Flow cytometric detection of alpha-1-acid glycoprotein on feline circulating leucocytes

To assess whether alpha‐1‐acid glycoprotein (AGP) can be detected on the membrane of feline circulating leucocytes. Design The presence of AGP on circulating leucocytes was investigated in both clinically healthy cats and cats with different diseases. A group of feline coronavirus (FCoV)‐positive cats, comprising cats with feline infectious peritonitis (FIP) and cats not affected by FIP but seropositive for FCoV, were included in this study because the serum concentration of AGP increases during FCoV infection. Procedure Flow cytometry (using an anti‐feline AGP antibody), serum protein electrophoresis, routine haematology and measurement of the serum AGP concentration were performed using blood samples from 32 healthy cats (19 FCoV‐seropositive), 13 cats with FIP and 12 with other diseases (6 FCoV‐seropositive). The proportion of cats with AGP‐positive leucocytes in the different groups (e.g. controls vs sick; FIP vs other diseases, etc.) or in cats with different intensities of inflammatory response was compared using a Chi‐square test. Results AGP‐positive leucocytes were found in 23% of cats. Compared with controls, the proportion of patients with positive granulocytes and monocytes was higher among sick cats (especially cats with diseases other than FIP) and cats with high serum AGP concentration, but not in cats with leucocytosis or that were FCoV‐seropositive. Conclusion AGP‐positive leucocytes can be found in feline blood, especially during inflammation. Conversely, no association between AGP‐positive leucocytes and FIP was found. Further studies are needed to elucidate the mechanism responsible for this finding and its diagnostic role in cats with inflammation.     

Sensitivity of Tru-cut and fine needle aspiration biopsies of liver and kidney for diagnosis of feline infectious peritonitis

BACKGROUND: The detection of typical lesions and feline coronavirus (FCoV) antigen in tissues is the only conclusive method for making a diagnosis of feline infectious peritonitis (FIP). A positive result using Tru-cut biopsy (TCB) and fine-needle aspiration biopsy (FNAB) has high diagnostic specificity, but information about the capacity of these techniques to correctly identify cats with FIP lesions is not available. OBJECTIVES: The diagnostic sensitivity of TCB and FNAB for detecting liver and kidney histologic lesions caused by FIP was evaluated. METHODS: TCB and FNAB specimens collected mainly at necropsy from 25 cats with FIP were analyzed. Diagnostic sensitivity was calculated on the basis of the number of false-negative and true-positive specimens, compared with the number of organs bearing histologic lesions of FIP. RESULTS: Diagnostic sensitivity was higher for hepatic TCB (64%) and FNAB (82%) than for renal (39% and 42%, respectively) procedures. A high percentage of renal cytologic and TCB specimens were inadequate. Combined analysis of TCB and FNAB specimens collected from the same organ increased the diagnostic sensitivity for liver (86%) and kidney (48%). The sensitivity of immunohistochemical/cytochemical analysis was low (11-38% depending on the technique), probably due to variable distribution of feline coronavirus in the lesions. CONCLUSION: Biopsy of liver and kidney can correctly identify FIP lesions. However, false-negative results or inadequate samples occur with moderate frequency, especially for immunochemical analysis. Diagnostic sensitivity may be increased when both TCB and FNAB specimens from the same organ are examined.     

Quarantine protects Falkland Islands (Malvinas) cats from feline coronavirus infection

Feline coronavirus (FCoV) causes feline infectious peritonitis (FIP). Since 2002, when 20 cats on the Falkland Islands were found to be FCoV seronegative, only seronegative cats could be imported. Between 2005-2007, 95 pet and 10 feral cats tested negative by indirect immunofluorescence antibody (IFA) analysis using two strains of type II FCoV, two transmissible gastroenteritis virus assays, an enzyme-linked immunosorbent assay and rapid immunomigration test. Twenty-four samples (23%) showed non-specific fluorescence, mostly attributable to anti-nuclear antibodies (ANA). The reason for ANA was unclear: reactive samples were negative for Erhlichia canis antibodies; seven were feline immunodeficiency virus positive, but 15 were negative. It was not possible to determine retrospectively whether the cats had autoimmune disease, hyperthyroidism treatment, or recent vaccination which may also cause ANA. The FCoV/ FIP-free status of the Falkland Islands cats should be maintained by FCoV testing incoming cats. However, ANA can complicate interpretation of IFA tests.     

An enzyme-linked immunosorbent assay using canine coronavirus-infected CRFK cells as antigen for detection of anti-coronavirus antibody in cat

From the reasons that canine coronavirus (CCV) grows more efficiently than feline coronavirus in a cell culture and they are mutually related in their antigenicities, an enzyme-linked immunosorbent assay (ELISA) using CCV-infected feline kidney (CRFK) cells as substrate antigens was developed for detection of anti-coronavirus antibodies in cats. It was indispensable for generating coronavirus-specific ELISA antibody activities that the sample was applied to the mock-infected, normal CRFK cells in parallel with the CCV-infected cells and then the optical density values given by the mock-infected cell antigen were subtracted from those given by the virus-infected cell antigen. On the basis of ELISA antibody titers obtained in sera from the cats experimentally infected with CCV and from the spontaneous feline infectious peritonitis (FIP) cases, the ELISA described in the present study was found to be applicable as a simple and easy serologic test which was able to detect anti-coronavirus antibodies as efficiently as the indirect immunofluorescence assay with homologous FIP virus.     

Using direct immunofluorescence to detect coronaviruses in peritoneal in peritoneal and pleural effusions

Twenty-one cases of feline infectious peritonitis (FIP) were diagnosed using a direct immunofluorescence test on cytocentrifuged pleural and peritoneal effusions from cats sampled in vivo (11 cases) and at necropsy (10 cases). A commercial fluorescent polyclonal antiserum of feline origin reacting with FIPV and cross reacting with transmissible gastroenteritis virus and canine coronavirus was used. Eleven cats with ascites of a different origin were used as negative controls. The direct immunofluorescence test was 97 per cent reliable (31 cases of 32) and can be used in routine diagnosis.     

A micro-enzyme-linked immunosorbent assay (ELISA) test for detection of feline leukemia virus in cats

The performance of a micro ELISA test for detection of feline leukemia virus (FeLV) infection was evaluated. The test was found specific for FeLV and feline sarcoma virus (FeSV) group-specific antigens in blood, plasma or serum of infected cats. Other common feline pathogens were negative to the test.Quantities as little as 7.8 ng of p-27 (the major group specific antigen of FeLV) per ml of sample gave positive results. The correlation between the micro ELISA test and the indirect immunofluorescent test commonly used for diagnosis of FeLV infection was 98% in 116 clinical cases and 184 samples from cats inoculated with FeLV and 100% in 100 specific pathogen-free cats.     

Feline infectious peritonitis: a worldwide serosurvey.

Feline sera from 13 countries were assayed for coronavirus antibody, using a heterologous indirect immunofluorescence test. Significantly higher percentages of antibody carriers were obtained during testing randomly collected sera from mature males (greater than 1 year old) than in testing females of the same age. Antibodies were infrequently found in immature cats (less than 6 months old); at 1 year of age or older, a plateau was reached and little change in the percentage of seroconverted animals was observed. Differences were not detected between purebred cats vs mixed-breed cats or household vs stray cats. In animals showing clinical signs of feline infection peritonitis (FIP), antibodies were encountered with higher frequency than in clinically healthy cats. Significant differences in antibody incidence were found between countries, with a range between less than 10% and greater than 50% of seropositive individuals. Antibodies were detected in sera from an isolated cat population (Marion Island) and from wild-caught cheetahs (Acinonyx jubatus). The antibody specificity for FIP virus was confirmed by neutralization tests. The antibody pattern in randomly collected solitary cats, in catteries, and cats with clinical FIP showed characteristic differences in titer and incidence. The implications of these results for the epizootiology of FIP are discussed.     

Shifts in circulating lymphocyte subsets in cats with feline infectious peritonitis (FIP): pathogenic role and diagnostic relevance

Cats with feline infectious peritonitis (FIP) are usually lymphopenic and have lymphoid depletion evident in spleen and lymph nodes. In particular, the number of CD4+ lymphocytes in tissues decreases during the evolution of FIP lesions. This decrease is most likely due to increased lymphocyte apoptotic rate. In contrast, cats infected with the Feline Coronavirus (FCoV) develop a follicular hyperplasia in the peripheral lymph nodes. The current study was devised to evaluate the possible pathogenic role of shifts in circulating lymphocyte subsets in FIP. Peripheral blood from cats with FIP was evaluated and compared with peripheral blood from clinically healthy cats living in both FCoV-free and FCoV-endemic catteries. Blood from cats with diseases other than FIP was also examined in order to define the diagnostic relevance of the changes. Lymphocyte subsets were analysed by flow cytometry, using a whole blood indirect immunofluorescence technique and mAbs specific for feline CD5, CD4, CD8, CD21. The results of the current study suggest that cats recently infected with FCoV that do not develop the disease have a transient increase in T cells; cats from groups with high prevalence of FIP have a moderate but persistent decrease in T cell subsets; cats with FIP have a very severe decrease in all the subsets of lymphocytes. Moreover, during FIP many lymphocytes do not express any membrane antigen, most likely due to early apoptosis. Cats with diseases other than FIP also had decreased number of lymphocytes: as a consequence, the diagnostic relevance of these findings is very low. Nevertheless, the lack of flow cytometric changes had a high negative predictive value (NPV), thus allowing to exclude FIP from the list of possible diagnoses in cats with normal cytograms.     

An immunoturbidimetric assay for rapid quantitative measurement of feline alpha-1-acid glycoprotein in serum and peritoneal fluid

BACKGROUND: Alpha-1-acid glycoprotein (AGP) is an acute phase protein that increases in concentration in infectious and inflammatory conditions. The serum and peritoneal fluid concentrations of AGP may be useful in the diagnosis of feline infectious peritonitis (FIP), a lethal disease of cats. Currently AGP can be measured by radioimmunodiffusion (RID) assays, which are time consuming and difficult. OBJECTIVES: The objectives of this study were to develop a rapid immunoturbidimetric assay for measurement of AGP in feline serum and peritoneal fluid and to compare the results with those obtained by RID. METHODS: AGP was purified by perchloric acid precipitation and ion-exchange chromatography from a pool of peritoneal fluid obtained from cats with FIP, as determined by a panel of laboratory tests, including serum AGP concentration, albumin: globulin ratio, and total protein concentration, anti-coronavirus antibody titers, and effusion analysis. The purified AGP in a complete Freund's adjuvant and Tween 20 mixture was injected into a sheep and blood was collected at monthly intervals. Anti-AGP antiserum, as confirmed by ELISA and Western blot techniques, and a pool of peritoneal fluid from cats with FIP were used to prepare standards. Clinical samples of feline peritoneal fluid (n=55) and serum (n=59) were assayed for AGP and results from the immunoturbidimetric and RID methods were compared. RESULTS: Significant correlation (P < .001) was obtained between methods for both peritoneal fluid (R2=.9259) and serum (R2=.9448) samples. Coefficients of variation for the immunoturbidimetric method were <5%. CONCLUSIONS: This rapid immunoturbidimetric assay for measurement of feline AGP in serum and peritoneal fluid may be of value in the diagnosis of FIP and possibly other inflammatory diseases in cats.     

Morbidity,Mortality and Coronavirus Antigen in Previously Coronavirus Free Kittens Placed in Two Catteries with Feline Infectious Peritonitis

Serologically coronavirus free kittens were placed in 2 catteries with a history of feline infectious peritonitis (FIP), each cattery representing 1 of the 2 different predominant clinical characteristics of FIP - effusive and granulomatous. The kittens were clinically observed for 100 days. A 100% morbidity and a 90% mortality was observed. The first signs were observed after 14 and 27 days respectively. The clinical pattern of the disease was similar in all kittens and showed a pattern of recurrent periods of conjunctivitis, upper respiratory and gastrointestinal signs. Once developed, wasting and signs of CNS disturbances were consistent. The “effusive strain” had a 2 weeks earlier onset of signs and death, and a 40% outcome of effusive FIP. Mean survival times during the observation period were 57 ±26 and 57 ±16 (mean ±SD in days), respectively. The death rates were similar in both groups. Feline coronavirus (FCoV) antigen was immunohistochemically detected using indirect immunofluorescence and was present in all kittens and in 93% of the 5 investigated organs (lung, liver, spleen, kidney, and mesenteric lymph node).     

猫细小病毒的遗传演化及分离毒株的致病性分析

本研究旨在了解猫细小病毒（feline parvovirus,FPV）流行株的遗传演化情况及分离毒株的致病性。2018—2020年,在山东地区采集54份疑似猫瘟粪便拭子,并通过PCR和VP2基因克隆进行VP2基因全长测序,构建遗传进化树,并推导出氨基酸序列并与疫苗株进行比对,分析遗传变异情况。用F81细胞分离培养1株FPV毒株,命名为FPV-QDC20,经电镜观察、间接免疫荧光、血凝试验、TCID₅₀测定、全基因测序及动物回归试验研究该毒株生物学特性。结果表明,采集样品中16份样品VP2基因全长测序成功,其中,15份为FPV,1份为猫源犬细小病毒（CPV）。构建系统进化树显示,本研究的FPV毒株均处于同一大分支,与中国其他地区已发表的FPV毒株亲缘关系较近,与欧洲分离株以及疫苗株亲缘关系较远。氨基酸序列分析表明,某些关键位点的改变可能导致宿主范围和感染性的改变,有可能导致免疫失败情况发生。毒株QDBL2毒株中出现了80、93、103三个FPV保守位点的变异,或许与犬猫细小病毒的共感染和重组有关。动物回归试验表明,毒株FPV-QDC20有较强致病性,试验猫出现典型的临床症状和病理变化,并最终死亡。本研究有助了解我国FPV毒株遗传演化方向,为将来的疫病监控和疫苗研究提供参考。     

Use of anti-coronavirus antibody testing of cerebrospinal fluid for diagnosis of feline infectious peritonitis involving the central nervous system in cats

OBJECTIVE: To assess the use of measuring anti-coronavirus IgG in CSF for the diagnosis of feline infectious peritonitis (FIP) involving the CNS in cats. DESIGN: Prospective study. SAMPLE POPULATION: CSF and serum samples from 67 cats. PROCEDURES: CSF and serum samples were allocated into 4 groups: cats with FIP involving the CNS (n = 10), cats with FIP not involving the CNS (13), cats with CNS disorders caused by diseases other than FIP (29), and cats with diseases other than FIP and not involving the CNS (15). Cerebrospinal fluid was evaluated for concentrations of erythrocytes, leukocytes, and total protein. Anti-coronavirus IgG was measured in CSF and serum by indirect immunofluorescence assay. RESULTS: CSF IgG (range of titers, 1:32 to 1:4,096) was detected in 12 cats, including 6 cats with neurologic manifestation of FIP, 4 cats with FIP not involving the CNS, and 2 cats with brain tumors. Cerebrospinal fluid IgG was detected only in cats with correspondingly high serum IgG titers (range, 1:4,096 to 1:16,384) and was positively correlated with serum IgG titers (r = 0.652; P < 0.01), but not with any other CSF parameter. Blood contamination of CSF resulted in < or = 333 erythrocytes/microL in cats with CSF IgG. CONCLUSIONS AND CLINICAL RELEVANCE: The correlation between serum and CSF IgG and the fact that CSF IgG was detected only in strongly seropositive cats suggested that CSF anti-coronavirus IgG was derived from blood. Measurement of anti-coronavirus IgG in CSF was of equivocal clinical use.     

Use of albumin quotient and IgG index to differentiate blood- vs brain-derived proteins in the cerebrospinal fluid of cats with feline infectious peritonitis

BACKGROUND: Inflammation of the central nervous system (CNS) is a frequent condition in cats but etiology often remains unsolved. Routine cerebrospinal fluid (CSF) analysis can be extended through the calculation of the albumin quotient (Q(alb)), a marker of the integrity of the blood-brain barrier (BBB), and IgG index, an estimate of intrathecal IgG synthesis. OBJECTIVES: The purpose of this study was to validate nephelometric methods for CSF protein analysis, and to use the Q(alb) and IgG index to discriminate blood- and brain-derived immunoglobulin fractions in cats with feline infectious peritonitis (FIP). METHODS: Cats presented to our clinic between 2001 and 2005 were included in the study based on clinical and laboratory data and histopathologic findings at necropsy. Cats were grouped as having nonneurologic disease (controls; n=37), brain tumors (n=8), FIP involving the CNS (n=12), and extraneural FIP (n=12). CSF-total protein (TP) was measured and albumin and IgG concentrations were measured in paired CSF/serum samples; Q(alb) and IgG index were calculated. Intraassay and interassay precision of the nephelometric assays were determined using pooled samples. RESULTS: Coefficients of variation for the nephelometric assays ranged from 2.7% to 7.2%. In control cats, CSF-TP concentration ranged from 0.06 to 0.36 g/L, Q(alb) ranged from 0.6 to 5.7 x 10(-3), and IgG index ranged from 0.3 to 0.6. Q(alb) and IgG index were significantly higher in cats with brain tumors and cats with CNS-FIP compared with other groups. Compared with control cats, pleocytosis was evident in 8 of 12 (67%) cats and CSF-TP was increased in 3 of 12 (25%) cats with CNS-FIP. CONCLUSION: Nephelometry is a reliable method for measurement of CSF protein, albumin, and IgG in cats. The Q(alb) and IgG index did not identify a CSF protein pattern specific for BBB dysfunction or intrathecal IgG synthesis in cats with CNS-FIP.     

Evaluation of antibodies against feline coronavirus 7b protein for diagnosis of feline infectious peritonitis in cats

OBJECTIVE: To determine whether expression of feline coronavirus (FCoV) 7b protein, as indicated by the presence of specific serum antibodies, consistently correlated with occurrence of feline infectious peritonitis (FIP) in cats. SAMPLE POPULATION: 95 serum samples submitted for various diagnostic assays and 20 samples from specific-pathogen-free cats tested as negative control samples. PROCEDURES: The 7b gene from a virulent strain of FCoV was cloned into a protein expression vector. The resultant recombinant protein was produced and used in antibody detection assays via western blot analysis of serum samples. Results were compared with those of an immunofluorescence assay (IFA) for FCoV-specific antibody and correlated with health status. RESULTS: Healthy IFA-seronegative cats were seronegative for antibodies against the 7b protein. Some healthy cats with detectable FCoV-specific antibodies as determined via IFA were seronegative for antibodies against the 7b protein. Serum from cats with FIP had antibodies against the 7b protein, including cats with negative results via conventional IFA. However, some healthy cats, as well as cats with conditions other than FIP that were seropositive to FCoV via IFA, were also seropositive for the 7b protein. CONCLUSIONS AND CLINICAL RELEVANCE: Expression of the 7b protein, as indicated by detection of antibodies against the protein, was found in most FCoV-infected cats. Seropositivity for this protein was not specific for the FCoV virulent biotype or a diagnosis of FIP.     

Seroprevalence of Toxoplasma gondii and Neospora caninum infection of cats in Hungary

Blood samples were collected from 330 cats in Hungary in order to evaluate their seroconversion to Toxoplasma gondii and Neospora caninum using the indirect fluorescent antibody test (IFAT). The overall prevalence of toxoplasmosis was 47.6%, the prevalence being 22.4% among urban, 50% among suburban and 61.3% among rural animals. Significantly more cats had high IFAT titres (1:640 to 1:5120) in the countryside. Female cats were more frequently infected with T. gondii than males (53.3% vs. 39.3%), and seropositivity increased with the age of animals. The prevalence (0.6%) and titre (1:40) of antibodies to N. caninum was low. Sixty-two cats were also screened for seroconversion to feline infectious peritonitis (FIP) virus. Higher titres to T. gondii were more frequently detected among FIP-positive cats, but this difference was non-significant due to the small number of cats with concurrent infection.     

GS-441524对自然感染的猫传染性腹膜炎的治疗效果观察

试验旨在观察GS-441524对自然感染的猫传染性腹膜炎（FIP）病例的临床疗效，为临床用药提供参考。试验招募了25只于中国农业大学动物医院确诊为FIP的患猫，随机分为高剂量组（5 mg/（kg·d））（12只）和低剂量组（2.5 mg/（kg·d））（13只），每日皮下注射GS-441524治疗并记录体重、体温、注射药物的疼痛反应及每周的实验室及影像学检查结果以评价药物疗效。设定治疗周期为4周，部分病例根据实际情况延长治疗时间。结果显示，共计20只湿性FIP和3只干性FIP患猫完成试验，2只患猫退出。治疗时间为4~18周。20只湿性FIP患猫中，2只在1周内死亡，1只体腔积液增加，17只用药1周后积液减少，用药2~3周后积液消失。3只干性FIP患猫中，2只患猫的肠系膜淋巴结在用药1~2周后减小，1只无明显变化。所有患猫的精神和食欲在用药3~5 d内改善；体重在1~2周内开始增长；5只发烧的患猫用药2~3 d后体温恢复正常；14只贫血的患猫用药1~10周后恢复正常；16只患猫出现白细胞数量升高且淋巴细胞数量下降或中性粒细胞数量升高，用药1~2周内开始好转。所有患猫血清中白蛋白和球蛋白的比值（白球比）均<0.8，其中9只总蛋白升高，4只白蛋白降低，14只球蛋白升高，用药1~2周后开始好转。高剂量组的患猫4周药物有效率和治愈率分别为81.8%和60.0%，低剂量组的患猫4周药物有效率和治愈率分别为75.0%和22.2%。用药4周前后，高剂量组的患猫除白细胞总数（WBC）和白蛋白（ALB）外，其余指标均差异显著或极显著（P<0.05；P<0.01）；而低剂量组的患猫仅体重差异显著。除血红蛋白（HGB）、WBC和ALB外，药物对患猫的体重、红细胞（RBC）、红细胞压积（HCT）、淋巴细胞（LYM）、中性粒细胞（NEU）、总蛋白（TP）、球蛋白（GLOB）及白球比（A/G）改善情况差异显著（P<0.05），且高剂量药物效果更佳。综上，GS-441524能有效治疗自然感染的FIP，高剂量（5 mg/（kg·d））疗效更佳，最短治疗周期为4周。     

Therapeutic effects of recombinant feline interferon-omega on feline leukemia virus (FeLV)-infected and FeLV/feline immunodeficiency virus (FIV)-coinfected symptomatic cats

The clinical efficacy of a recombinant feline interferon, rFeIFN-omega, was evaluated for the treatment of cats presented with clinical signs associated with feline leukemia virus (FeLV) infection and FeLV/feline immunodeficiency virus (FIV) coinfection in the field. In this multicentric, double-blind, placebo-controlled trial, 81 cats meeting the inclusion criteria were randomly placed into 2 groups and treated subcutaneously with rFelFN-omega (1 million [M]U/kg per day) or placebo once daily for 5 consecutive days in 3 series (day 0, 14, 60). The cats were monitored for up to 1 year for clinical signs and mortality. During the initial 4-month period, interferon (IFN)-treated cats (n = 39) had significantly reduced clinical scores compared with placebo (n = 42), with all cats having received concomitant supportive therapies. Compared with the control, the IFN-treated group showed significantly lower rates of mortality: 39% versus 59% (1.7-fold higher risk of death for controls) at the 9-month time point and 47% versus 59% (1.4-fold higher risk of death for controls) at the 12-month time point. The IFN treatment was associated with minor but consistent improvement in abnormal hematologic parameters (red blood cell count, packed cell volume, and white blood cell count), apparently underlying the positive effects of IFN on clinical parameters. These data demonstrate that rFeIFN-omega initially has statistically significant therapeutic effects on clinical signs and later on survival of cats with clinical signs associated with FeLV infection and FeLV/FIV coinfection.     

Prevalences of feline leukaemia virus and feline immunodeficiency virus infections in cats in Sydney

Objective To determine prevalences of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) infections in ‘healthy’ cats that, through acute misadventure or other circumstance, were presented to veterinary practitioners. Prevalences of FeLV and FIV in this population were compared to those in a population of predominantly sick cats. Design and procedures Serum specimens were obtained over a 2-year period from 200 cats oldeer than 1 year of age presented to veterinary clinics for routine procedures, including cat fight injuries or abscesses, vehicular trauma, neutering, dental scaling, vaccination, grooming or boarding. An additional 894 sera were obtained over approximately the same period from specimens submitted by veterinarians to a private clinical pathology laboratory, mainly from sick cats suspected of having immune dysfunction, but including some sera from healthy cats being screened prior to FeLV vaccination. FIV antibody and FeLV antigen were detected in samples using commercial enzyme immunoassays. Results Amongst 200 ‘healthy’ cats, the prevalence of FeLV infection was 0 to 2%, and the prevalence of FIV was 6.5 to 7.5%, depending on the stringency of the criteria used to define positivity. FIV infection was significantly more prevalent in cats which resided in an inner city environment (P = 0.013). Of the 894 serum specimens submitted to the laboratory by practitioners, 11/761 (1.4%) were FeLV positive, while 148/711 (20.8%) were FIV positive. The prevalence of FIV was significantly higher in these predominantly ‘sick’ cats than in cats seen for routine veterinary procedures (P < 0.00001), while there was no difference in the prevalence of FeLV (P = 0.75) Conclusions The prevalence of FeLV and FIV in healthy cats may have been substantially overestimated in some previous Australian surveys. FeLV infection would appear to be a rare cause of disease in Australian cats. The higher prevalence of FIV positivity in sick as opposed to healthy cats infers that FIV infection contributes to the development of disease.