Effect of feline interferon-omega on the survival time and quality of life of cats with feline infectious peritonitis

BACKGROUND: There is no therapy with proven efficacy to treat cats with feline infectious peritonitis (FIP). HYPOTHESIS: Feline interferon-omega (FeIFN-omega) prolongs survival time and increases quality of life in cats with FIP. ANIMALS: Thirty-seven privately owned cats were subjects of this study. METHODS: The study was performed as a placebo-controlled double-blind trial. Feline infectious peritonitis was confirmed by histology or immunostaining of feline coronavirus (FCoV) antigen in effusion or tissue macrophages or both. The cats were randomly selected for treatment with either FeIFN-omega or a placebo. All cats received adjunctive treatment with glucocorticoids and antibiotics and passive immunization with Feliserin. RESULTS: There was no statistically significant difference in the survival time of cats treated with FeIFN-omega versus placebo or in any other variable evaluated (with the exception of the lymphocyte count). The cats survived between 3 and 200 days (median, 9 days). There was only 1 long-term survivor (> 3 months), and the cat was in the FeIFN-omega group. CONCLUSION AND CLINICAL RELEVANCE: No effect of FeIFN-omega on survival time or quality of life could be demonstrated in this study.     

Prevalence of diseases of the spinal cord of cats

A retrospective review of records of 205 cats with histologically confirmed disease of the spinal cord was performed to identify the prevalence of disease in this nonrandomly selected population of cats. Clinical records were reviewed, and age, duration of neurologic illness, and clinical and histopathologic findings in cats with spinal cord disease were abstracted. Disease processes were classified into 7 categories and 23 groups. The most common diseases affecting the spinal cord of cats were feline infectious peritonitis (FIP), lymphosarcoma (LSA), and neoplasia of the vertebral column secondarily affecting the spinal cord. Information on age, onset and duration of clinical signs, and lesion localization at the postmortem examination in cats belonging to the 7 categories of disease were analyzed to create a practical list of differential diagnoses. Cats were also subcategorized into 3 groups based on their age at death. FIP was the most common disease of cats younger than 2 years of age. LSA and vertebral column neoplasia were the most common diseases affecting cats between 2 and 8 years of age. Vertebral column neoplasia was the most common disease affecting cats older than 8 years of age. Results of this histopathologic study showed that FIP and LSA were the most common disease processes affecting the spinal cord of cats. However, at least 21 other groups of diseases and their relative prevalence were identified.     

Characterisation of canine parvovirus strains isolated from cats with feline panleukopenia

Unlike the original canine parvovirus type 2 (CPV-2), CPV-2 variants have gained the ability to replicate in vivo in cats but there is limited information on the disease patterns induced by these variants in the feline host. During 2008, two distinct cases of parvoviral infection were diagnosed in our laboratories. A CPV-2a variant was identified in a 3-month-old Persian kitten displaying clinical sign of feline panleukopenia (FPL) (acute gastroenteritis and marked leukopenia) and oral ulcerations, that died eight days after the onset of the disease. Two pups living in the same pet shop as the cat were found to shed a CPV-2a strain genetically identical to the feline virus and were likely the source of infection. Also, non-fatal infection by a CPV-2c strain occurred in a 2.5-month-old European shorthair kitten displaying non-haemorrhagic diarrhoea and normal white blood cell counts. By sequence analysis of the major capsid protein (VP2) gene, the feline CPV-2c strain showed 100% identity to a recent canine type-2c isolate. Both kittens had been administered multivalent vaccines against common feline pathogens including FPL virus. Whether and to which extent the FPL vaccines can protect cats adequately from the antigenic variants of CPV-2 should be assessed.     

Interferon-gamma in the serum and effusions of cats with feline coronavirus infection

The aim of this study was to quantify and compare interferon-γ (IFN-γ) concentrations in the serum of clinically normal cats infected with feline coronavirus (FCoV) with its concentration in the sera and effusions of cats with feline infectious peritonitis (FIP), a disease associated with infection with a mutated form of FCoV.Clinically normal FCoV-infected cats living in catteries with a high prevalence of FIP had the highest serum IFN-γ concentrations. The serum concentration of IFN-γ was not significantly different in cats with FIP compared with clinically normal FCoV-infected animals living in catteries with a low prevalence of the disease. Moreover, the concentration of IFN-γ was significantly higher in the effusions than in the serum of cats with FIP, probably due to IFN-γ production within lesions. These findings support the hypothesis that there is a strong, ‘systemic’ cell mediated immune response in clinically normal, FCoV-infected cats and that a similar process, albeit at a tissue level, is involved in the pathogenesis of FIP.     

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.     

Epigenetic transmission of feline infectious peritonitis

Feline Infectious Peritonitis (F.I.P.) was diagnosed in the kittens of two successive litters born to a female presumed also infected.At the same time, the two fathers and the other subjects of the cattery remained asymptomatic of F.I.P.The clinical observations, supported by electrophoretic data, suggest the possibility of a direct transmission of the disease by the mother to her offspring, either by the transplacentary pathway (epigenetic transmission) or via the milk.     

Antibody-mediated enhancement of disease in feline infectious peritonitis: Comparisons with dengue hemorrhagic fever

Non-immune kittens passively immunized with feline serum containing high-titered antibodies reactive with feline infectious peritonitis virus (FIPV) developed a more rapid disease after FIPV challenge than did kittens pretreated with FIPV antibody-negative serum. Antibody-sensitized, FIPV challenged—kittens developed earlier clinical signs (including pyrexia, icterus, and thrombocytopenia) and died more rapidly than did non-sensitized, FIPV-challenged kittens. Mean survival time in sensitized kittens was significantly (P < 0.05) reduced compared to non-sensitized kittens (mean ± SEM, 10.0 ± 0.6 days vs. 28.8 ± 8.3 days, respectively). Lesions induced included fibrinous peritonitis, disseminated pyogranulomatous inflammation and necrotizing phlebitis and periphlebitis. FIPV antigen, immunoglobulin G, complement (C3) and fibrinogen were demonstrated in lesions by immunofluorescence microscopy.The pathogenesis of dengue hemorrhagic fever (DHF) in persons bears striking resemblance to that of FIP in experimental kittens. In both FIP and DHF, non-neutralizing antibody may promote acute disease by enhancement of virus infection in mononuclear phagocytes or by formation of immune complexes, activation of complement and secondary vascular disturbances.     

成都地区猫传性腹膜炎病毒ORF3、7b以及S基因七肽重复区1序列的分析

猫传性腹膜炎(FIP)是由猫冠状病毒引起的猫科常见致死性传染病。为分析成都地区猫传性腹膜炎病毒(FIPV)部分基因的序列特征,本研究从11只FIP患猫的腹水中提取总RNA,采用普通PCR或套式PCR对FIPV的非结构蛋白基因ORF3 (3a、3b和3c)、7b以及S基因七肽重复区1 (HR1)序列进行PCR扩增并测序。结果显示:检测到FIRV的上述几个基因均呈遗传多样性,序列存在很大的个体间差异。3a和3b基因主要表现为氨基酸突变,3c基因在约89%的样品中存在截短。7b基因有7个位点的氨基酸被完全替换。S基因HR1序列融合肽的1045位甲硫氨酸被亮氨酸替换,其下游的1057位丝氨酸被丙氨酸替换。遗传进化树显示,本实验扩增的FIRV 7b及S基因HR1序列与GenBank中国外FIPV相应基因序列亲缘性较高。推测3c基因的截短和/或某些氨基酸的替换的共同作用与病毒的致病性有关。本研究结果为FIP的临床确诊提供了分子诊断依据,增加了临床诊断结果的可靠性。     

A comparison between immunofluorescence staining on smears from Membrana nictitans (M3 test), immunohistopathology and routine pathology in cats with suspected feline infectious peritonitis (FIP).

An indirect immunofluorescence method using smears from membrana nictitans (M3 test) to diagnose feline corona virus (FCV) infection was compared with immunohistopathology (using indirect immunofluorescence assay (IFFA) performed on organs (IFO], and routine pathology (RP) in cats with suspected feline infectious peritonitis (FIP). A close correlation between the 2 immunofluorescence methods (IFO and M3) was observed. Although the M3 test requires samples from only 1 organ per animal, both the sensitivity and specificity were high (80%), when compared to IFO (using samples from an average of 5 organs per animal). In 21% of the cats with suspected FIP typical pathological lesions were found. As the M3 test is relatively easy to perform, it could reduce work-load of pathology laboratories and provide valuable data for clinical and epidemiological use.     

Prognostic factors in cats with feline panleukopenia

Background: Feline panleukopenia is a highly contagious and often lethal disease. Objective: The purpose of the study was to identify prognostic factors for survival of cats with panleukopenia. Animals: Between 1990 and 2007, 244 cats were diagnosed with panleukopenia in the Clinic of Small Animal Medicine, LMU University of Munich, Germany. Diagnosis was established by electron microscopy, polymerase chain reaction of feces or blood, antigen ELISA of feces, pathognomonic histopathological lesions at necropsy, or some combination of these procedures. Methods: Medical records of each cat were evaluated retrospectively. Results: Survival rate was 51.1%. No significant correlation was found between outcome and living conditions, age, vaccination status (unvaccinated versus one or more vaccines administered), or severity of clinical signs. However, of the vaccinated cats, none had received a vaccine later than 12 weeks of age as a kitten. Nonsurvivors had significantly lower leukocyte and thrombocyte counts at presentation compared with survivors. The relative risk of death for patients with <1,000/μL leukocytes was 1.77 times as high as in patients with a leukocyte count of 1,000–2,500/μL (P= .038), and 1.85 times as high as in patients with >2,500/μL leukocytes (P= .001). The likelihood of a fatal outcome was higher when serum albumin concentration was <30 g/L or serum potassium concentration <4 mmol/L. Conclusions and Clinical Importance: Vaccination strategies that do not include vaccination of kittens beyond 12 weeks of age may not be adequate to prevent panleukopenia. Leukopenia, thrombocytopenia, hypoalbuminemia, and hypokalemia are negative prognostic factors in cats with panleukopenia.     

Chemotactic responses of neutrophils in cats with spontaneous feline infectious peritonitis

The culture supernatant of peritoneal exudate cells (PEC) from cats with effusive feline infectious peritonitis (FIP) was chemotactic for peripheral blood neutrophils (PBN) from healthy cats, magnitude of the chemotactic activity being approximately 10-fold lower than that in zymosan-activated fresh serum of healthy cats (ZAS). The migration profile of PBN from healthy cats was slightly different between the PEC culture supernatant and ZAS. These findings suggest that the chemotactic activity detected in the PEC culture supernatant is distinct from that in ZAS. The chemotactic responses of PBN from FIP cats to ZAS were reduced, as compared with that from healthy controls. In contrast, the neutrophil chemotactic response and sensitivity to the PEC culture supernatant in FIP cats were not remarkably different from those in healthy controls. Furthermore, the chemotactic responsiveness of PEC from FIP cats to ZAS was slightly different from that of PEC to the PEC culture supernatant. These results suggest that neutrophils from FIP cats have altered reactivities against these chemoattractants.     

Retrospective analysis of seizures associated with feline infectious peritonitis in cats

Seizures have been reported frequently in feline infectious peritonitis (FIP) but have not been studied in detail in association with this disease. The purpose of this study was to perform a retrospective analysis of neurological signs in a population of 55 cats with a histopathologically confirmed neurological form of FIP. Seizure patterns were determined and it was attempted to relate occurrence of seizures with age, breed, sex and neuropathological features. Fourteen cats had seizure(s), while 41 cats had no history of seizure(s). Generalised tonic-clonic seizures were seen in nine cats; and complex focal seizures were observed in four patients. The exact type of seizure could not be determined in one cat. Status epilepticus was observed in one patient but seizure clusters were not encountered. Occurrence of seizures was not related to age, sex, breed or intensity of the inflammation in the central nervous system. However, seizures were significantly more frequent in animals with marked extension of the inflammatory lesions to the forebrain (P=0.038). Thus, the occurrence of seizures in FIP indicates extensive brain damage and can, therefore, be considered to be an unfavourable prognostic sign.     

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.     

Risk factors for feline infectious peritonitis in Australian cats

The objective of this study was to determine whether patient signalment (age, breed, sex and neuter status) is associated with naturally-occurring feline infectious peritonitis (FIP) in cats in Australia. A retrospective comparison of the signalment between cats with confirmed FIP and the general cat population was designed. The patient signalment of 382 FIP confirmed cases were compared with the Companion Animal Register of NSW and the general cat population of Sydney. Younger cats were significantly over-represented among FIP cases. Domestic crossbred, Persian and Himalayan cats were significantly under-represented in the FIP cohort, while several breeds were over-represented, including British Shorthair, Devon Rex and Abyssinian. A significantly higher proportion of male cats had FIP compared with female cats. This study provides further evidence that FIP is a disease primarily of young cats and that significant breed and sex predilections exist in Australia. This opens further avenues to investigate the role of genetic factors in FIP.     

A review of coronavirus infection in the central nervous system of cats and mice

Feline infectious peritonitis (FIP) is a common cause of death in cats. Management of this disease has been hampered by difficulties identifying the infection and determining the immunological status of affected cats and by high variability in the clinical, pathological, and immunological characteristics of affected cats. Neurological FIP, which is much more homogeneous than systemic effusive or noneffusive FIP, appears to be a good model for establishing the basic features of FIP immunopathogenesis. Very little information is available about the immunopathogenesis of neurologic FIP, and it is reasonable to use research from the well-characterized mouse hepatitis virus (MHV) immune-mediated encephalitis system, as a template for FIP investigation, and to contrast findings from the MHV model with those of FIP. It is expected that the immunopathogenic mechanisms will have important similarities. Such comparative research may lead to better understanding of FIP immunopathogenesis and rational prospects for management of this frustrating disease.     

猫传染性腹膜炎病毒核衣壳蛋白的表达及间接ELISA法的建立

本研究对猫传染性腹膜炎病毒（FIPV）N蛋白的编码基因进行克隆和原核表达,并在纯化重组N蛋白的基础上,建立了FIPV抗体间接ELISA检测方法。研究结果显示,该重组纯化的N蛋白具有良好的抗原反应性,可用于FIPV阳性血清的筛查,为我国出入境检疫部门监控FIPV疫情提供技术支撑。