Prevalence and risk factors for gingivitis in a cohort of UK companion cats aged up to 6 years.

OBJECTIVES: Prospectively collected data were used to estimate the prevalence of gingivitis in a cohort of companion cats aged up to 6 years and to investigate factors associated with the risk of gingivitis in cats aged 3 to 4 years. MATERIALS AND METHODS: Data were obtained from a longitudinal study of domestic cats (the Bristol Cats Study), using owner-completed questionnaires and veterinary surgeon-completed oral health scores. Prevalence estimates of veterinary-reported gingivitis for cats aged up to 6 years old (n = 1534) were calculated for different age groups. Cat signalment, diet and dental care were assessed for association with gingivitis in cats aged 3 to 4 years (n = 317) using univariable and multiple logistic regression. RESULTS: The prevalence of gingivitis increased with age and ranged from 24.5% (<12 months old) to 56.3% (5 to 6 years old). Odds of gingivitis in cats aged 3 to 4 years were higher in cats fed a wet only or mixed wet/dry diet compared to dry only (odds ratio: 2.7; 95% confidence interval: 1.4 to 5.1), cats not reported to hunt compared to reported hunters (odds ratio: 2.1; 95% confidence interval: 1.0 to 4.2), cats reported to dribble whilst being stroked at age 6 months compared to reported non-dribblers (odds ratio: 3.2; 95% confidence interval: 1.3 to 8.4) and cats with orange variants in their coat colour compared to non-orange cats (odds ratio: 2.3; 95% confidence interval: 1.0 to 5.3). CLINICAL SIGNIFICANCE: These results will help veterinary surgeons identify cats that may be at a greater risk of gingivitis and provide an evidence base to inform dietary and oral healthcare recommendations aimed at promoting gingival health in cats.

Survey of the characteristics of cats owned by households in the UK and factors affecting their neutered status.

Data were collected on 1260 cats owned by a random sample of UK households in 2007, by means of telephone questionnaires, which were completed by 33 per cent of the households contacted. Cats were owned by 26 per cent of these households, 42 per cent of which owned more than one cat. The owners of 622 female cats reported a total of 110 unplanned litters of kittens. Excluding cats with an unknown neutered status 92 per cent of the cats aged six months or more were neutered, but only 66 per cent of the cats aged six to 12 months were neutered. Multivariable logistic regression, based on data collected for one randomly selected cat aged four months or more in each cat-owning household, was used to identify factors affecting the cats' neutered status. Analysis of 48 sexually entire cats and 501 neutered cats showed that cats aged 10 months or more, with indoor access, that had been vaccinated within the last year or were currently registered with a veterinary practice, were more likely to be neutered than cats aged less than 10 months, without indoor access, that had been vaccinated more than one year ago or were not registered with a veterinary practice.

Is feline foamy virus really apathogenic?

Feline foamy virus (FFV) is a retrovirus commonly found in cats. It is generally thought to be apathogenic, making it a suitable candidate as a gene therapy vector. However, there have been reports of association of FFV with chronic progressive arthritis and a cofactor effect with feline immunodeficiency virus. This study investigated experimental FFV infection and whether this was associated with signs of disease. Eight young specific pathogen free cats were inoculated intramuscularly with FFV. The cats were examined twice weekly and blood and pharyngeal samples were taken. Haematology, biochemistry and FFV quantitative polymerase chain reaction (qPCR) were performed. Tissue samples were also collected throughout the six month period. FFV was initially detected by qPCR in the blood within the first two weeks of infection and viraemia persisted throughout the study. Two peaks of viraemia were observed, at day 20 (80-170FFU/ml blood) and day 155 (332-415FFU/ml blood). FFV was also consistently detected in oropharyngeal samples after day 36. Anti-FFV IgG was detected in all cats by ELISA; antibody levels had an early peak around day 35 and then increased again following the second rise in circulating viral load. All cats remained clinically normal, except for one cat with an unrelated gingivitis. None of the cats developed pyrexia. The biochemical profile and blood cell counts remained within normal limits except for one cat with a persistent eosinophilia. Initial fluctuations in white cell counts settled within three weeks and did not deviate outside of the normal ranges. All tissue samples contained FFV DNA; lymphoreticular tissues, salivary gland and lung had the highest viral loads. Although there were no gross pathological lesions on post mortem examination, histologically a mild glomerulonephritis and a moderate interstitial pneumonia were observed in all cats. We conclude that during the six month period of infection, although cats appeared clinically normal, histopathological changes were observed in the lungs and kidneys. Further investigation of the significance of these changes is warranted before FFV is developed as a vector for gene delivery.

Opinions of veterinarians about the age at which kittens should be neutered.

The mean age recommended by veterinary practices for neutering kittens is 22.6 weeks, with only 28 per cent of veterinarians considering it appropriate to neuter 12- to 16-week-old kittens. Multivariable logistic regression was used to identify variables associated with veterinarians' opinion that 12 to 16 weeks is an appropriate age at which to neuter kittens. Significant risk factors included time since graduation, perception of the problem of there being too many unwanted domestic cats and their practice's policy on the recommended neutering age. Veterinarians who thought that neutering eight- to 11-week-old rescue kittens before homing was justified and veterinarians who had neutered 12- to 16-week-old domestic kittens within the previous year were more likely to consider that neutering 12- to 16-week-old kittens was appropriate. Veterinarians who thought that surgical complications, anaesthetic complications and lower urinary tract disease were, or might be, more likely to occur in kittens neutered at 12 to 16 weeks than in those neutered at six months of age, were significantly less likely to think that neutering 12- to 16-week-old kittens was appropriate.

Risk factors for road traffic accidents in cats up to age 12†months that were registered between 2010 and 2013 with the UK pet cat cohort ('Bristol Cats').

Road traffic accidents (RTAs) are a common cause of death and injury in domestic cats, and a concern to many owners. This study assessed potential risk factors for RTAs in cats up to 12 months of age within a UK cat cohort known as 'The Bristol Cats study'. Data were obtained from three questionnaires, completed by cat owners when their cats were approximately 8-16 weeks old, 6 months old and 12 months old. Information was gathered regarding environmental conditions, cat characteristics and owner management factors. Univariable and multivariable logistic regression models were used to assess associations between these factors and RTAs. Of 1264 eligible study cats, 49 (3.9 per cent) had been involved in an RTA, of which 71.4 per cent (35/49) were known to result in fatal injuries. Rural locations were associated with a higher odds of RTAs than towns, cities or suburban locations. An increased odds of an RTA was also associated with cats that were reported by their owners to hunt at the roadside, as well as cats whose owners classified the road by their house as being a 'long straight section of road'. No significant associations were found between coat colour, breed, sex or neuter status and the odds of an RTA.

Early-life risk factors identified for owner-reported feline overweight and obesity at around two years of age.

Obesity is considered the second most common health problem in pet cats in developed countries. This study used prospective data from a longitudinal study of pet cats ('C.L.A.W.S.', www.bristol.ac.uk/vetscience/claws) to identify early-life risk factors for feline overweight/obesity occurring at around two years of age. Data were collected via five owner-completed questionnaires (for cats aged two-six months, six months, 12 months, 18 months and two years respectively) completed between May 2011 and April 2015. Owner-reported body condition scores (BCS) of cats at age two years, assessed using images from the 9-point BCS system (Laflamme, 1997), were categorised into a dichotomous variable: overweight/obese (BCS 6-9) and not overweight (BCS 1-5) and used as the dependent variable. Of the 375 cats with owner-reported BCS, 25.3% were overweight or obese at two years of age. Multivariable logistic regression models were built using stepwise forward-selection. To account for potential hierarchical clustering due to multi-cat households two-level random intercept models were considered but clustering had no impact on the analysis. Models were compared using Wald tests. Six factors were significantly associated with overweight/obesity at two years of age: being overweight or obese at one year of age (OR=10.6, 95%CI 4.4-25.3); owner belief that BCS 7 was the ideal weight (OR=33.2, 95%CI 8.5-129.4), or that BCS represented overweight cats but they would not be concerned if their cat were classified in this category (OR=2.7, 95%CI 1.2-6.2), at questionnaire five completion; vets advising owners that the cat should lose weight, or making no comment on their weight, between one and two years of age (OR=12.1, 95%CI 3.2-44.9 and OR=3.9, 95%CI 1.5-10.3 respectively); owners giving their cat treats when they "felt happy" with them at 18 months of age (OR=2.7, 95%CI 1.0 - 7.3); feeding ≥250g wet food daily between two and six months of age (OR=2.7, 95%CI 1.2-5.9), and feeding dry food as the only or major part (>50%) of the diet at two years of age (OR=2.1, 95%CI 1.0-4.2). These findings have the potential to reduce the current high prevalence of a widespread problem by informing preventive advice, and as such improving the health and welfare of pet cats.

Measurement of cytokine mRNA expression in intestinal biopsies of cats with inflammatory enteropathy using quantitative real-time RT-PCR.

Inflammatory bowel disease (IBD) is a common condition in cats characterised by infiltration of inflammatory cells into the intestinal mucosa. In this study, real-time reverse transcriptase polymerase chain reaction (RT-PCR) was used to quantify cytokine messenger RNA (mRNA) expression in intestinal biopsies from cats. Biopsies were collected from seven cats with chronic diarrhoea and histologically confirmed IBD, five cats with chronic diarrhoea due to non-IBD gastrointestinal (GI) disease, and nine clinically normal cats with or without subclinical inflammatory changes in small intestine. Real-time RT-PCR was developed for quantification of mRNA encoding interleukin (IL)-2, IL-4, IL-5, IL-6, IL-10, IL-12 (p35 and p40), IL-18, tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and transforming growth factor-beta (TGF-beta). Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as a 'housekeeper' gene. All real-time PCR efficiencies were>90% (range 90.4-102%) with correlation coefficients >0.99 (range 0.998-1). The results of the study were analyzed on the basis of either clinical presentation or histopathological evidence of intestinal inflammation. The former analysis showed that mRNA encoding IL-10 and TGF-beta (immunoregulatory cytokines), and IL-6, IL-18, TNF-alpha and IL-12 p40 (Th1 and pro-inflammatory cytokines) was significantly higher in clinically normal cats and cats with IBD when compared to cats with other GI diseases. IL-5 mRNA was significantly higher in cats with IBD compared to clinically normal cats. IL-2 mRNA was significantly lower in cats with non-IBD GI disease than in clinically normal cats. Analysis on the basis of histopathological change revealed that cats with intestinal inflammation had significantly more transcription of genes encoding IL-6, IL-10, IL-12p40, TNF-alpha and TGF-beta than those with normal intestinal morphology. The results suggest that immune dysregulation plays a role in feline IBD and that IBD in cats has a complicated pathogenesis with both pro-inflammatory and immunoregulatory features.

Immunohistochemical diagnosis of alimentary lymphomas and severe intestinal inflammation in cats.

Intestinal tissue samples were examined from 32 cats in which a histopathological diagnosis of alimentary lymphoma or multicentric lymphoma affecting the gastrointestinal tract had been made. These samples were re-evaluated histopathologically and serial sections were examined immunohistochemically with antisera specific for the lymphoid markers CD3, CD79a and BLA-36 and for class II molecules of the major histocompatability complex. The cats ranged in age from 4-16 years (median 10.5 years). The main presenting clinical signs were vomiting, diarrhoea and weight loss. The majority of alimentary lymphomas were of the B-cell type (n=15), whereas cases of T-cell lymphoma were fewer in number (n=8). Four cats had lymphoma of a mixed T-and B-cell phenotype. In five of the cats, immunohistochemistry suggested an inflammatory process, in contradiction to the original histopathological diagnosis of lymphoma. Immunolabelling would appear to be a useful adjunct to histopathology in classifying cases of feline alimentary lymphoma, and may help in distinguishing lymphoma from severe intestinal inflammation.

Preliminary study using an indirect ELISA for the detection of serum antibodies to Alternaria in domestic cats.

Alternaria is a saprophytic fungus that is widespread in the environment; it is an opportunistic pathogen and causes disease in human beings and domestic animals. Fungal spores gain entry to the host through skin lesions and cause slow-growing, soft to firm, subcutaneous swellings, either with or without ulcers. An indirect ELISA was developed for the detection of anti-Alternaria immunoglobulin G (IgG) antibodies in serum to determine the prevalence of Alternaria exposure in domestic cats. Fifty-two of 63 cats had detectable levels of anti-Alternaria IgG antibody. There were no correlations between the concentration of antibody and the sex, breed or living environment of the cats, but cats less than two years of age had significantly lower concentrations than older cats. The cats with disease caused by culture-confirmed Alternaria infections did not have significantly higher concentrations of antibody than the healthy cats or cats with other diseases.

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.

Assessing changes in the UK pet cat and dog populations: numbers and household ownership.

The main aim of this study was to replicate methodology used to estimate the size of the UK pet cat and dog populations in 2006 and the proportion of households owning cats/dogs in 2007, to produce updated data to compare trends in ownership and population sizes. A cross-sectional study design was used to collect telephone interview data from 3155 households in the UK. 2011 UK human census data were used to predict the size of the cat and dog populations owned by households in the UK in 2011. Of the households, 23 per cent (714/3155) owned one or more cats and 30 per cent (940/3155) owned one or more dogs. There was some overlap in pet ownership with 7 per cent (210/3155) of households owning both one or more cats and one or more dogs. There was a small but significant decrease in the proportion of households that owned one or more cats in 2011 compared with 2007, with no change in the proportion owning dogs. However, overall, the total number of cats and dogs that were estimated to be owned by UK households did not change significantly between 2006 and 2011. The estimated size (and 95% CIs) of the pet cat and dog populations in the UK in 2011 was 10,114,764 cats (9,138,603-11,090,924) and 11,599,824 dogs (10,708,070-12,491,578).

Impaired T-cell priming and proliferation in cats infected with feline immunodeficiency virus.

OBJECTIVE: Cats naturally infected with feline immunodeficiency virus (FIV) are particularly susceptible to infection with opportunistic pathogens, suggesting that these animals are unable to develop an effective immune response against the pathogen. Previous studies have used CD4+:CD8+ lymphocyte ratios and mitogen blastogenesis to identify immunological abnormalities in FIV-infected cats. However, these studies provide limited information for understanding the nature of the cellular dysfunction in FIV-infected cats, particularly defects in antigen-specific immune responses. DESIGN: To investigate whether cats infected with FIV are less able to mount an immune response to previously unencountered antigens, we compared the development of antigen-specific cellular immunity at the stage of T-cell priming in uninfected and FIV-infected cats. INTERVENTIONS: The general immune status of cats was assessed by peripheral blood CD4+:CD8+ lymphocyte ratios (flow cytometry), and by lymphocyte blastogenesis response to T- and B-cell mitogens. In addition, we describe the development of an autologous culture system to measure specific priming of naive feline T-cells to soluble antigen in vitro. This assay was used to compare T-cell priming in uninfected cats and cats which had been infected with FIV for 6-27 months. RESULTS: As in HIV infection, CD4+:CD8+ lymphocyte ratios in FIV-infected cats were found to be inverted, due to a reduction in the percentage of CD4+ cells. In addition, lymphocyte blastogenesis to both T- and B-cell mitogens was significantly impaired in FIV-infected cats. Priming to keyhole limpet haemocyanin (KLH) elicited a late proliferative response resulting from the expansion of CD4+ (T-helper cells). T-cell growth factor secretion correlated with cell proliferation. Restimulation of cells with fresh antigen-presenting cells and antigen showed that antigen-specific T-cell priming had occurred in the initial culture. When primary proliferation responses in FIV-infected cats were examined, it was observed that naive CD4+ T-cells from FIV-infected cats were significantly impaired (P less than 0.001) in their ability to be primed to KLH when compared with uninfected controls. CONCLUSIONS: Impaired priming of naive CD4+ T-helper cells to antigen in FIV-infected cats may explain the increased susceptibility of these animals to infection by opportunistic pathogens. The poor ability of human patients with AIDS to develop humoral immunity following vaccination may also be caused by such a defect in T-cell priming.

Mucosal infection and vaccination against feline immunodeficiency virus.

Feline immunodeficiency virus (FIV) infection is a naturally occurring lentiviral infection of cats which progresses to immunodeficiency in a manner strikingly similar to that observed in HIV infection in man. The rectal and cervico-vaginal mucosae are common routes of transmission of HIV and it has been shown that the gastrointestinal tract is an important site of HIV infection and primary pathology. Although biting is the principle mode of transmission for FIV, we have shown that it is possible to reliably infect cats via both the rectal and vaginal routes. Using a biotin-streptavidin linked immunoperoxidase technique we have detected FIV core and envelope proteins in the colonic follicle associated epithelial cells, cells within the lymphoid follice and occasional cells in the lamina propria. Further, in the intestine we have detected FIV RNA and proviral DNA in epithelial cells, colonic lymphoid aggregates and isolated lamina propria cells. We have studied a group of asymptotic cats which have been rectally infected with FIV for 1 year or longer and shown an increase in the number of lamina propria CD8+ cells and greater levels of IL-2, IL-6, IL-10 and gamma-IFN mRNA. Since these cats remained clinically healthy these results might suggest that both local antibody and class I restricted cytotoxic lymphocytes (CTLs) may play a role in control of viral replication. We have investigated a range of vaccination regimes for their ability to generate responses which would protect from rectal challenge with virulent virus. Cats have been immunized with whole virus (FIV-pet, FIV-GLA-8), V3, V3MAP or C2 with cholera toxin (CT), or Quil A based adjuvants via rectal, intra-nasal, parenteral or targeted lymph node routes, and challenged rectally with ten mucosal cat infectious doses (MCID) of FIV-GLA-8. We have shown that the adjuvant effects of cholera toxin and Quil A are not influenced by the route of delivery (intraperitoneal (i.p.) versus rectal) with CT more effective in stimulating humoral and Quil A more effective in stimulating cellular responses to FIV antigens. However we have shown that, quantitatively, CT is more effective when used as an adjuvant via the intra-nasal than the rectal route. Recently, we have begun to investigate if the promising results obtained with targeted lymph node (TLN) vaccination in monkeys could be reproduced in the cat. We have shown that TLN was more effective than rectal immunisation in stimulating both humoral and proliferative responses. In a preliminary study we have also been able to detect FIV specific CTLs and have observed protection from rectal challenge in four out of four cats.

Reovirus type 2 in domestic cats: isolation and experimental transmission.

Five reovirus isolates were recovered in MA104 cell cultures from the faeces of three cats with nictitating membrane protrusion and diarrhoea, one cat with diarrhoea only and from one healthy cat. Four of these isolates were characterised as reovirus type 2 and one as reovirus type 3 by haemagglutination-inhibition and serum neutralization tests. Reovirus type 2 has not been reported previously in cats. Mild clinical signs of diarrhoea were noted in kittens infected experimentally with one of the feline reovirus type 2 isolates.

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.

Vaginal and rectal infection of cats with feline immunodeficiency virus.

The objective of this study was to examine the potential of vaginal and rectal mucosal routes for feline immunodeficiency virus (FIV) uptake and infection, as a model of mucosal HIV infection, and to determine the fate of virus at these mucosal sites following transmission of infection. SPF cats were exposed to FIV isolates (PET, GL-8, T637), administered as either cell-associated or cell-free inocula, via the rectum or vagina. Establishment of infection was confirmed by isolation of infectious FIV from peripheral blood mononuclear cells (PBMC), and by presence of FIV proviral DNA in PBMC using a nested polymerase chain reaction. Fate of virus in tissue taken at necropsy from cats infected for 6-48 weeks was assessed by localizing FIV core and envelope proteins, p24 and gp41, using a biotin-streptavidin linked immunoperoxidase (IP) technique. Cells susceptible to infection were identified by an in situ hybridization technique for FIV viral DNA and RNA. Cell-free, as well as cell-associated, virus was infectious across intact vaginal and rectal mucosal surfaces. Transmission was most successful using cell-associated inocula, and via the rectal route. Cells infected with FIV were detected by IP staining in the colon of 6/9 rectally challenged cats and 1/5 vaginally challenged cats. Virus was predominantly localized within the epithelium at the base of the colonic crypts associated with lymphoid aggregates (follicle associated epithelium; FAE), and within the lymphoid follicle itself. Occasional infected cells were also noted within the lamina propria. The distribution of FIV DNA positive cells in the colon was similar to that for FIV antigen whilst FIV RNA positive cells were found more extensively, including within the lamina propria and lymphoid follicle. FIV infected cells were not detected within the vagina, or colonic and ileac lymph nodes. Similar patterns of infected cells were seen in all of the positive cats, indicating that colonic tissues remain persistently actively infected with FIV. We conclude that the FIV/cat model of rectal and vaginal mucosal infection should prove useful for characterizing the mechanism by which HIV infects mucosal surfaces and as a challenge system for the design of vaccines effective at preventing HIV infection via rectal and vaginal routes.

Polymerase chain reaction and partial sequencing of a British isolate (T637) of feline immunodeficiency virus.

We have used the polymerase chain reaction (PCR) and direct sequencing of the amplified products to obtain information of the molecular nature of an FIV isolate, T637. Cats experimentally infected with T637 have progressed to clinical immunodeficiency disease. The 5' long terminal repeat (LTR), most of the genes coding for internal proteins (GAG) and surface proteins (ENV), and part of the polymerase (POL) gene have been sequenced. The LTR of T637 has 92% nucleic acid identity with the prototype strain, FIV-Petaluma and the Glasgow isolate, FIV-14, 89% with a Swiss isolate, FIVZ2, and 95% with the PPR isolate. Both GAG and POL genes of T637 share extensive homology with Petaluma and PPR. In the ENV gene, T637 has 91% nucleic acid homology with Petaluma and 86% with PPR, and an overall amino acid homology of between 81-87%. For the surface (SU) region of the ENV gene product, T637 has 89% amino acid homology with Petaluma and FIVZ2 and 86% with PPR.

16S rDNA comparison demonstrates near identity between an United Kingdom Haemobartonella felis strain and the American California strain.

A handful of North American (USA) strains of the uncultured erythrocytotrophic pathogen of cats, Haemobartonella felis, have been differentiated by comparison of the 16S rRNA gene sequences. Using this approach, an UK strain was characterised, providing an identity for a non-USA H. felis for the first time. This strain shared close phylogenetic homology with the USA Californian strain.

Determination of salivary and serum immunoglobulin concentrations in the cat.

The concentrations of immunoglobulin(Ig)G, IgM, and IgA were determined in unstimulated saliva (n=14), stimulated saliva (n=6), and serum (n=14) from healthy adult cats. Analysis by single radial immunodiffusion (SRID) was compared with class-specific enzyme linked immunoassays (ELISA), and good correlation was demonstrated between the two techniques. Mean (s.d.) serum concentrations of 19.08 (5.38) mg/ml IgG, 2.04 (0.83) mg/ml IgM and 2.6 (2.16) mg/ml IgA were obtained by SRID. The immunoglobulin concentrations of the saliva samples frequently fell below the quantification limits for SRID, however, all samples could be quantified by ELISA making this the method of choice for the determination of salivary immunoglobulin concentrations. IgA was the predominant class of immunoglobulin secreted by the major feline salivary glands, and the concentration of each immunoglobulin class was greater in unstimulated versus stimulated saliva. Analysis of sequential unstimulated saliva samples collected each morning and evening over a 4-day period from four cats revealed the salivary immunoglobulin concentrations to be relatively constant.

Autoimmune haemolysis in the dog: relationship between anaemia and the levels of red blood cell bound immunoglobulins and complement measured by an enzyme-linked antiglobulin test.

A direct enzyme-linked antiglobulin test (DELAT) was used to measure the levels of red blood cell (RBC) bound IgG, IgM, IgA and C3 in dogs with autoimmune haemolytic anaemia (AIHA). At presentation, one or more DELAT parameters was raised in each AIHA case, and the RBC were typically coated with immunoglobulin of more than one class, together with C3. There was no relationship between the levels of RBC-bound IgG, IgM or IgA and the severity of the anaemia, although a significant negative correlation (rs = -0.66, P < 0.02) was found between bound C3 and blood haemoglobin concentration. These results indicate that the level of sensitisation of erythrocytes with IgG alone is not a reliable predictor of the severity of haemolysis in different cases, and that the pathogenesis of AIHA can be complex, involving multiple immunoglobulin classes and complement in the destruction of RBC. A significant relationship (rs = 0.63, P < 0.02) was found between serum IgG concentration and haemoglobin levels, and it is suggested that this may be due to free IgG inhibiting the interaction of IgG-sensitised RBC with macrophages. Serial measurements from individual AIHA cases during treatment revealed that the levels of RBC-bound immunoglobulins fell simultaneously with improvements in anaemia. In one dog, a relapse was associated with increases in bound IgG and IgM. Transient relative reticulocytopenia at presentation was common, but was not related to the severity of the anaemia. However, in other cases there was a persistent failure to increase RBC production, which was associated with slower recovery.