Vaccine efficacy against Ontario isolates of infectious bronchitis virus

Infectious bronchitis (IB) is an economically important viral disease with worldwide distribution. Every country with an intensive poultry industry has infectious bronchitis virus (IBV). The virus rapidly spreads from bird to bird through horizontal transmission by aerosol or ingestion. Sentinel bird studies were carried out in southern Ontario and IBV has been isolated from layer flocks. Genetic analysis of the S1 region of the strains showed that they were not vaccine related. The pathogenicity of selected Ontario variants of IBV isolates was studied and the subsequent work was to determine the degree of protection against field isolates provided by a commonly used vaccine MILDVAC-Ma5 in Ontario. The protection was evaluated by challenging immunized chickens with the respiratory (IBV-ON1) and nephropathogenic (IBV-ON4) viruses. The mean vaccine efficacy for IBV-ON1 was 66.7% indicating that a Massachusetts serotype vaccine would provide some protection against IBV field isolates.     

鸡传染性支气管炎病毒分型研究进展

鸡传染性支气管炎严重危害养禽业,其病原传染性支气管炎病毒血清型/基因型复杂,不同血清型/基因型之间免疫交叉保护效果差。IBV毒株的分型对于实施有效的疫病控制、病原研究、流行病学调查及研究病毒的演化意义重大。文章就IBV分型的最新研究进展进行综述,为IBV相关研究提供参考。     

鸡传染性支气管炎病毒致病机理的研究进展

鸡传染性支气管是由鸡传染性支气管炎病毒引起鸡的一种急性高度接触性呼吸道传染病,由于病毒血清型较多,易于发生变异而难以免疫预防,成为养鸡业发展的重大阻力。文章就该病毒的致病机理方面的研究情况做一综述,为防制鸡传染性支气管炎提供科学依据。     

IBV分离株部分S1蛋白基因的序列分析

参考GenBank上的IBVS1基因序列,自行设计合成了一对跨幅约0.6kb的引物,RT-PCR对6株IBV分离株的S1基因进行扩增。序列分析显示,这些病毒从时间、空间和组织嗜性都没有明显的规律可循。2株从传染性腺胃炎病鸡中获得病毒(ZC4-3株和DB239-1株)属于既不同于国内其他分离毒株,又不同于国际参考毒株的独立一群。通过对IBV的分析,认为现流行的IBV已发生了很大的变异,分别利用嗜肾性、嗜呼吸道性和嗜腺胃性的毒株研制疫苗,对我国IBV的防疫十分重要。     

鸡传染性支气管炎病毒辅助蛋白研究进展

鸡传染性支气管炎(Infectious bronchitis,IB)是由鸡传染性支气管炎病毒(Infectious bronchitis virus,IBV)引起的高度接触性传染病,给养殖生产造成巨大的经济损失.近年来随着反向遗传操作技术的发展,国内外学者在分子生物学水平对IBV基因组结构与功能开展了深入研究,在IBV...     

First evidence of the emergence of novel putative infectious bronchitis virus genotypes in Cuba

The emergence of new infectious bronchitis virus (IBV) genotypes or serotypes along with the poor cross-protection observed among IBV serotypes have complicated the avian infectious bronchitis (IB) control programs in different geographic regions. In Cuba, the lack of genetic information regarding IBV and the increasing epidemiological importance of this virus in Cuban chicken flocks demand further characterization of IBV isolates. In the present work, studies of genetic diversity and phylogenetic relationships among recent IBV isolates from Cuban chicken flocks showing respiratory disorders were performed. Two putative genotypes genetically different to the Massachusetts genotype H120 strain used in the Cuban vaccination program were found in the flocks assessed. In addition, a potential nephropathogenic IBV isolate was found by first time in Cuba.     

Serological comparison and antigenic relationships of seven serotypes of infectious bronchitis virus using the hemagglutination-inhibition test

The antigenic relationships, antigenic spectrum, and immunogenicity of seven isolates of infectious bronchitis virus (IBV) were examined using the hemagglutination-inhibition (HI) test. Because there was a discontinuity of antigenic relationships and a high degree of cross-reactivity among serotypes of IBV in cross-hemagglutination-inhibition tests, the range of antigenic spectrum used to group the serotypes with the HI test should be wider than the limits suggested by the plaque-reduction test. The HI test may provide valuable information in monitoring the immune status of a flock following vaccination when the area has a history of infectious bronchitis infection. It may also be used as a rapid diagnostic test if a flock is experiencing an outbreak of a disease caused by emergence of a new type of IBV. Interpretation of HI titers in evaluating immune status of chickens following infection with IBV depends on further cross-challenge and cross-protection studies of various types of IBV.     

鸡传染性支气管炎病毒免疫机制和免疫预防研究进展

由鸡传染性支气管炎病毒（Infectious bronchitis virus,IBV）引起的鸡传染性支气管炎（Infectious bronchitis,IB）是高度传染的全球性鸡病之一,严重危害养鸡业。IBV众多的血清型及其基因组的不断变异,给IB的免疫防控带来很大的困难。IBV主要侵害鸡的呼吸系统、泌尿生殖系统和消化系统,病鸡出现呼吸困难、产蛋下降、肾炎和腺胃炎等症状和病变。IBV的特点是变异频繁,血清型复杂,所致疾病的临床表现差异很大。因此,IB已成为养禽业最难控制的疫病之一。鸡对IBV的免疫机制是国内外研究的热点之一。传统疫苗已不能完全保护免疫鸡群,开发IBV基因工程疫苗,从主要免疫原性蛋白的良好表达到免疫策略的不断完善,已成为未来预防IB的趋势。     

Genetic diversity of avian infectious bronchitis virus isolates in Korea between 2003 and 2006

Thirty-three field isolates of avian infectious bronchitis virus (IBV) were recovered from commercial chicken flocks in Korea between 2003 and 2006 and were characterized phylogenetically by nucleotide sequence analysis of the IBV S1 gene hyper-variable region. Our phylogenetic analysis revealed that recent field isolates of IBV formed at least three distinct phylogenetic types, including K-I, K-II, and K-III. K-I type IBV consisted of indigenous, 13 IBV isolates which evolved from the Kr-EJ/95 strain and then separated into the lineages of type K-Ia and type K-Ib. K-II type IBV isolates (n = 19) were closely related to nephropathogenic IBV variants from China and Japan. The K-III type isolate (Kr/D064/05), first identified by this study, was closely related to enteric IBV variants from the Chinese strains that cause proventriculitis. Sequence comparisons showed amino acid differences of >27.5% between IBV types. The molecular epidemiologic characteristics of IBV field isolates are briefly discussed.     

鸡传染性支气管炎病毒分子生物学研究进展

鸡传染性(IBV)支气管炎是由冠状病毒属传染性支气管炎病毒引起的高度接触性传染病。此病在世界各地均有发生,危害严重,给全球养禽业造成巨大的经济损失。IBV血清型较多且抗原易发生变异,肾型和肠型变异株的出现,给该病的诊断和防治造成了困难。近年来国内外学者对其研究不断深入,特别在病毒基因组的组成、病毒结构蛋白的功能、病毒的转录合成机制、病毒粒子的组装等方面取得了重要进展,所有这些成果为IBV预防与控制提供了科学依据。     

鸡传染性支气管炎病毒分型与诊断防治的研究进展

鸡传染性支气管炎是由鸡传染性支气管炎病毒引起的一种急性、高度接触性传染性疾病。以张口呼吸、气管啰音、咳嗽、肾脏病变为主要临床症状,可引起鸡的饲料报酬率降低,蛋鸡产蛋数量和蛋的品质下降。IBV的特点是高频变异,血清型众多,导致疾病的临床和病理变化复杂多样,由于其变异株出现比较快,毒株之间交叉保护力差,给IB的诊断和防治带来了较大困难。从IBV的分型、检测技术、综合防治方面对该病的研究进展进行了综述。     

鸡传染性支气管炎病毒受体研究进展

鸡传染性支气管炎是一种世界性分布的严重影响养鸡业的高度接触性传染病,其病原是一种最早发现的冠状病毒鸡传染性支气管炎病毒(IBV)。IBV入侵细胞的受体是目前IBV研究中的热点之一。已知IBV囊膜上的纤突蛋白(S)是宿主组织和细胞嗜性及致病性的主要决定因素,S蛋白通常断裂为S1和S2两部分,S1与宿主细胞膜上的细胞受体相结合,在S2的作用下病毒囊膜与宿主细胞膜融合,IBV与受体结合之后于中性或微碱性pH时发生构象改变,从而获得病毒进入宿主细胞的能力。对于IBV的受体研究主要集中于IBV可能使用的几种功能性受体,包括氨肽酶N、唾液酸、硫酸乙酰肝素等。     

Viral pathogenesis of a nephrotropic infectious bronchitis virus isolated from commercial pullets.

Infectious bronchitis was diagnosed in 3-to-4-week-old pullets from an outbreak in a commercial flock in California. The disease was characterized by head swelling, watery discharge from the eyes and nostrils, and urates in kidneys. Mortality ranged from 1.8% to 12.5% per week. The isolation of a coronavirus from a suspension of pooled kidneys from clinically ill chickens at the fifth passage in 10-day-old chicken embryos, gross and histologic renal lesions, and seroconversion by enzyme-linked immunosorbent assay in inoculated birds suggested that the virus isolated was a nephrotrophic strain of infectious bronchitis virus (IBV). The virus isolate was found to be a previously unrecognized serotype, based on virus neutralization tests performed in embryonated chicken eggs. Nephropathogenicity of the IBV isolate was confirmed by inoculation of the viral isolate into specific-pathogen-free chicks and demonstration of renal lesions. The isolation of nephrotropic strains of IBV has not been reported previously from poultry in California.     

Detection of infectious bronchitis virus antigen from experimentally infected chickens by indirect immunofluorescent assay with monoclonal antibody

Infectious bronchitis virus (IBV) was detected by indirect immunofluorescent assay with a monoclonal antibody (MAb-IFA). The monoclonal antibody was specific for the nucleocapsid protein of IBV strain M41. The MAb-IFA clearly detected IBV with high specificity in infected chicken kidney cells. The assay furthermore detected IBV in tracheal smears and sliced tracheas from experimentally infected chickens. The positive reaction was found to be longer than that in the virus recovery test. These results indicate that MAb-IFA is a useful method for the detection of IBV from chickens suspected to have infectious bronchitis.     

鸡4种病毒抗原液的浓缩及其四联油佐剂灭活苗的研制

本研究通过超滤浓缩技术对鸡新城疫病毒、传染性支气管炎病毒、产蛋下降综合征病毒和传染性法氏囊病病毒的尿囊液进行了10倍或10倍以上的浓缩处理，并按一定的比例配比研制成四联油乳剂灭活疫苗，对鸡的最小免疫剂量是0.25ml，免疫接种二周后，鸡新城疫和产蛋下降综合征病毒的HI抗体效价分别达到8log     

IgM responses in chicken serum to live and inactivated infectious bronchitis virus vaccines.

Intramuscular (i.m.) administration of infectious bronchitis virus (IBV) oil-emulsion vaccine (OEV) to IBV-primed or unprimed chickens resulted in the production of zero or minimal concentrations of IBV-specific IgM in the serum, as measured by enzyme-linked immunosorbent assay of gel chromatography fractions. Live-attenuated infectious bronchitis (IB) vaccine given i.m. or by eyedrop stimulated the production of IBV-specific IgM in similar amounts following inoculation by both routes. These levels were comparable to those found in earlier studies following intranasal inoculation with a virulent strain of IBV and confirm that the detection of IBV-specific IgM is a valuable aid to the diagnosis of recent infection. As expected, administration of live-attenuated IB vaccines i.m. or by eyedrop protected the respiratory tract against challenge with virulent virus 24 days later; however, OEV given i.m. did not.     

Optimization of parameters for detecting antibodies against infectious bronchitis virus using an enzyme-linked immunosorbent assay: temporal response to vaccination and challenge with live virus

Critical parameters affecting sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA) for avian infectious bronchitis virus (IBV) were evaluated and optimized. The use of purified IBV as antigen at 50 ng protein/well and high-ionic-strength serum dilution buffer has resulted in a test with minimal nonspecific binding of chicken immunoglobulins and very high sensitivity. Optimum conditions for serum dilution, conjugate dilution, and substrate incubation were determined for minimizing background and nonspecific reactions. The use of this test in a controlled challenge study with chickens vaccinated with live IBV demonstrated its effectiveness in monitoring circulating antibody levels to infectious bronchitis. The IBV ELISA, which is rapid, inexpensive, highly sensitive, and capable of handling very large numbers of samples, should provide the poultry industry with a reliable means for IBV flock monitoring.     

鸡肾型IBV的分离及其N基因的克隆与测序

通过病毒形态学观察、血凝试验、病毒干扰实验、动物回归实验等分离鉴定了1株鸡肾型传染性支气管炎病毒.利用RT-PCR技术对分离毒株的N基因进行了扩增,经克隆、序列测定和分析,证实分离株为肾型IBV.     

鸡传染性支气管炎M41毒株S1基因的克隆与真核表达研究

根据Genbank中公布的IBVS1基因序列 ,设计了一对引物 ,克隆出IBV强毒株M41的S1基因 ,基因大小为 1 .62kb ,导入真核表达载体系统pIRS1neo中 ,表达蛋白分子量为 61ku ,并具有中和活性。为今后开发鸡传染性支气管炎基因工程疫苗奠定了基础。     

鸡传染性支气管炎病毒SC株N基因序列测定与同源性分析

从我国四川省一疑似鸡传染性支气管炎(Avianinfectious bronchitisvirus,IB)的雏鸡病料中成功分离到一株鸡传染性支气管炎病毒(Infectious Bronchitis Virus,IBV),命名为SC。病毒经鸡胚传代、血凝试验监测和负染电镜检查证实为IBV。自接毒鸡胚尿囊液中提取RNA后应用反转录-聚合酶链反应(RT-PCR)扩增得到了IBVSC株mRNA6 cDNA(编码N蛋白)。应用DNAstar5．06,Clustal1．8分析软件将克隆测序的N蛋白基因与Genbank中11株国内外参考毒株进行序列比较分析和同源性分析,发现IBV SC株变异独特,明显不同于国内外参考毒株。