Vaccination of the young kitten

This paper draws together those diseases of the cat where vaccination is either being practised in the UK or overseas, or is currently being considered. In the UK, vaccination is routinely carried out for feline panleucopenia, feline viral rhino-tracheitis (FVR), and feline calicivirus infection, and in quarantine, cats are also vaccinated against rabies. In the USA and some other countries, vaccination is also carried out against feline leukaemia virus infection, feline Chlamydia psit-taci infection and routinely against rabies. Attempts are also being made to develop vaccines for feline infectious peritonitis (FIP), although there are a number of problems associated with the development of a successful FIP vaccine which will be referred to later. Factors important in prevention and control of the three diseases feline panleucopenia, FVR, and feline calicivirus infection for which vaccination in the UK is commonly practised will be discussed. For each disease, some background information on the virus and the epizootiology of the disease is given, which it is hoped will lead to greater understanding of the principles involved in prevention and control. A few points will then be made about vaccination in some of those diseases where vaccines are being developed or where it is carried out in other countries.     

Cytokines and anti-cytokine therapy: clinical potential for treatment of feline disease

Cytokines are soluble proteins produced by nucleated cells throughout the body. They have wide ranging effects on cell growth and differentiation, mediating immune responses, haemopoiesis and tissue repair. Advances in recombinant DNA technology have led to a vast increase in knowledge of their biological properties and subsequently their use in human clinical trials. The use of human cytokines in feline medicine has been of limited success as the action of cytokines is often species restricted or their activity may be neutralized due to antibody formation. Recently, however, many feline cytokines have been cloned which raises the possibility of their future use in the management and prevention of feline disease. Ultimately, they may find widespread clinical uses including the treatment of cancer, cytopenias and viral infections and as vaccine adjuvants.     

The natural history of the major feline viral diseases

This paper discusses factors that are important in the natural history of five major feline viral diseases, namely, feline panleucopenia, feline viral rhinotracheitis, feline caliciviral disease, feline leukaemia virus infection, and feline infectious peritonitis. Each disease is considered in terms of the properties and infectivity of the infecting agent, the sources of infectious virus, the mode of transmission of the disease, and the methods by which the agent persists in the cat population. Finally, each disease is discussed in terms of immunity and the role of vaccination. All these factors affect the balance of the virus-host relationship and are thus directly relevant to the epizootiology of these diseases and their control.     

Intranasal vaccination against upper respiratory tract disease (U.R.D.) in the cat—I. Virological and serological observations in cats suffering from U.R.D.

A number of cat colonies in The Netherlands, in which upper respiratory tract disease (U.R.D.) was endemic, were examined for the presence of feline herpes virus (H) and feline calici virus (C) infections. In total 108 cats were examined. In 59% of the cases feline calici virus was isolated and feline herpes virus in 39% of the cases. Mixed infections were found in 26% of the cats. The virus isolates were all neutralised by anti-sera against attenuated strains of feline herpes virus and feline calici virus which are incorporated in a newly developed combined C-H vaccine against U.R.D. in cats. Intranasal application of this vaccine induced a distinct increase in resistance against experimental challenge with virulent C and H, as soon as 24 hours after vaccination.     

猫泛白细胞减少症疫苗的研究进展

猫泛白细胞减少症是一种由猫泛白细胞减少症病毒引起的,猫科动物常见的接触性传染病,临床发病率和死亡率均较高,疫苗免疫接种是预防和控制该病最经济、最直接的措施.然而,国内几无商业化宠物疫苗,特别是猫用疫苗,国外疫苗进口困难,亟需开发新型宠物用高效疫苗.对国内外猫泛白细胞减少症疫苗现状及不同类型疫苗(灭活疫苗、减毒活疫苗等)...     

Isolation and classification of feline picornavirus and herpesvirus in Denmark

Seventeen viral isolates cytopathic for kitten kidney cells were isolated from 23 cats with symptoms of the respiratory disease feline viral rhinotracheitis or feline influenza. Five of these are classified tentatively as calicivirus, a member of the Picornavirus group, and 12 have the properties of the herpesvirus. Classification is based on the cytopathic effect in cell cultures and physico-chemical characteristics.The five isolates which are classified tentatively as calicivirus produced a quick cytopathic effect without formation of intranuclear inclusion bodies. The isolates were resistant to chloroform, were not inhibited by IDU, were labile at pH 4 and were not stabilized against thermal inactivation by molar MgCl₂. The 12 isolates which seem to belong to the herpesvirus produced intranuclear inclusion bodies in cell cultures. They were sensitive to chloroform, and multiplication was inhibited by IDU. Antisera were produced by inoculating rabbits with calicivirus and cats with herpesvirus. The five isolates classified tentatively as calicivirus belong in one serotype, and the 12 isolates which seem to belong to the herpesvirus also belong in one serotype.Keyword: feline Picornavirus, feline calicivirus, feline herpesvirus, feline viral rhinotracheitis, feline influenza, isolation, classification, Denmark     

FCV-VBS isolated from cats with typical symptoms caused VSD in experimental cats

Commercially available vaccines have been used widely to prevent feline calicivirus infection (FCI). However, with their widespread use, field strains, which are weakly cross-reactive with the live-virus vaccine strain F9, have posed the problem of vaccine breakdown. Recently the existence of FCV—associated virulent systemic disease (VSD) has been published. But their molecular diversity, antigenic mutations and physicochemical property have not been sufficiently clarified. Thus, we experimentally gave the vaccine breakdown strain (VBS) H10 to cats that had been inoculated with an F9 live vaccine. After the administration of strain H10, vaccinated cats (1 through 4) had no respiratory symptoms, whereas the non-vaccinated cat 5 showed clinical symptoms such as a fever of over 40°C, loss of vitality, decreased appetite, diarrhea, and nasal discharge after receiving strain H10, and died. Lethal FCV is rare, and may be a virulent systemic disease (VSD)—inducing strain. This is the initial report on VSD in Japan. It has been reported that symptoms of VSD were similar in vaccinated and nonvaccinated cats on experimental infection. However, no VSD-like symptoms developed, and the incidence of the disease varied depending on the presence or absence of vaccination, suggesting that there are two mechanisms of vaccine breakdown: one is associated with the vaccine immunity level, and the other is not. The characteristics of the VBS revealed were: (1) the duration of virus excretion was short when the originally carried antibody titer before virus challenge was high, (2) the excreted viral molecular species varied daily, not being limited to a specific species with time, and (3) the acquired physicochemical properties did not persist, and altered daily. FCV-VBS alters the molecular species and physicochemical properties daily due to the reduction of host immunity, which may lead to VSD.     

猪繁殖与呼吸综合征疫苗研究进展

猪繁殖与呼吸综合征是一种引起母猪繁殖障碍和新生仔猪呼吸道症状及高死亡率的传染病。在世界包括中国在内的各养猪国家广泛流行,造成严重经济损失,受到国内外学者的高度重视,对此病的研究特别是对其疫苗的研究正日益受到关注。文章就猪繁殖与呼吸综合征病毒的灭活疫苗、弱毒疫苗和基因工程疫苗的研究进展做了详细的阐述。     

Clinical and immunological responses of cats to feline herpesvirus type 1 infection

Cats which were challenged with feline herpesvirus type 1 developed clinical signs typical of feline viral rhinotracheitis whether or not they had been vaccinated against the disease. However, the clinical disease was less severe and of shorter duration in the vaccinated cats. After challenge, feline herpesvirus type 1 was recovered from the nostrils, oropharynx and peripheral blood leucocytes. Leucocytosis, primarily a neutrophilia, occurred initially in all the cats and was followed after clinical recovery by a mild lymphocytosis. Intradermal skin testing with feline herpesvirus type 1 and cell control antigens produced a positive delayed type skin reaction. Histology of the affected skin 72 hours after injection showed cellular infiltration, predominantly with eosinophils and neutrophils. The severity of the reaction was greater and more prolonged in the skin of the ear than in the skin of the abdomen.     

Long-term immunity in cats vaccinated with an inactivated trivalent vaccine.

OBJECTIVE: To evaluate duration of immunity in cats vaccinated with an inactivated vaccine of feline panleukopenia virus (FPV), feline herpesvirus (FHV), and feline calicivirus (FCV). ANIMALS: 17 cats. PROCEDURE: Immunity of 9 vaccinated and 8 unvaccinated cats (of an original 15 vaccinated and 17 unvaccinated cats) was challenged 7.5 years after vaccination. Specific-pathogen-free (SPF) cats were vaccinated at 8 and 12 weeks old and housed in isolation facilities. Offspring of vaccinated cats served as unvaccinated contact control cats. Virus neutralization tests were used to determine antibody titers yearly. Clinical responses were recorded, and titers were determined weekly after viral challenge. RESULTS: Control cats remained free of antibodies against FPV, FHV, and FCV and did not have infection before viral challenge. Vaccinated cats had high FPV titers throughout the study and solid protection against virulent FPV 7.5 years after vaccination. Vaccinated cats were seropositive against FHV and FCV for 3 to 4 years after vaccination, with gradually declining titers. Vaccinated cats were protected partially against viral challenge with virulent FHV. Relative efficacy of the vaccine, on the basis of reduction of clinical signs of disease, was 52%. Results were similar after FCV challenge, with relative efficacy of 63%. Vaccination did not prevent local mild infection or shedding of FHV or FCV. CONCLUSIONS: Duration of immunity after vaccination with an inactivated, adjuvanted vaccine was > 7 years. Protection against FPV was better than for FHV and FCV. CLINICAL IMPLICATIONS: Persistence of antibody titers against all 3 viruses for > 3 years supports recommendations that cats may be revaccinated against FPV-FHV-FCV at 3-year intervals.     

Combined administration in a single injection of a feline multivalent modified live vaccine against FHV, FCV, and FPLV together with a recombinant FeLV vaccine is both safe and efficacious for all four major feline viral pathogens

Nobivac Tricat, a lyophilised trivalent modified live attenuated vaccine is routinely used to protect cats against three commonly diagnosed feline viral pathogens namely herpesvirus, calicivirus and panleukopenia virus. The recognition of feline leukaemia virus (FeLV) as an important viral pathogen has prompted the development of an efficacious liquid recombinant subunit FeLV vaccine (p45 envelope protein). Lyophilised Tricat vaccine was dissolved in the liquid FeLV vaccine and no detectable deleterious effect on the titre of any of the live virus components was observed after 2h incubation. In vivo studies where the vaccines were mixed in the same syringe prior to inoculation showed no alteration to the safety profile assessed by repeat and overdose studies. Serological comparisons of the modified live viral antibody titres showed no evidence of reduced responses following administration of the mixed products. Challenge studies using pathogenic herpesvirus and FeLV revealed no difference in the degree of clinical protection. This paper shows that neither safety nor efficacy is adversely affected as a result of mixing the two vaccines.     

The Efficacy of Two Commercial Feline Rhinotracheitis-Calicivirus-Panleukopenia Vaccines

The efficacy of two commercial feline vaccines was determined by challenging vaccinated and unvaccinated cats sequentially with a virulent feline calicivirus and rhinotracheitis virus. Serological responses to these viruses as well as to panleuk openia virus were also measured. Results show significant protection and satisfactory serological responses are conferred by both vaccines. One vaccine showed significant superiority in protection against feline viral rhinotracheitis.     

新城疫基因工程疫苗的研究与应用进展

新城疫是当今世界上最严重的家禽传染病之一，特别是对养鸡业可造成重大经济损失，被世界动物卫生组织（OIE）列为必须报告的传染病。新城疫的主要防控手段仍是免疫接种，虽然传统的灭活疫苗和弱毒疫苗在疫病的控制中发挥了巨大作用，但存在着毒力返强、散毒和免疫期短等问题，不利于疫病的控制和消灭。论文论述了国内外应用现代分子生物技术对新城疫亚单位疫苗、重组活载体疫苗、DNA疫苗、新城疫病毒载体疫苗的研究和应用情况，展示了基因工程疫苗良好的应用前景。     

The effectiveness of paramunization for the control of feline coryza]

20 cats in a cat home were treated prophylactically and therapeutically with Baypamun HK. The animals were allocated into three groups as described. 7 freshly admitted clinically healthy cats were treated prophylactically on day 1, 2 and 9 with 1 ml Baypamun HK (group I). 7 cats, who already were allocated for one year in the home and were sick of the feline respiratory disease complex were treated as described for group I (group II). 6 further cats, who also showed symptoms of the feline respiratory disease complex and had stayed for one year in the home were treated with physiol.saline solution according to group I (group III). From all cats blood samples were taken at day 1, 3, 10 and 17. The blood samples were checked for antibodies against feline calicivirus (FCV), feline herpesvirus (FHV), panleukopenia virus (PLV), feline peritonitis virus (FIPV) and feline immunodeficiency virus (FIV). Also the occurrence of the feline leukemia virus (FeLV) was evaluated. The cellular immunity was evaluated by means of the lymphocyte transformations test (LTT), nitroblue-tetrazolium reduction test (NBT) and cytochrome C-reduction test (CRT). Mean value and standard deviation was calculated from the results. The significance was determined by the t-test. The animals were examined clinically daily for 20 days for the feline respiratory disease complex. When necessary, the animals were treated by homeopathic and antibiotic products. At the time of admission to the home all cats were or had been treated with an attenuated panleukopenia vaccine. The serologic parameters were not influenced in the cats of group I.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antibody response to an inactivated vaccine for rhinotracheitis, caliciviral disease, and panleukopenia in nondomestic felids

The efficacy of an inactivated vaccine for the prevention of feline viral rhinotracheitis (FVR), feline caliciviral disease (FCVD), and feline panleukopenia (FPL) was tested in 27 nondomestic adult felids from 7 species. The vaccine was given IM at the standard domestic cat dose in 19 animals and double this dose in 8 others. The animals were vaccinated either 1, 2, or 3 times. Serum-neutralization (SN) antibodies to FVR (mean SN titer, 23) developed in all 15 animals that were previously seronegative, and SN antibodies to FCVD (mean SN titer, 11) developed in 19 of 21 animals that were previously seronegative. There was no significant increase of SN antibody titers by doubling the vaccine dose or by administering a 3rd vaccination. The optimal response could be obtained by using the domestic cat vaccination protocol of a single dose given twice, 4 weeks apart. The critical evaluation of the SN antibody titer for FPL was complicated by preexisting titers to FPL from previous vaccinations, but in 23 animals the titers became higher, whereas they remained unchanged in only 4 animals. The persistence of the SN titers was evaluated 7 to 9 months later and found to be satisfactory for FVR (mean SN titer, 18) FCVD (mean SN titers, 43) and FPL (mean SN titer, 517). Enhanced persistence of titer could not be demonstrated by doubling the dose or administering a 3rd vaccination.     

FIP: a novel approach to vaccination. Proceedings from the 2nd International FCoV/FIP Symposium, Glasgow, 4-7 August 2002

Feline infectious peritonitis (FIP) is a fatal disease of cats. Early attempts at vaccination have been unsuccessful, some even serving to exacerbate the disease through antibody-dependent enhancement. Replication-incompetent feline foamy virus (FFV) transducing vectors are being developed as potential vaccine agents, into which immunogenic fragments of feline coronavirus (FCoV) proteins will be inserted. To use a recombinant viral vector to express FCoV proteins, the agent chosen should be apathogenic and replication incompetent within the host following gene delivery. Spumaviruses confer several advantages over the more traditionally explored retroviral vectors. Stable helper cell line clones have been established by transfection of CRFK cells with FFV tas and assessed using beta-galactosidase assays, PCR, immunofluorescence and western blotting. The generation of infectious virions using these cell lines has been investigated using tas-deleted FFV vectors containing the enhanced green fluorescent protein (eGFP) cassette.     

Evaluation of a feline viral rhinotracheitis-feline calicivirus disease vaccine.

An attenuated respiratory disease vaccine against feline viral rhinotracheitis (FVR) and feline calicivirus (FCV) disease was evaluated for safety and efficacy in specific-pathogen-free cats. Twenty cats were vaccinated twice intramuscularly, with 28 days between vaccinations. Ten unvaccinated cats were used as contact controls. Adverse effects were not noticed after vaccination, and the vaccinal virus did not spread to contact controls. Arithmetical mean serum-neutralizing titers against vaccinal FCV strain F9 and challenge FCV strain 255 were 1:13 and 1:15 at 28 days after the 1st inoculation. These titers increased to 1:45 and 1:196 after the 2nd inoculation. After challenge exposure of vaccinated cats to virulent FCV 255 virus, mean titers increased to 1:129 and 1:865, respectively for F9 and 255 viruses. The F9 postchallenge mean titer for vaccinated cats was 21.5 times higher than that for the 8 contact controls that survived challenge exposure. The arithmetical mean serum neutralizing titer for FVR was low (1:2) after the 1st vaccination, but increased to 1:35 after the 2nd vaccination. Challenge exposure to virulent FVR virus resulted in a marked anamnestic immune response (mean titer of 1:207, compared with 1:12 for contact controls). In general, vaccinated cats remained alert and healthy after challenge exposure with FCV-255, whereas unvaccinated contact control cats developed definite signs of FCV disease, including central nervous system (CNS) depression (6 of 10) and dyspnea indicative of pneumonia (5 of 10). Two controls died of severe pneumonia. A mild fibrile response was detected in 28% of vaccinated cats, compared with a more severe febrile response in 78% of control cats. Some vaccinated cats developed minute lingual ulcers that did not appear to be detrimental to the health of the cat. After FVR challenge exposure, vaccinated cats were free of serious clinical signs. Five of 18 vaccinated cats had mild signs of FVR, including an occasional sneeze, low temperature, and mild serous lacrimation for 1 or 2 days. Contact controls developed definite clinical signs of FVR. The combined FVR-FCV vaccine appears to be safe and reasonably efficacious. Vaccination against FCV disease and FVR should be part of the routine feline immunization program.     

猪繁殖与呼吸综合征疫苗研制的研究进展

猪繁殖与呼吸综合征是一种引起母猪繁殖障碍和新生仔猪呼吸道症状及高死亡率的传染病,在全世界蔓延流行,2006年在中国又变异为高致病性猪繁殖与呼吸综合征并造成严重经济损失。自20世纪80年代末首次在美国发现该病至今已有20余年,该病尚未有特效的治疗药物,疫苗免疫是防控该病的重要措施之一,国内外学者高度重视其疫苗的研究,并取得了较大的进展。笔者着重阐述近些年来猪繁殖与呼吸综合征活疫苗、灭活疫苗及基因工程疫苗的研究进展。     

水貂细小病毒性肠炎弱毒疫苗的研究

用猫泛白细胞减少症病毒(FPV)弱毒作为制苗毒种,经CRFK细胞培养15代,使其滴度稳定在10~(5.0)～10~(5.0)TCID_(50)/0.03mL之间.经4代猫体返祖试验证明,该弱毒无返祖现象.10倍免疫剂量的水貂安全试验证明,该弱毒毒力稳定,对水貂无感染性.用FPV弱毒4～15代病毒研制成功的水貂肠炎弱毒疫苗,各项试验证明,该苗安全可靠,免疫剂量为10~(3.0)×1mL,免疫效果好,保护率在95%以上,免疫期6个月以上.     

Three-year duration of immunity in cats following vaccination against feline rhinotracheitis virus, feline calicivirus, and feline panleukopenia virus

Forty-two seronegative cats received an initial vaccination at 8 weeks of age and a booster vaccination at 12 weeks. All cats were kept in strict isolation for 3 years after the second vaccination and then were challenged with feline calicivirus (FCV) or sequentially challenged with feline rhinotracheitis virus (FRV) followed by feline panleukopenia virus (FPV). For each viral challenge, a separate group of 10 age-matched, nonvaccinated control cats was also challenged. Vaccinated cats showed a statistically significant reduction in virulent FRV-associated clinical signs (P = .015), 100% protection against oral ulcerations associated with FCV infection (P < .001), and 100% protection against disease associated with virulent FPV challenge (P < .005). These results demonstrated that the vaccine provided protection against virulent FRV, FCV, and FPV challenge in cats 8 weeks of age or older for a minimum of 3 years following second vaccination.