• Journal of Veterinary Science
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• v.22 no.4
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• pp.49.1-49.6
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• 2021

The S1 protein of the infectious bronchitis virus (IBV) is a major structural protein that induces the production of the virus-neutralization antibodies. The monoclonal antibody against the IBV M41 S1 protein was used as a target for biopanning. After three rounds of biopanning, randomly selected phages bound to the monoclonal antibody. Sequence analysis showed that the dominant sequence was SFYDFEMQGFFI. Indirect competitive enzyme-linked immunosorbent assay showed that SFYDFEMQGFFI is a mimotope of the S1 protein that was predicted by PepSurf. The mimotope may provide information for further structural and functional analyses of the S1 protein.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.127-136
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• 2019

Three strains of infectious bronchitis viruses (IBVs), designated VNUA3, VNUA8 and VNUA11, were isolated from diseased/infected chickens in Hanoi, Thainguyen, and Haiphong provinces of Vietnam. These birds had received a live IBV vaccination but still suffered from infectious bronchitis. VNUA3, VNUA8 and VNUA11 harbor cleavage sites (RRTGR, HRRRR, and HRRKR, respectively) within the S protein. A BLASTN search revealed that the S gene of VNUA3, VNUA8, and VNUA11 showed the highest nucleotide identity with those of IBV strains CK/Italy/I2022/13, CK/CH/LHLJ/08-6, and GX-NN120084, respectively. Phylogenetic analyses based on the S gene nucleotide sequences revealed that VNUA3, VNUA8 and VNUA11 clustered with Q1-like, QX-like and TC07-2-like genotypes, respectively, and were closely related to reference IBV strains from China. However, the Vietnam IBVs showed high divergence from vaccine strains 4/91 and Ma5, which are used in the Vietnamese farms from which the isolates were obtained. Taken together, these results indicate that at least three genotypes of IBV are circulating among chickens in North Vietnam. This is the first report of the molecular epidemiology of IBV in Vietnam.

• Korean Journal of Veterinary Research
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• v.63 no.4
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• pp.41.1-41.6
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• 2023

Many viruses can infect different types of birds, with poultry being the most susceptible. These viral diseases have a direct negative impact on the poultry industry, with significant economic losses. This study examined a group of the most important viruses that infect backyard chickens in 2 specific areas of Basrah Governorate, south of Iraq. The study analyzed avian influenza viruses (AIVs), Newcastle disease virus (NDV), and infectious bronchitis virus (IBV). Two hundred and ninety oropharyngeal swabs, 150 from Abu Al-Khasib and 140 from Shatt Al-Arab regions in the Basrah governorate, were obtained from backyard chickens with clear respiratory signs. The samples were subjected to viral RNA extraction, and the viral nucleic acids were detected using a reverse transcriptase polymerase chain reaction technique. The overall rate of viral infections was 74.8%, which varied depending on the type of virus: 15.8%, 31.3%, and 27.5% for AIV, NDV, and IBV, respectively. The NDV and IBV had much higher infection rates than that of AIV. In addition, the prevalence of AIV in the Shatt Al Arab district was significantly higher than in the Abul Khasib district. Moreover, there were no significant differences between the NDV and the IBV distributions in either of the targeted regions in this study.

• Journal of the korean veterinary medical association
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• v.46 no.8
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• pp.726-735
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• 2010

전염성기관지염 바이러스(infectious bronchitis virus: IBV), 조류 뉴모 바이러스(Avian pneumovirus: APV), 뉴캣슬병 바이러스 (Newcastle disease virus: NDV), 조류인플루엔자 바이러스(avian influenza virus: AIV) 전염성 후두기관염 바이러스 (infectious laryngotracheitis virus: ILTV)는 닭의 호흡기에 직접 감염하여 호흡기질환을 일으키는 대표적인 바이러스로 알려져 있다. 그 밖에 아데노바이러스(adenovirus)와 레오바이러스 (reovirus)도 닭의 상부호흡기에 침투하여 피해를 입히는 이차적 원인체로 작용할 수 있다. 이들중 APV와 ILTV는 닭의 호흡기도에 국한되어 증식하지만 IBV, NDV, AIV의 경우 호흡기도 이외의 장기에서 증식이 가능하여 그 피해가 다양하게 나타나 문제 시 되기도 한다 (예: 산란장기 및 신장 (IBV), 소화기 (NDV, IBV, AIV), 중추신경계 (NDV, AIV)). 이외에도 상당수의 감염성 질환이 닭의 호흡기에 영향을 미칠 수 있으나, 해당 농장의 호흡기 피해가 어떤 질병에 의한 것인지 명확히 파악하지 못한 채 단순 항생제 처방에만 의지하는 경우가 많은 것이 현실이다. 따라서 국내 양계농가에서 문제시되는 주요 호흡기 질병과 이들의 감수성을 증대시키는 요인을 파악하는 것이 필요하고, 호흡기 질병의 피해에 대한 재인식과 아울러 호흡기 질병 피해 감소를 위한 진단과 예방노력이 하루속히 정착되어야 할 것이다. 본지에서는 대표적인 호흡기 질병 세가지(전염성기관지염, 조류뉴모바이러스감염증, 뉴캣슬병)의 최근 발생동향과 그 대처방안에 대하여 소개하고자 한다.

• Journal of Veterinary Science
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• v.21 no.6
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• pp.76.1-76.13
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• 2020

Background: The predominant infectious bronchitis virus (IBV) strains detected in chickens in Malaysia are the Malaysian variant (MV) and QX-like, which are associated with respiratory distress, nephropathy, and high mortality. On the other hand, the antigenic relatedness and efficacy of IBV vaccines against these 2 field IBV strains are not well characterized. Objectives: This study aimed to determine the antigen relatedness and efficacy of different IB vaccine strains against a challenge with MV and QX-like strains. Methods: The antigen relatedness and the ability of different IB vaccine strains in conferring protection against MV and QX-like were assessed based on the clinical signs, macroscopic lesions, and ciliary activity. Results: The MV strain IBS037A/2014 showed minor antigenic subtype differences with the vaccine virus Mass H120 and 4/91 strains but showed major antigenic subtype differences with the K2 strain. The Malaysian QX-like strain IBS130/2015 showed major antigenic subtype differences with the MV strain IBS037A/2014 and the vaccine strains except for K2. Chickens vaccinated once with Mass (H120) or with non-Mass (4/91 and K2) developed antibody responses with the highest antibody titer detected in the groups vaccinated with H120 and 4/91. The mean ciliary activities of the vaccinated chickens were between 56 to 59% and 48 to 52% in chickens challenged with IBS037A/2014 and IBS130/2015, respectively. The vaccinated and challenged birds showed mild to severe lesions in the lungs and kidneys. Conclusions: Despite the minor antigenic subtype differences, a single inoculation with Mass or non-Mass vaccines could not protect against the MV IBS037A/2014 and QX-like IBS130/2015.

• Korean Journal of Veterinary Research
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• v.56 no.3
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• pp.189-192
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• 2016

The virus neutralization (VN) test was used to determine potency of the infectious bronchitis (IB) vaccine. The results of VN, hemagglutination inhibition (HI), and enzyme-linked immunosorbent assay (ELISA) were compared with those of the IBV M41. The $r^2$ values between VN and HI titers and the ELISA antibody titer were 0.8782 and 0.0336, respectively, indicating a high correlation between VN and HI, but not VN and ELISA. The Cohen's kappa coefficient between the VN titer of 2 $log_{10}$ and HI titer of 5 $log_2$ was 0.909. Our results showed that VN could be replaced with HI for testing the potency of IBV M41.

• Korean Journal of Veterinary Service
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• v.38 no.1
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• pp.51-56
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• 2015

Infectious bronchitis virus (IBV) causes an acute and highly contagious viral disease of chicken that is great economic losses to the poultry industry worldwide. Among the IBV structural proteins, the high rate spike glycoprotein S1 gene mutation and antigenic variant strains have been reported in many countries. During the years 2012~2014, 10 IBV strains were isolated from infected chicken farms distributed in provinces of Jeonbuk. Analysis of the S1 gene sequences amplified from 10 isolated strains with QX strains showed nucleotide homologies ranging from 96.5 to 95.4%. Phylogenetic analysis revealed that all strains were clustered into QX-like groups. This study suggests that QX-like IBVs are circulating in commercial chicken farms in Jeonbuk. Therefore, the continuing survellance is significantly important for prevention and control of BIV infection.

• Korean Journal of Veterinary Research
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• v.45 no.3
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• pp.405-410
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• 2005

To analyze and identify selected risk factors for infectious bronchitis virus (IBV) infection in the growing and laying period of laying-hen flocks, a longitudinal field study was conducted with 27 commercial flocks reared in three provinces of Korea during the period from May 2003 to April 2004. Using monitored data for IBV infection status among study flocks we computed the multivariate odds ratios (ORs) and their corresponding confidence intervals (CIs), and population attributable risks (PARs). Multivariate logistic regression showed significant risk increments for: continuous entry of chick (OR=1.9, 95% CI, 0.7-69.1) and operation years of the layer house greater than or equal to 5 years (OR=3.2, 95%CI, 1.6-389.9). No significant interaction was found between variables. The PAR suggested that continuous entry of chick (PAR=32%) and ${\geq}5years$ of house operation (PAR=84%) had the highest impacts on IB presence in laying-hen flocks under study. Of the two significant factors, however, operation year of the layer house lacks an easy applicability in preventing IB control strategies, and the possibility of confounder cannot be ruled out.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.503-515
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• 1989

Critical parameters affecting sensitivity and specificity of an enzyme-linked immunosorbent assay(ELISA) for detection of antibodies to avian infections bronchitis virus(IBV) were standardized. By adopting the optimized conditions an equation calculating ELISA antibody titers from the observations at single serum dilution was formulated. The purified antigen of IBV Mass-41 strain was dispensed into polystyrene microplate wells at a concentration of 300ng per well($100{\mu}l$) and the plates were coated by completey drying at $37^{\circ}C$. Diluted chicken serum and horseradish peroxidase conjugated goat anti-chicken IgG were added in order in $100{\mu}l$ volumes per well and allowed to react for 30 minutes each at room temperature. Just before use and after each reaction the plates were washed three times with distilled water. Finally o-phenylenediamine solution was added as an enzyme substrate. After incubation for another 15 minutes at room temperature absorbances were read at 492nm. Hyperimmune serum against Mass-41 strain was used as internal reference positive(IRP) serum. After repeated titration of IRP and negative serum, a constant titer of IRP was determined. Serum titrations were carried out for various sample sera together with IRP and negative sera and the observed titers of sample sera were corrected by reflecting the ratio between observed and constant titers of IRP serum. These corrected titers of the sample sera were plotted against sample/positive(S/P) OD ratios. All the OD's measured in the serum titrations were also corrected by substracting negative serum OD. The following equation was formulated from the above data; $Log_{10}$ ELISA titer=$5.568({\log}_{10}S/P)+4.161$ Thus it was possible to calculate ELISA titer by measuring absorbance at 1/400 single serum dilution. Titer measured by cross ELISA tests employing Mass-41 strain and three local IBV isolates were similar. These results suggest that the ELISA tests standardized in this study can be used for evaluating not only vaccinal immunity but also for infection status against fields IBV's.

• Journal of Veterinary Clinics
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• v.26 no.2
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• pp.134-137
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• 2009

Although there is circumstantial evidence that infectious bronchitis(IB) in the Korean layer industry has contributed to severe economic losses, the seroprevalence against IB virus(IBV) and risk factors associated with seropositivity are not well known. During May to October 2007, 820 blood samples were randomly collected from 41 laying hen flocks(20 birds in each flock) with $\geq$ 3,000 birds of 18 week of age or older in three provinces of Korea. The samples size was determined considering a flock-size range of 3,000-65,000 birds, an expected bird-level seroprevalence of $\geq$ 15%, and a 95% level of confidence. Serum samples were examined using a hemagglutination inhibition test for antibodies to IBV. The overall apparent flock-level seroprevalence was 46.3%(95% CI, 31.1-66.6) with no statistically significant differences among provinces(X=1.205, p>0.05). There were 19 positive flocks with one to eight seropositive birds, and 11 of these had one or two seropositive birds. None of the measured parameters were significantly associated with seropositivity against IBV in a subsequent multivariable logistic regression analysis. A longitudinal risk factor studies considering management and vaccination characteristics possibly associated with the IBV flock prevalence would be beneficial.