal small cell lymphoma (ISCL) are common diseases in cats. The prevalence of alterations in the serum concentrations of fat soluble vitamins, such as vitamin D, in cats with IBD and ISCL is unknown. HYPOTHESIS/OBJECTIVES: The objective of this study was to measure serum 25 hydroxyvitamin D (25[OH]D) concentrations in cats with IBD or ISCL. Serum 25(OH)D also was measured in healthy cats, and in hospitalized ill cats with nongastrointestinal diseases. ANIMALS: Eighty-four cats were included in the study: 23 in the healthy group, 41 in the hospitalized ill group, and 20 in the IBD/ISCL group. METHODS: Retrospective study. Serum samples for vitamin D analysis were frozen at -20°C until serum 25(OH)D was measured by high-performance liquid chromatography (HPLC). RESULTS: Although there was overlap in serum 25(OH)D concentrations among the 3 groups, serum 25(OH)D concentrations were significantly lower in the cats with IBD or ISCL compared to healthy cats (P < .0001) and hospitalized ill cats (P = .014). In the IBD/ISCL group, there was a significant moderate positive correlation between serum albumin and 25(OH)D concentrations (r = 0.58, P = .018). CONCLUSION AND CLINICAL IMPORTANCE: The median serum concentration of 25(OH)D was significantly lower in cats with IBD/ISCL than in healthy cats and in hospitalized ill cats. Additional studies are required to elucidate the mechanism of hypovitaminosis D in cats with gastrointestinal diseases, to define the best management strategy to treat this complication, and to investigate its potential prognostic implications.

Incidence of mycobacterial infections in cats in Great Britain: estimate from feline tissue samples submitted to diagnostic laboratories.

The aim of this study was to estimate the incidence of mycobacterial infections in cats in Great Britain (GB). This was performed using the proxy measure of feline tissue samples submitted to diagnostic laboratories in GB that were found to have histopathological changes typical of mycobacterial infection ('MYC'). Sixteen primary diagnostic laboratories were asked for information on the number of feline samples submitted in 2009, the number with MYC, the number undergoing Ziehl-Neelsen (ZN) staining and, for comparison, the number diagnosed with lymphoma. Eight laboratories provided full data for the whole year: 11,782 samples; lymphoma 3.2% (mean, 95% CI: 2.89, 3.5), MYC 1.16% (0.98; 1.37) and ZN-positive 0.31% (0.22; 0.43). Data on 1569 samples from seven laboratories that provided partial data on samples for the whole year revealed similar results, although all changes were more frequent: lymphoma 5.42% (4.35; 6.66), MYC 2.36% (1.66; 3.23) and ZN-positive 0.77% (0.40; 1.33). One laboratory only provided data for part of the year (4.5 months), reporting all three types of histopathology less frequently: 18,232 samples; lymphoma 0.2% (0.18; 0.32), MYC 0.07% (0.04; 0.12) and ZN-positive 0.05% (0.02; 0.09). The reasons for low reporting rates in this high-throughput laboratory are unclear. In total, 187 samples were reported as having MYC. Five Reference laboratories were also contacted, reporting 174 feline tissue submissions in 2009, with mycobacteria being cultured from 90. The study shows that MYC are frequently reported in tissue samples from cats in GB, being reported in ~1% of samples, with confirmation as ZN-positive in ~0.3%. Lymphoma is recognized as a common disease in cats, being seen in ~3% of samples in this study. When compared against MYC, lymphoma was reported only twice as frequently. This confirms that far from being rare, clinically significant mycobacterial infections occur commonly in cats in GB.

Comparison of a digital and an optical analogue hand-held refractometer for the measurement of canine urine specific gravity.

Urine specific gravity (USG) is used clinically as a measure of urine concentration, and is routinely assessed by refractometry. A comparison between optical analogue and digital refractometers for evaluation of canine urine has not been reported. The aim of this study was to compare a digital and an optical analogue hand-held refractometer for the measurement of canine USG, and to assess correlation with urine osmolality. Prospective study. Free-catch urine samples were collected from 285 hospitalised adult dogs, and paired USG readings were obtained with a digital and an optical analogue refractometer. In 50 dogs, urine osmolality was also measured using a freezing point depression osmometer. There was a small but statistically significant difference between the two refractometers (P<0.001), with the optical analogue refractometer reading higher than the digital refractometer (mean difference 0.0006, sd 0.0012). Paired refractometer measurements varied by <0.002 in 91.5 per cent of cases. The optical analogue and digital refractometer readings showed excellent correlation with osmolality (r=0.980 and r=0.977, respectively, P<0.001 in both cases). Despite statistical significance, the difference between the two refractometers is unlikely to be clinically significant. Both instruments provide an accurate assessment of USG in dogs.

Domesticated cats with active mycobacteria infections have low serum vitamin D (25(OH)D) concentrations.

Vitamin D insufficiency is regularly observed in human patients with tuberculosis but it is unknown if spontaneous mycobacteria infections in other species are associated with suboptimal vitamin D status. Serum 25 hydroxyvitamin D (25(OH)D) concentrations were significantly lower in cats with mycobacteriosis than in healthy cats (P < 0.001).

Evaluation of suicide awareness programmes delivered to veterinary undergraduates and academic staff.

In an effort to increase suicide awareness skills among veterinary undergraduates, a three-hour suicide awareness workshop (safeTALK) was delivered to third-year Royal (Dick) School of Veterinary Studies undergraduates as part of their professional development curriculum. Students were able to opt out of the session by contacting the course organisers. A total of 26 of 151 (17 per cent) third-year students attended the workshop, and 17 completed a feedback questionnaire. The vast majority of the students reported that after completing the workshop they were more likely or much more likely to recognise the signs of a person at risk of suicide, approach a person at risk of suicide, ask a person about suicide, and connect a person at risk of suicide with help. Five veterinary academics attended a two-day Applied Suicide Intervention Skills Training (ASIST) course, and all reported that the course was effective in improving suicide awareness and intervention skills.

Cognitive dysfunction and the neurobiology of ageing in cats.

With improvements in nutrition and veterinary medicine the life expectancy of pet cats is increasing. Accompanying this growing geriatric population there are increasing numbers of cats with signs of apparent senility. A recent study suggests that 28 per cent of pet cats aged 11 to 14 years develop at least one geriatric onset behavioural problem, and this increases to over 50 per cent for cats of 15 years of age or older. While behavioural changes may result from systemic illness, organic brain disease or true behavioural problems, the possibility of age-related cognitive dysfunction is often overlooked. Studies have revealed a number of changes in the brains of geriatric cats that showed signs of cognitive dysfunction, and potential causes include vascular insufficiency leading to hypoxia, increased free radical damage and the deposition of beta-amyloid plaques and/or the modification of other proteins. By recognising the importance of behavioural changes in old cats, investigating them fully for potentially treatable medical conditions, and instigating dietary and environmental modifications to meet their changing needs, we can make the lives of our geriatric cats much more comfortable and rewarding.

Factors associated with upper respiratory tract disease caused by feline herpesvirus, feline calicivirus, Chlamydophila felis and Bordetella bronchiseptica in cats: experience from 218 European catteries.

A full history of the management practices and the prevalence of upper respiratory tract disease (URTD) at 218 rescue shelters, breeding establishments and private households with five or more cats was recorded. Oropharyngeal and conjunctival swabs and blood samples were taken from 1748 cats. The prevalences of feline herpesvirus (FHV), feline calicivirus (FCV), Chlamydophila felis and Bordetella bronchiseptica were determined by PCR on swab samples. An ELISA was applied to determine the prevalence of antibodies to B. bronchiseptica. The rates of detection by PCR of each pathogen in the cats in catteries with and without ongoing URTD were, respectively, FHV 16 per cent and 8 per cent; FCV 47 per cent and 29 per cent; C. felis 10 per cent and 3 per cent; and B. bronchiseptica 5 per cent and 1.3 per cent; the seroprevalences of B. bronchiseptica were 61 per cent and 41 per cent, respectively. There was evidence that FHV, FCV and B. bronchiseptica played a role in URTD. The risk factors associated with the disease were less than excellent hygiene, contact with dogs with URTD, and larger numbers of cats in the cattery or household.

Oral glucosamine and the management of feline idiopathic cystitis.

Oral glucosamine was compared to a placebo for the management of cats with feline idiopathic cystitis (FIC) in a randomised, double-blinded, placebo-controlled, study. Forty cats with a history of recurrent cystitis due to FIC were divided into two groups and treated daily per os with either 125 mg N-acetyl glucosamine or a placebo for six months. Owners graded their cats' clinical signs at the beginning and end of the study, and kept daily diaries documenting signs of cystitis using visual analogue scales. Further episodes of cystitis were seen in 26 (65%) of the cats during the study. Affected cats experienced a mean of five recurrences (range 1-19) with each recurrence lasting a mean of four days (range 1-64 days). There were no significant differences between the two groups when considering the owners assessments of the mean health score (P>0.5), the average monthly clinical score (P=0.22) or the average number of days with clinical signs (P=0.28). Two cats suffered from such severe recurrent urethral obstruction that they were euthanased; they were both in the placebo group. Compared to the start of the study the majority of cats in both groups improved significantly (P<0.001) (mean health score of each group at the start was 0.5+/-SD 0.5, compared to glucosamine 4.4+/-0.7 and placebo 3.9+/-1.6 at the end). This is believed to have occurred because the owners of 36 of the 40 cats (90%) started feeding more canned cat food. The urine specific gravity at the start of the trial was significantly higher (mean 1.050+/-SD 1.007) than when reassessed one month later (1.036+/-1.010, P<0.01).

A pilot study using synthetic feline facial pheromone for the management of feline idiopathic cystitis.

Synthetic feline facial pheromone (FFP) (Feliway; Ceva Animal Health) was assessed for the management of cats with recurrent feline idiopathic cystitis (FIC). Nine of 12 cats completed the randomised, double-blinded, placebo-controlled, crossover pilot study. They had their environment treated daily with either FFP or placebo for 2 months, after which time the treatment groups were reversed. Owners used visual analogue scales to define the severity of their cat's clinical signs and behavioural changes. Five (56%) of the owners stated that their cat's overall health was better when they were using FFP. Four (44%) of the owners noticed no difference between when using the FFP and when using the placebo. While there were no statistical differences between the two treatment groups there was a trend for the cats exposed to FFP to show fewer days with clinical signs of cystitis (FFP total, mean per cat+/-standard deviation, 30, 4.3+/-6.7; placebo 69, 9.9+/-19.1), a lower overall clinical score (1667, 238+/-476; 2009, 287+/-425), a reduced number of episodes of cystitis (9, 1.3+/-2.0; 10, 1.4+/-2.1) and reduced negative behavioural traits (e.g., less aggression and fear) (-128, -18.3+/-65.8; -73, -10.4+/-35.1).

High viral loads despite absence of clinical and pathological findings in cats experimentally infected with feline coronavirus (FCoV) type I and in naturally FCoV-infected cats.

Specified pathogen-free cats were naturally infected with FCoV or experimentally infected with FCoV type I. Seroconversion was determined and the course of infection was monitored by measuring the FCoV loads in faeces, whole blood, plasma and/or monocytes. Tissue samples collected at necropsy were examined for viral load and histopathological changes. Experimentally infected animals started shedding virus as soon as 2 days after infection. They generally displayed the highest viral loads in colon, ileum and mesenteric lymph nodes. Seroconversion occurred 3-4 weeks post infection. Naturally infected cats were positive for FCoV antibodies and monocyte-associated FCoV viraemia prior to death. At necropsy, most animals tested positive for viral shedding and FCoV RNA was found in spleen, mesenteric lymph nodes and bone marrow. Both experimentally and naturally infected cats remained clinically healthy. Pathological findings were restricted to generalized lymphatic hyperplasia. These findings demonstrate the presence of systemic FCoV infection with high viral loads in the absence of clinical and pathological signs.

A study of environmental and behavioural factors that may be associated with feline idiopathic cystitis.

The cause of cystitis in many cats remains unknown. The aim of this study was to determine whether or not any environmental or behavioural factors, particularly those that could be considered potentially stressful, were associated with feline idiopathic cystitis (FIC). The questionnaire-based study involved comparing 31 cats with FIC to 24 cats in the same households that did not have cystitis. They were also compared with a control population of 125 clinically healthy cats. Compared with the live-in controls and the control population, the cats with FIC were significantly more likely to be male, overweight and pedigree. Several stress factors were found to be associated with FIC. The factor that stood out most prominently was living with another cat with which there was conflict. The findings support the hypothesis that stress may be implicated in some cases of FIC.

Opportunistic mycobacterial granuloma in a cat associated with a member of the Mycobacterium terrae complex.

An 18-month-old domestic short-haired neutered male cat presented with a nodular dermal thickening on a digit. Biopsy demonstrated pyogranulomatous inflammation with moderately frequent acid-fast bacilli. A member of theMycobacterium terrae complex was isolated. There was no evidence of systemic involvement. Treatment was initiated with enrofloxacin, rifampicin and clarithromycin. After 2 months there was no longer any clinically apparent dermal thickening. Treatment was continued for a further 3 months using enrofloxacin and rifampicin.