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.

Detection of feline coronaviruses by culture and reverse transcriptase-polymerase chain reaction of blood samples from healthy cats and cats with clinical feline infectious peritonitis.

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the detection of the feline coronavirus (FCoV) genome and a co-cultivation method for the isolation of field strains of FCoV are described. Using the RT-PCR assay to assess blood samples from cats with feline infectious peritonitis (FIP) (n = 47) and healthy cats from households with endemic FCoV (n = 69) it was shown that approximately 80% of the cats were viraemic, irrespective of their health status. It was also shown that, over a 12-month period, a similar percentage of healthy cats remained viraemic, and that the presence of viraemia did not appear to predispose the cats to the development of FIP. The co-cultivation system proved to be a suitable method for the culture of field strains of FCoV from blood samples, so long as the cultures were maintained for at least 4 weeks. Using this system, followed by the RT-PCR, viraemia was detected as frequently as by RT-PCR on RNA extracted directly from peripheral blood mononuclear cells.

Antibody and cytokine responses in kittens during the development of feline infectious peritonitis (FIP).

Two recombinant FIPV spike proteins were assessed for their immunogenic properties in 8-week-old kittens, which were then challenged intranasally with FIPV 79-1146. Humoral responses were assessed by ELISA and serum neutralisation test. Changes in PBMC cytokine mRNA levels were detected by a reverse transcription, semiquantitative polymerase chain reaction assay (RT-sqPCR), assessing IL-2, IL-4, IL-6, IL-10, IL-12 and IFNgamma. All of the kittens developed clinical signs typical of FIP, which were confirmed on gross post mortem examination. The recombinant proteins induced little or no specific antibody response prior to challenge, and failed to alter the course of disease compared to controls. One week after virus challenge, the stimulated PBMCs showed small increases in the expression of IL-6 and IFNgamma mRNA, which correlated with a transient pyrexia. After this time expression of IL-6 mRNA remained unaltered but, as FIP developed, mRNA levels of IL-2, IL-4, IL-10, IL-12 and IFNgamma became markedly depressed.

Desquamative form of cryptogenic fibrosing alveolitis in a cat.

Bronchopulmonary disease is not uncommon in cats, many cases falling into the categories of chronic bronchitis and the "feline asthma syndrome". We report a case of chronic bronchopulmonary disease in an adult cat, which was initially diagnosed as chronic bronchitis. Failure to respond to appropriate therapy led to euthanasia. At necropsy, the lungs exhibited multifocal areas of consolidation, especially at the periphery of the diaphragmatic lobes. Histopathological examination revealed a striking variability of lesions, with interstitial fibrosis and intra-alveolar accumulations of macrophages in addition to alveolar epithelialization and smooth muscle hyperplasia. These changes were consistent with those described for the desquamative form of cryptogenic fibrosing alveolitis in human beings.

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).

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).

Successful treatment of uterine torsion in a cat with severe metabolic and haemostatic complications.

A peri-parturient fifteen-month-old female Maine Coon cat was presented with extreme weakness and depression, profound hypovolaemia and hypothermia. Severe hyperkalaemia, hyponatraemia and anaemia were detected. Disseminated intravascular coagulation was suspected due to marked prolongation of activated partial thromboplastin time. Uterine torsion was diagnosed at exploratory laparotomy. The cat made a full recovery following ovariohysterectomy and intensive supportive therapy.

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.

Immune-mediated haemolytic anaemia in two sibling cats associated with multicentric lymphoblastic infiltration.

Immune-mediated haemolytic anaemia associated with multicentric lymphoblastic infiltration is reported in two sibling cats. Both cats presented at under 16 months of age with clinical signs of acute anaemia. In each case there was autoagglutination, a positive Coombs' test and the anaemia was regenerative. At presentation, both cats were negative for FeLV antigen. In each case, the disease proved fatal within 2 months of the initial diagnosis. In both cases, T-lymphoblastic infiltration of bone marrow, liver and spleen was found at post-mortem examination.

Feline dystocia: prevalence, and association with cranial conformation and breed.

The litter prevalence of feline dystocia was investigated using a questionnaire survey of cat breeders. Information was obtained on 2928 litters, from 735 queens. Dystocia was reported to have occurred in 5.8 per cent of litters. The level of dystocia in individual breeds ranged from 0.4 per cent of litters born in a large colony of cats of mixed breeding, to 18.2 per cent of litters in the Devon rex. Pedigree litters were at significantly higher risk than litters of cats of mixed breeding (odds ratio: 22.6). Relatively high levels of dystocia were identified in Siamese-type, Persian and Devon rex litters, whereas cats of mixed breeding showed a relatively low litter prevalence. Dolicocephalic and brachycephalic types were found to have significantly higher levels of dystocia than mesocephalic cats.

Feline tuberculosis: a literature review and discussion of 19 cases caused by an unusual mycobacterial variant.

The literature relating to feline mycobacterial disease is reviewed and 19 cats with tuberculosis caused by a previously unknown strain of mycobacterium are discussed. The bacteria were found to have characteristics between those of Mycobacterium tuberculosis and M bovis. The paper considers the clinical signs, epidemiology and diagnosis of the cases, and discusses the possible origins of the organism, treatment regimens and zoonotic potential.

Transient hyperlipidaemia and anaemia in kittens.

Severe fasting hypertriglyceridaemia (5 to 126 mmol/litre) and anaemia (packed cell volume < 11 per cent) was observed in 12 litters of kittens around the time of weaning; the entire litter was usually affected, with significant mortality. Lipid analysis revealed marked increases in chylomicrons and moderate increases in very low density lipoproteins. Supportive measures for the treatment of anaemia and weaning on to a low fat diet resulted in rapid resolution of the clinical signs, anaemia and hypertriglyceridaemia. On recovery, plasma was collected from kittens from five of the affected litters, plus a number of closely related cats and unrelated cats living in the same environment. The lipoprotein lipase (LPL) activity was mildly but significantly lower in the previously affected kittens, their parents and unaffected siblings, than in the unrelated cats. The cats had normal apolipoprotein C-II function, normal heparin binding activity and no evidence of a circulating inhibitor to LPL. They did not have the LPL gene mutation reported previously in LPL-deficient cats from New Zealand.

Natural Borna disease virus infection in cats in the United Kingdom.

Borna disease virus (BDV) is a novel RNA virus that has only recently been characterised and classified in a new virus family, Bornaviridae. The virus was detected in buffy coat cells from four of five cats with neurological disease and in the brains of five of 15 cats with nervous signs and of one of three cats with non-neurological disease. In a serosurvey of 111 cats the incidence of antibody to BDV in cats with neurological disease was higher than in cats with other types of disease, suggesting that the virus may play a role in nervous diseases of cats in the UK.

Priapism in seven cats.

Priapism (persistent and painful erection) is an uncommon disorder in cats and dogs. This report describes the clinical and pathological features of seven cases of priapism in cats. Six of the cases were Siamese cats, and in four of them the priapism developed after attempted mating with an oestrus female, despite three of them having been neutered. Five cats were treated by perineal urethrotomy, which was successful in four. In five of the six amputated specimens, thrombosis of the corpus cavenosum was evident.

Unusual metaphyseal disturbance in two kittens.

This report describes the presenting features, radiographic changes, biochemical alterations and clinical progress of two kittens, from separate litters, which were found to have a growth plate disturbance initially diagnosed and treated as vitamin D3-dependent rickets, but subsequently suspected to be a metaphyseal chondrodysplasia.

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.

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.

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.