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1.
Protection provided by live and inactivated virus vaccination against challenge with the virulent nephropathogenic infectious bronchitis virus (NIBV) strain PA/Wolgemuth/98 was assessed. Vaccinations with combinations of live attenuated strains Massachusetts (Mass) + Connecticut (Conn) or Mass + Arkansas (Ark) were given by eyedrop to 2-wk-old specific-pathogen-free leghorn chickens. After live infectious bronchitis virus (IBV) vaccination, some chickens at 6 wk of age received an injection of either an oil emulsion vaccine containing inactivated IBV strains Mass + Ark or an autogenous vaccine prepared from NIBV PA/Wolgemuth/98. Challenge with PA/Wolgemuth/98 was given via eyedrop at 10 wk of age. Serum IBV enzyme-linked immunosorbent assay antibody geometric mean titers (GMTs) after vaccination with the combinations of live attenuated strains were low, ranging from 184 to 1,354, prior to NIBV challenge at 10 wk of age. Both inactivated vaccines induced an anamnestic response of similar magnitudes with serum GMTs of 6,232-12,241. Assessment of protection following NIBV challenge was based on several criteria virus reisolation from trachea and kidney and renal microscopic pathology and IBV-specific antigen immunohistochemistry (IHC). Live attenuated virus vaccination alone with combinations of strains Mass + Conn or Mass + Ark did not protect the respiratory tract and kidney of chickens after PA/Wolgemuth/98 challenge. Chickens given a live combination vaccination of Mass + Conn and boosted with an inactivated Mass + Ark vaccine were also susceptible to NIBV challenge on the basis of virus isolation from trachea and kidney butshowed protection on the basis of renal microscopic pathology and IHC. Live IBV-primed chickens vaccinated with an autogenous inactivated PA/Wolgemuth/98 vaccine had the highest protection against homologous virulent NIBV challenge on the basis of virus isolation.  相似文献   

2.
Chicken embryos were inoculated with 8 different strains of infectious bronchitis virus (IBV) representing 7 different serotypes at 17 days of embryonation. At 2 and 5 days postinfection (dpi), tissues were collected for in situ hybridization using an antisense digoxigenin-labeled riboprobe corresponding to the sequence of the mRNA coding for the membrane protein. Extensive antigen staining in the cytoplasm of epithelial cells in the trachea, lung, bursa, and intestine was detected at 2 dpi with all 8 strains of IBV. At 5 dpi, little or no positive staining was observed in these tissues. However, tubular cells of the kidney showed multifocal positive staining with the Wolgemuth strain-, Gray strain-, JMK strain-, and Mass41 strain-infected chickens. No viral RNA was detected in the spleen at any time point. The results demonstrated strict epitheliotropic nature and wide tissue tropism of strains of IBV in the chicken embryo and the universality of our riboprobe. In situ hybridization with this probe will be useful for understanding the tissue tropism and the pathogenesis of IBV in vivo.  相似文献   

3.
The pathogenesis of infectious bronchitis in 4-week-old chickens was studied following administration of Australian T strain of IBV by the aerosol, conjunctival, intranasal, in-contact and drinking water routes.
Infected birds showed similar patterns of clinical signs, gross and histopathological lesions. While the birds infected by the aerosol route had earlier and slightly more severe respiratory tract disease it was concluded that the pathogenesis of infectious bronchitis virus nephritis was not significantly influenced by the route used to infect the birds.
In a second experiment, pathological changes produced in chickens infected with Australian S, A, A3 and T strains of IBV were compared in 18-day-old chickens infected by the aerosol route and housed in cold and warm environments. All 4 strains produced respiratory reactions and kidney lesions, and these changes were more severe and of longer duration in both respiratory tract and kidneys in the birds housed in a cold environment than those receiving supplementary heat.
The viruses differed in their virulence for the trachea and kidney and the effect of a virus on the respiratory trace was independent of the effect of that virus on the kidney.  相似文献   

4.
5.
Virus was recovered from the faeces of chickens infected at three or four weeks of age for more than 20 weeks after infection with commercial vaccines or with the T strain of avian infectious bronchitis virus (IBV). Virus was not recovered from the trachea, liver, spleen, bursa or kidneys of T strain infected birds longer than 29 days after infection at which point IBV was recovered from the bursa of a single infected bird. In a subsequent experiment IBV was recovered from the caecal lymph nodes and faeces of one of five birds 14 weeks after infection with a commercial vaccine but no virus was isolated from the trachea, kidneys, duodenum, bursa, ovaries or testes of any of the five birds at this time.  相似文献   

6.
One IBV isolate, SC021202, was isolated from the kidneys of the infected young chickens by inoculating embryonated eggs, and its morphology, physiochemical and haemagglutonating properties were detected. Virulence of the isolate SC021202 was determined with specific pathogen-free (SPF) chicken inoculation. Nucleotide acid sequence of S1 gene of the isolate SC021202 was further sequenced and analysed. The physiochemical and morphological properties of the isolate SC021202 were in accordance to that of typical infectious bronchitis virus (IBV). In a pathogenicity experiment, the clinical signs and related gross lesions resembling those of field outbreak were reproduced and the virus isolate SC021202 was re-isolated from the kidneys of the infected chicken. Sequence data demonstrated that the full length of the amplified S1 gene of the isolate SC021202 was composed of 1931 nucleotides, coding a polypeptide of 543 amino acid residues. Compared with IBV strains from GenBank, the nucleotide and deduced amino acid sequence of S1 gene of the isolate SC021202 shared 60.0-91.4% and 49.1-88.9% identities, respectively. A nucleotide fragment of 'CTTTTTAATTATACTAACGGA' was inserted at nucleotide site 208 in the S1 gene of the isolate. These results indicated that IBV isolate SC021202 was a new variant IBV isolate and responsible for field outbreak of nephritis.  相似文献   

7.
Infectious bronchitis virus (IBV) Cal99 variant was isolated from the kidneys of seven 2-5-mo-old game chickens with nephritis and respiratory disease. IBV Cal99 variant is usually associated with respiratory disease in broiler chickens in California. Macroscopically, the majority of the birds had moderately to severely enlarged and mottled pale kidneys, with increased urates in the ureters. Microscopically, most of the birds had acute nephrosis and interstitial nephritis. The birds also had sinusitis, tracheitis, bronchopneumonia, airsacculitis, salivary gland adenitis, and lymphoid depletion in the thymus and bursa of Fabricius. Immunohistochemistry was strongly positive for IBV antigen in the cytoplasm of tubular epithelial cells in the kidneys and also in the epithelium of the respiratory tract, salivary glands, proventriculus, intestine, and bursa of Fabricius. Infectious bronchitis virus was isolated from the trachea, lungs, kidneys, and cecal tonsils. Sequencing of the hypervariable region of the S1 gene of the kidney IBV isolate, designated IBV/CA99variant/07, revealed that the virus was 98% homologous to the Cal99 serotype of IBV.  相似文献   

8.
A model system was used to study infectious bronchitis virus (IBV) and Mycoplasma synoviae (MS) interaction. The system involved exposure of chickens to IBV, followed by exposure to MS 2-5 days later. The chickens were subjected to a cold environment (10 +/- 2 C) for 3 weeks starting one day before MS exposure. Under these conditions, differences in the capacity of various strains of IBV to exacerbate MS airsacculitis was demonstrated. Exposure to IBV field isolates generally resulted in more air-sac lesions than did higher-egg-passaged laboratory strains and vaccine strains. Use of lower-egg-passaged vaccines resulted in a higher incidence of airsacculitis than did higher-egg-passaged vaccines. When chickens were IBV-vaccinated before being used in the model system, the incidence of airsacculitis was lowered, even though the chickens became infected by the challenge virus. Vaccination of MS-free chickens with IBV had no effect on airsacculitis incidence when MS exposure occurred after the vaccine reaction was past.  相似文献   

9.
Nephropathogenic infectious bronchitis (NIB) was diagnosed in 28 infectious bronchitis virus (IBV)-vaccinated commercial chicken flocks in Pennsylvania from December 1997 to July 2000. Early dinical signs were increased flock mortality and urinary water loss (polyuria and pollakiuria) leading to wet litter. Daily mortality ranged from 0.01% in layers to 2.45% in broilers, with total broiler mortality as high as 23%. Severe renal swelling and accumulation of urates in the tubules were commonly seen. Visceral gout and urolithiasis were less frequently observed. Histopathologic changes included characteristic tubular epithelial degeneration and sloughing with lymphoplasmacytic interstitial nephritis. Minimal respiratory disease signs were noted in broilers. Egg production and shell quality declined in layers. Confirmatory diagnosis of NIB was made by IBV antigen-specific immunohistochemical staining of the renal tubular epithelium and virus isolation. Sequencing of the S1 subunit gene of 21 IBV isolates showed the NIB outbreak to be associated with two unique genotypes, PA/Wolgemuth/98 and PA/171/99. The cases from which the genotypes were isolated were clinically indistinguishable. The NIB viruses were unrelated to previously recognized endemic strains in Pennsylvania and were also dissimilar to each other. Genotype PA/Wolgemuth/98 was isolated almost exclusively during the first 14 mo of the outbreak, whereas PA/171/99 was recovered during the final 18 mo. The reason for the apparent replacement of PA/Wolgemuth/98 by PA/171/99 is not known.  相似文献   

10.
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.  相似文献   

11.
单抗免疫过氧化物酶技术检测鸡传染性支气管炎病毒   总被引:11,自引:3,他引:8  
以抗鸡传染性支气管病毒(IBV)核衣壳蛋白(N)的单抗株6DH8作为一抗,以辣根过氧化物酶标记的羊抗鼠IgG作为二抗,建立了检测石蜡切片中IBV抗原的单抗免疫过氧化物酶技术(Mc-IP),并对人工攻毒鸡及临床IBV感染疑似鸡进行了检测。在IBVM41株人工攻毒鸡,用该技术于1~12d从气管、2~7d从肾脏可以检测到IBV抗原,阳性染色集中于气管粘膜上皮细胞及肾小管上皮细胞胞浆;临床疑为IBV感染的病鸡,以Mc-IP技术和单抗免疫荧光试验(Mc-IFA)同时进行检测,结果阳性率分别为90.3%及83.9%。  相似文献   

12.
Naqi S  Gay K  Patalla P  Mondal S  Liu R 《Avian diseases》2003,47(3):594-601
Avian infectious bronchitis virus (IBV) causes a highly contagious and economically significant disease in chickens. Establishment of a carrier state in IBV infection and the potential for the persistent virus to undergo mutations and recombination in chicken tissues have important consequences for disease management. Nevertheless, whether chickens can maintain persistent IBV infection in the absence of reinfection from exogenous sources or the presence of antibody in the host can modulate virus persistence remains unclear. Indeed, whether or not IBV genome can undergo genetic changes during in vivo infection has not been demonstrated experimentally. In the present study, IBV shedding and tissue persistence were monitored in individual chickens maintained under strict isolation that precluded reinfection from exogenous sources. In the first of two experiments, intranasal exposure of 6-wk-old antibody-free chickens to IBV vaccine virus resulted in intermittent shedding of the virus from both trachea and cloaca of individual birds for up to 63 days. Also, the virus was recovered from the internal organs (spleen, gonad, kidney, lung, cecal tonsil, and cloacal bursa) of six of eight birds killed at various intervals between 27 and 163 days postinoculation (DPI). In the second experiment, IBV exposure of 1-day-old maternal antibody-positive chicks led to periodic virus shedding from the trachea and cloaca in all chickens until 77 days; however, internal organs (lungs and kidneys) of only one of seven birds (killed at 175 DPI) were virus positive, suggesting that presence of antibody at the time of infection protects internal organs from IBV infection. When the lung and kidney isolates of IBV from the latter experiment were compared with the parent-vaccine virus, no changes in their antigenicity, tissue tropism, or the nucleotide sequence of the S1 glycoprotein gene were observed. These findings indicate that, unlike the mammalian coronaviruses, propensity for frequent genetic change may not be inherent in the IBV genome.  相似文献   

13.
试验旨在探讨不同来源的传染性支气管炎病毒(Infectious bronchitis virus,IBV)诱导SPF鸡发病的免疫机制。选用140只1日龄SPF白来航鸡,随机分为4组,3组攻毒组通过滴鼻点眼途径分别接种鸡源IBV强毒株、鸡源IBV弱毒株和野鸡源IBV毒株3个毒株,对照组以同种方式接种等量灭菌的磷酸盐缓冲液。在感染后12 h、36 h、72 h、7 d和14 d,每组随机选取5只进行剖检,并分别采集法氏囊、肾脏和气管组织,剩余鸡用于观察临床症状、发病及死亡情况。应用实时荧光定量PCR检测攻毒后不同时间点采集的各组织中IBV的病毒载量、Toll样受体(Toll-like receptors,TLRs)及部分细胞因子(白细胞介素(interleukin,IL)和干扰素(interferon,IFN))表达量的变化。结果显示,感染不同来源IBV毒株之后仅鸡源IBV强毒株感染组SPF鸡出现抑郁、翅膀下垂、甩头等典型的临床症状,且在感染后5~10 d共有7只死亡,死亡率为20%。病理剖检发现,感染鸡源IBV强毒株的鸡肾脏肿大、尿酸盐沉积和有花斑样病变,而感染野鸡源IBV毒株、鸡源IBV弱毒株和对照组的鸡无明显的眼观病变。实时荧光定量PCR结果显示,在鸡源IBV强毒株组的法氏囊、肾脏和气管3个组织中均检测到病毒。对照组和野鸡源IBV毒株组中均未检测到病毒,鸡源IBV弱毒株组只在部分组织中检测到病毒。在感染后72 h,鸡源IBV强毒株组与其他各组相比,TLR1、TLR2、TLR3、TLR5、TLR7和TLR15基因在法氏囊中的表达量均显著升高(P<0.05),IL-6和IFN-β参与更强烈的抗病毒免疫反应;在感染后7 d,鸡源IBV弱毒株组与其他各组相比,肾脏中TLR2、TLR3、TLR15、TLR21、IL-6和IL-18基因表达量均显著升高(P<0.05)。野鸡源IBV感染后36 h法氏囊组织中IFN-γ基因表达量显著上调(P<0.05)。综上所述,3个IBV毒株中仅鸡源IBV强毒感染引起SPF鸡典型临床发病症状与可视组织病变,且可提高SPF鸡组织中免疫相关因子的基因表达量。本研究结果揭示,不同来源的IBV对SPF鸡的不同致病性与其感染诱导的免疫反应不同有关。  相似文献   

14.
Chickens infected with infectious bronchitis virus (IBV) and infectious bursal disease virus (IBDV) commonly develop secondary infection of the respiratory tract with Escherichia coli, resulting in significant economic losses. To understand the host factors that may contribute to the E. coli infection, we investigated macrophage-mediated E. coli phagocytosis, intracellular bacterial killing, and development of opsonizing antibody in previously uninfected chickens and in those infected with IBV, IBDV, and IBDV plus IBV. Macrophages from the peripheral blood and the respiratory tracts of chickens infected with IBV or IBDV plus IBV efficiently performed in vitro phagocytosis of E. coli in the presence of positive-control serum (i.e., E. coli antiserum produced in normal chickens). Those macrophages also had adequate bactericidal activity, indicating that IBV and IBDV infections had not affected their phagocytic activity or bactericidal function. The phagocytic activity of macrophages remained unaffected (P < 0.05) when the positive-control serum was replaced with E. coli antiserum produced in chickens infected with IBV alone. However, when E. coli antisera raised in IBDV-infected and, especially, that produced in IBDV plus IBV-infected chickens were supplemented, the percentage of phagocytosis and number of bacteria ingested per phagocyte were significantly (P < 0.05) less. These results indicate that although IBDV alone has the potential to markedly reduce opsonizing ability of antibody, this effect is significantly (P < 0.05) exacerbated by IBV infection.  相似文献   

15.
Attenuation of avian infectious bronchitis virus by cold-adaptation.   总被引:2,自引:0,他引:2  
Avian infectious bronchitis virus (IBV) Arkansas-type DPI strain was passaged 10 times in specific-pathogen-free (SPF) chicken embryos incubated at 28 C and 37 C. Virus grown at 28 C acquired cold-adapted (CA) and temperature-sensitive (TS) characteristics based on more-rapid growth at 28 C and a reduced ability to grown at 41 C, respectively, compared with non-cold-adapted (non-CA) virus grown at 37 C. The pathogenicity and immunogenicity were determined for CA and non-CA IBV in 1-day-old SPF chickens following intratracheal inoculation. The percentage of CA IBV-vaccinated chicks exhibiting respiratory disease exceeded 30% on only 1 day postinoculation (PI) (day 5 PI), compared with 8 days (days 2-9 PI) for birds given non-CA IBV. Mortality was 0% for CA IBV-vaccinated chickens and 6% for non-CA virus-vaccinated chickens. Microscopically, both CA and non-CA IBV caused diffuse tracheal deciliation, although mucosal hyperplasia, necrosis, and heterophil infiltration were more severe with non-CA IBV. Virus was reisolated from kidneys of chickens given CA IBV, suggesting the loss of the TS property. The instability of the TS property was confirmed by growth of the reisolated virus at 41 C. Both CA and non-CA viruses induced complete protection against homologous challenge virus infection of the upper respiratory tract.  相似文献   

16.
Infectious bronchitis (IB) is a worldwide disease affecting chickens of all ages and causing important economic losses in poultry industry. Despite being one of the predominant IB virus (IBV) serotype in several European countries, slightly is known about pathogenesis and pathogenicity of Italy 02 serotype. In this study chicks and old hens were infected by oculo-nasal route with Italy 02 serotype. Clinical signs, gross and microscopic findings were evaluated, viral nucleic acid detection was assessed by in situ hybridization (ISH) in several tissues and viral RNA was detected by RT-PCR in trachea, kidney and nasal and cloacal swabs. Italy 02 serotype was demonstrated to cause severe respiratory and renal damage in one-day old chicks but not in adult hens in which only respiratory disease and drop in egg production was observed. The use of ISH technique demonstrated the presence of viral RNA in nasal turbinates prior to trachea, but more consistent and longer replication periods in enterocytes of lower gastrointestinal tract. The detection of viral nucleic acid in gut by RT-PCR was consistent and more persistent viral shedding was detected in faeces than in nasal exudates. We describe a complete update of IBV distribution in tissues by the use of molecular techniques and we also provide and in-depth pathological characterization of the new Italy 02 IBV serotype. Furthermore, new data about IBV pathogenesis essential in field control is afforded.  相似文献   

17.
K Yagyu  S Ohta 《Avian diseases》1990,34(2):246-252
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.  相似文献   

18.
Yan F  Zhao Y  Yue W  Yao J  Lihua L  Ji W  Li X  Liu F  Wu Q 《Avian diseases》2011,55(3):451-458
Between 2006 and 2009, seven strains of infectious bronchitis (IB) virus (IBV) were isolated from vaccinated chicken flocks on different chicken farms in China. The pathogenic characters of seven IBV strains were assessed. Each of the seven strains was infective to the test chickens and could induce an immune response. The results from chicken embryo cross-neutralization assays showed that these strains were antigenically distinct from classic IBV strains of H120, M41, Conn, and Gray. Compared to H120 vaccine strain, point mutation, short insertion, and deletion occurred at many positions in the S1 protein of the seven strains. Five of the seven strains had the motif (HRRRR), which was identical to that of the epidemic IBV strains in China. Two new motifs (HRLRR and RRIRR) emerged in the isolated strains. The homology of the nucleotide and amino acid sequences of the S1 gene among the seven isolates was 81.7%-99.7% and 79.0%-99.4%, respectively. These seven strains were also genetically different from the vaccine strains and non-China IBV strains but closely related to large numbers of Chinese strains. The seven isolates and 36 reference IBV strains were clustered into six distinct groups (I-VI). The seven strains were categorized into groups I, II, and III, forming a big phylogenetic branch, which is closely related to Chinese IBVs, whereas the vaccine strains belonging to group VI are genetically distant from groups I, II, and III. The results from this study indicate that different IBV strains cocirculate in the chicken population in China.  相似文献   

19.
20.
To monitor the existence of avian pathogens in laying chicken flocks, specific pathogen-free (SPF) chickens were introduced into two layer farms and reared with laying hens for 12 months. SPF chickens were bled several times after their introduction and examined for their sero-conversion to avian pathogens. As a result, antibodies to eight or ten kinds of pathogens were detected in SPF chickens on each farm. Antibodies to infectious bronchitis virus (IBV), avian nephritis virus, Mycoplasma gallisepticum and M. synoviae were detected early within the first month. Antibody titer to IBV suggested that the laying chickens were infected with IBV repeatedly during the experiment on both farms. However, antibodies to infectious bursal disease virus and 6 pathogens were not detected.  相似文献   

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