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.     

Treatment of cats with feline infectious peritonitis

Feline infectious peritonitis (FIP) infection resulting in clinical signs is invariably fatal despite clinical intervention. As FIP is an immune-mediated disease, treatment is mainly aimed at controlling the immune response triggered by the infection with the feline coronavirus (FCoV). Immune suppressive drugs such as prednisone or cyclophosphamide may slow disease progression but do not produce a cure. In nearly every published case report of attempted therapy for clinical FIP, glucocorticoids have been used; there are, however, no controlled studies that evaluate the effect of glucocorticoids as a therapy for FIP. Some veterinarians prescribe immune modulators to treat cats with FIP with no documented controlled evidence of efficacy. It has been suggested that these agents may benefit infected animals by restoring compromised immune function, thereby allowing the patient to control viral burden and recover from clinical signs. However, a non-specific stimulation of the immune system may be contraindicated as clinical signs develop and progress as a result of an immune-mediated response to the mutated FCoV.     

Evaluation of immunity to feline infectious peritonitis in cats with cutaneous viral-induced delayed hypersensitivity

Delayed-type hypersensitivity (DTH)-like reactions to feline infectious peritonitis (FIP) virus (FIPV) were induced in the skin of nine cats that were asymptomatic after a previous challenge-exposure with FIPV. Four of the nine previously challenge-exposed cats were negative for virus-neutralizing antibodies against FIPV at the time of intradermal (ID) testing for DTH. Two other cats tested for DTH when acutely ill with clinical FIP did not have cutaneous DTH responses to FIPV. Gross skin reactions to FIPV injected ID were observed in six of nine asymptomatic cats (67%) at postintradermal inoculation hours (PIH) 24, 48, and/or 72. The reactions consisted of focal, 1-5-mm to 2.5-cm diameter indurated or semi-firm, nonerythematous, slightly raised nodules. Microscopically, DTH-like reactions were observed in biopsies taken from the FIPV-inoculated skin of asymptomatic cats at PIH 24 to 72. The lesions consisted of perivascular and diffuse dermal infiltrations by macrophages, lymphocytes, and polymorphonuclear leukocytes (PMN). The dermal infiltrates, which were maximal at PIH 48 or 72, were predominantly mixed inflammatory cells (five of nine cats) or PMN (four of nine cats) at PIH 24, but later were predominantly mononuclear cells (six of nine cats) or mixed inflammatory cells (two of nine cats) at PIH 72. Five of nine cats (56%) with positive DTH skin responses had increased survival times after lethal ID challenge-exposure with FIPV compared to mean survival times in FIPV-naive, non-immune control cats that were DTH-negative when ID challenge-exposed. Four of nine DTH-positive cats (44%) resisted an ID challenge-exposure dose of FIPV that was fatal in both control cats, and two of the four remaining DTH-positive cats survived a third challenge-exposure with highly lethal doses of FIPV given intraperitoneally. Four of the six DTH-positive cats (67%) that died after re-challenge and were necropsied had lesions of noneffusive FIP, suggesting that cellular immunity may also be involved in the pathogenesis of noneffusive disease, whereas both control cats and both DTH-negative cats with clinical disease succumbed to effusive FIP. Seemingly, DTH responses to FIPV can be associated with an increased level of resistance to disease; however, this state of immunity is variable and apparently can be lost with time in some cats.     

Humoral immune responses of cats to feline infectious peritonitis virus infection.

Immunoperoxidase antibody (IPA) method as a titrating method of feline infectious peritonitis (FIP) virus (FIPV) was developed for titrating antibody to FIPV (IPA-titer). By this method the immune responses of the cats that had been infected with FIPV, were traced. The infected cats could be grouped into three types by their immune response to FIPV and clinical appearances. Type I cats lived for a long time, formed a major group among infected cats, had 160 to 1 x 10(4) IPA-titers, and showed healthy appearances without any changes both on autopsy and histopathologically. From among type I cats, type II cats appeared sporadically with rapid elevation of IPA titers to 3.2 x 10(5) and showing clinical signs of FIP, and died. Type III cats lived healthily for a long time with gradual elevation of IPA-titers to a plateau of about 1 x 10(5), then showed neuronal disorder of hind leg paralysis with the descending IPA-titers to 2 x 10(4), and died. Thus, typical FIP appeared as a hyper-immune disease. Other related problems are discussed.     

Virus shedding and immune responses in cats inoculated with cell culture-adapted feline infectious peritonitis virus

Eight specific pathogen-free cats were inoculated orally or parenterally with a cell culture-adapted strain of feline infectious peritonitis virus (FIPV). Faeces and oropharyngeal swabs were monitored daily for infectious virus by inoculation of feline embryo lung cells. Virus was recovered from both sites for approximately 2 weeks after inoculation, before clinical signs of disease developed. Peripheral blood lymphocytes collected from these cats were tested in an in-vitro blastogenic assay using concanavalin A (con A) and FIPV antigen. All cats showed a profound suppression of the response to con A which only recovered to pre-inoculation levels in 2 cats, one of which survived. These 2 cats also responded to FIPV antigen on the 21st day after infection, the greater response being in the survivor. The other cats, surviving 16-18 days, developed no response to FIPV antigen. Antibody titres, measured by immunofluorescence and by virus neutralization, rose rapidly to very high levels in all cats, regardless of the route of inoculation.     

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.     

Enhanced platelet reactivity in cats experimentally infected with feline infectious peritonitis virus

Platelet function was evaluated in six specific-pathogen-free cats prior to and following intraperitoneal inoculation with feline infectious peritonitis virus (FIPV). By 4 days post-inoculation, platelet samples from five of six cats responded with irreversible platelet aggregation to threshold concentrations of adenosine diphosphate (ADP). This was accompanied by enhanced platelet 14C-serotonin release (greater than 10%) in two cats. Compared to one of six baseline samples, five of five post-inoculation samples exhibited microaggregate formation in response to 20 microM epinephrine. Enhanced platelet 14C-serotonin release did not accompany these responses. Enhanced platelet responses to ADP and epinephrine were also observed on day 11 post-inoculation and day 16 (when one cat died) or 21 (the end of the study). Platelet 14C-serotonin release in response to 20 microM epinephrine increased markedly in three of five cats on day 21. Enhanced collagen-induced platelet responses were not demonstrated. Although the mechanism for the enhanced platelet responses observed on day 4 was unknown, a direct effect on the virus on platelets, mononuclear inflammatory cells, and endothelial cells must be considered.     

Laboratory changes consistent with feline infectious peritonitis in cats from multicat environments

The present study describes the prevalence of haematological and electrophoretic changes consistent with the diagnosis of feline infectious peritonitis (FIP) in cats without FIP living in six multicat environments with different prevalence of FIP and of other diseases. The results allow designing haematological and electrophoretic profiles typical of each group, most likely depending on the management and on the health status of the group rather than on the prevalence of FIP. In fact, many cats from the colonies with open management and frequent outbreaks of infectious diseases other than FIP had one or more haematological and/or electrophoretical changes consistent with FIP, compared with the reference ranges. In the case of non-specific clinical signs such as fever or neurological signs because of diseases other than FIP, these cats would be erroneously considered as affected by FIP and euthanasized. The use of internal ranges designed on the basis of repeated samplings from non-symptomatic cats allows avoiding these misinterpretations. Results from cats with symptoms consistent with FIP living in the same colonies were also compared with both the reference ranges and the internal ones: such a comparison demonstrated that the use of internal ranges rarely affected the possibility to correctly diagnose the disease in cats with symptoms suggestive of FIP.     

Priapism in a castrated cat associated with feline infectious peritonitis

This report describes a case of feline infectious peritonitis (FIP) in a castrated cat which first presented with the unusual sign of priapism. Laboratory examinations showed increased serum protein content and decreased albumin/globulin ratio. Serum electrophoresis revealed increased alpha 2- and gamma-globulin content. One month after the first examination, the cat died. At necropsy, histopathological evaluation of organs showed inflammatory granulomatous lesions compatible with non-effusive FIP and coronavirus-specific polymerase chain reaction confirmed the diagnosis. FIP antigen was demonstrated immunohistochemically in penile tissue.     

Prevalence of feline coronavirus types I and II in cats with histopathologically verified feline infectious peritonitis

Feline coronaviruses (FCoV) vary widely in virulence causing a spectrum of clinical manifestations reaching from subclinical course to fatal feline infectious peritonitis (FIP). Independent of virulence variations they are separated into two different types, type I, the original FCoV, and type II, which is closely related to canine coronavirus (CCV). The prevalence of FCoV types in Austrian cat populations without FIP has been surveyed recently indicating that type I infections predominate. The distribution of FCoV types in cats, which had succumbed to FIP, however, was fairly unknown. PCR assays have been developed amplifying parts of the spike protein gene. Type-specific primer pairs were designed, generating PCR products of different sizes. A total of 94 organ pools of cats with histopathologically verified FIP was tested. A clear differentiation was achieved in 74 cats, 86% of them were type I positive, 7% type II positive, and 7% were positive for both types. These findings demonstrate that in FIP cases FCoV type I predominates, too, nonetheless, in 14% of the cases FCoV type II was detected, suggesting its causative involvement in cases of FIP.     

Papular cutaneous lesions in a cat associated with feline infectious peritonitis

A 7-month-old-intact male domestic shorthair cat was presented with fever, anterior uveitis in the right eye and respiratory distress when handled. These signs along with mild changes in serum protein levels and the exclusion of other potential causes were suggestive of feline infectious peritonitis (FIP). As the disease progressed, more clinical signs consistent with FIP, including renal involvement and later pleural effusion, became evident. Non-pruritic cutaneous lesions, characterized by slightly raised intradermal papules over the dorsal neck and over both lateral thoracic walls, were recognized at the end stage of the disease. The identification of papules in well-haired skin was difficult, and clipping of the fur facilitated their detection. Definitive diagnosis of FIP was made by histopathology and by immunohistochemical demonstration of coronavirus antigen in macrophages within kidney and skin lesions. The case was classified as a mixed form of FIP. Recognition of associated cutaneous lesions may facilitate a diagnosis of FIP in suspicious cases.     

146例猫传染性腹膜炎的临床变化与转归

为了解猫传染性腹膜炎(FIP)的临床特征,指导临床应用,调查了北京市芭比堂连锁动物医院2018年收诊的猫科病例。收集了146例自然发生的猫FIP的病例信息,包括年龄、性别、品种,以及临床症状、实验室和影像学特征、药物治疗及临床转归,并对其发生率、复发率、转归率进行比较分析。结果显示:2岁(84%)、发烧(60%)和胸/腹水(65%)病例显示很高的FIP发生率;11%的FIP猫表现眼部症状,如葡萄膜炎和角膜后沉积物;血液或胸、腹水白球比0.6(51%)、单纯胆红素血升高(13%)、急性期反应蛋白异常升高(13%);血液或胸腹水猫冠状病毒(FCoV)检测阳性(38%)、高抗体滴度(2%)、超声肾脏髓质缘征(32%)等有助于诊断FIP;在146例FIP猫中,缓解率34%,复发率2%,死亡率64%,在40例FIP猫中,用抑制FCoV复制剂(GC376、GS44152)治疗,其缓解率达70%。     

Attempted immunisation of cats against feline infectious peritonitis using canine coronavirus

Specific pathogen free kittens were vaccinated with an unattenuated field isolate of canine coronavirus (CCV) either by aerosol or subcutaneously, and received boosting vaccinations four weeks later. Aerosolisation elicited a homologous virus-neutralising (VN) antibody response that increased steadily over a four-week period and levelled off one to two weeks after revaccination. The initial aerosolised dose produced an asymptomatic infection with excretion of CCV from the oropharynx up to eight days after vaccination; virus shedding was not detected, however, after the second inoculation. Cats vaccinated subcutaneously developed low VN antibody titres after the first CCV dose and experienced a strong anamnestic response after the second dose. Neutralising antibody titres then levelled off one to two weeks after revaccination at mean values somewhat lower than in cats vaccinated by aerosol. CCV was not isolated from the oropharynx after either subcutaneous dose. Four weeks after CCV boosting inoculations, vaccinated cats and sham-vaccinated control cats were divided into three subgroups and challenged by aerosol with the virulent UCD1 strain of feline infectious peritonitis virus (FIPV UCD1) at three different dosage levels. Five of six cats (including sham-vaccinated controls) given the lowest challenge dose showed no signs of disease, while all other cats developed lesions typical of feline infectious peritonitis (FIP). The five surviving cats developed FIP after subsequent challenge with a fivefold higher dose of FIPV. Thus heterotypic vaccination of cats with CCV did not provide effective protection against FIPV challenge.     

Feline infectious peritonitis with spinal cord involvement in two cats.

Two cats from the same household had posterior paresis and hypergammaglobulinemia. Histologic evaluation of the spinal cords revealed a pyogranulomatous reaction consistent with that reported for feline infectious peritonitis.     

Hydrocephalus associated with the noneffusive form of feline infectious peritonitis.

The noneffusive form of feline infectious peritonitis was diagnosed in a cat with progressive vestibular and cerebellar deficits. Histopathologic findings included generalized pyogranulomatous lesions of the meningeal, ependymal, and subependymal areas of the brain. Hydrocephalus was associated with the lesions.     

Potentiation of platelet responses in vitro by feline infectious peritonitis virus

The effect of feline infectious peritonitis virus (FIPV) on platelet aggregation and 14C-serotonin release induced by threshold levels of four agonists (adenosine diphosphate [ADP], collagen, arachidonic acid, and epinephrine) was examined in vitro in ten specific-pathogen-free cats. Purified suspensions of FIPV added to stirred platelet suspensions (virus to platelet ratio equal to 1:320) 1 minute prior to the addition of agonist potentiated the ADP-induced aggregation response by greater than 100% in seven cats. Platelet 14C-serotonin release was increased by greater than 100% in four cats. Collagen-induced platelet aggregation was enhanced in ten cats while collagen-induced 14C-serotonin release was enhanced in eight cats. Potentiation of arachidonic acid-induced platelet aggregation was observed in three cats, two of which demonstrated enhanced platelet 14C-serotonin release. Although epinephrine-induced platelet aggregation was enhanced in five cats, the samples displayed only fine microaggregates. Enhanced 14C-serotonin release from platelets in response to epinephrine was not demonstrated. Interaction with the outer platelet membrane and internalization of viral particles within the surface-connected open canalicular system were demonstrated by electron microscopy within 5 minutes of the addition of virus to platelet suspensions with or without added agonists. Decreasing the virus concentration by ten- or one hundred-fold abolished the potentiating effect observed previously, while increasing the concentration tenfold resulted in direct platelet activation in the absence of agonist.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term follow-up study of cats vaccinated with a temperature-sensitive feline infectious peritonitis vaccine.

The long-term safety of a temperature-sensitive feline infectious peritonitis (FIP) vaccine was evaluated. Five hundred eighty-two healthy cats of various age groups were vaccinated with 2 doses of the vaccine. Seventy-eight percent, or 453 cats, were available for follow-up. The mean follow-up period was 541 days. At the end of the follow-up period, 427 cats (94%) were alive. FIP was not diagnosed in any cat during the follow-up period, but 1 cat died of FIP after completion of the follow-up period. Fifty cats (11%) presented with a problem during the follow-up period, but there were typical of those seen in a feline practice. The temperature-sensitive FIP vaccine appears to be safe for use in the general cat population. It does not appear to sensitize cats to develop FIP, nor do there appear to be any other systemic problems associated with use of the vaccine.