• 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.

• 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.

• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.203-206
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• 1998

Two-day-old commercial chicks were inoculated orally with 2 × 106 oocysts of Cwptosporinium bailevi and vaccinated with 103.5 EID50/head of a commercially available avian infectious bronchitis (IB) live virus vaccine at 4 and 14 days following inoculation. Chicks infected with C. baileyi were shown to have an immunosuppressive effect on IB virus. It is concluded that infection with the protozoon in early life may increase their susceptibility to IB.

• Korean Journal of Poultry Science
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• v.19 no.3
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• pp.137-150
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• 1992

Poultry production in korea is a very complex situation. Large modernized farms and old styles of small farming coexist with one another. This gives rise to a tangled epidemiological situation in terms of infectious diseases. The main poultry diseases of economic importance are colibacillosis, pullorum diseases, Mycoplasma gallisepticum infection, infectious coryza, infectious synovitis, Newcasyle disease, fowl pox, Marek's disease, avian encephalomyelitis, infectious bursal disease, infectious laryngotracheitis, infectious bronchitis and coccidiosis. Avian influenza, fowl cholera and fowl typhoid have not been reported for a few decades, and these are rated as exotic diseases.

• Journal of Veterinary Clinics
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• v.24 no.4
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• pp.603-607
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• 2007

The sample sizes required to detect at least one chicken infectious bronchitis virus(IBV) infection at flock-level were determined using pooled samples for 48 submissions with different samples in each. A total of serum samples of 9,980 layers from Kangwon, Chungpook and Chungnam province were collected and tested hemagglutination inhibition(HI) antibody titers against IBV both individually and with pooling size of 10. Of the 48 submissions, 72.9% were required less than 5 pools to detect at least one infected pool at 95% confidence level, and the corresponding rate was 77.1% at 90% confidence level. Overall, the number of pools was decreased as the percent of positive pools increased. At two different cut-of HI titer${\geq}9\;and{\geq}10$ for individual samples the seroprevalence was 50.1% and 33.4%, respectively while 59.9% were seropositive for pooled samples at HI $titer{\geq}8$. The correlation coefficients between pooled and individual samples at each submission were 0.592(p<0.001) for HI $titer{\geq}9$ and 0.561(p<0.001) for ${\geq}10$, with common correlation coefficient of 0.576. This study indicated that pooled testing for the detection of IBV infection may be an alternative strategy when only the pooled results are of interest and the prevalence has not known exactly.

• Journal of Veterinary Clinics
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• v.23 no.4
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• pp.416-420
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• 2006

Compare to testing sera individually, pooled-serum testing has considered as a cost-effective method, particularly on a large population-based seroprevalence studies. This study was to determine the relationship between individual sera and pooled sera titers for detection of avian infectious bronchitis virus (IBV) and to evaluate suitability of pooled sera by comparing prevalences estimated from both samples. A total of 5,000 individual samples were collected from 500 flocks in Chungcheong, Gyunsgi, and Kangwon provinces between January 2005 and February 2006. Ten samples were randomly selected from each flock. Five-hundred pooled sera were prepared by mixing equal amount of each 10 individual serum from the original samples. IBV antibody titers were measured by hemagglutination inhibition (HI) test. The least squares regression analysis was performed to construct equation between pooled and mean individual titers. To determine whether the flock is infected 4 arbitrary criteria were used: detection of at least 1 chicken with HI titer ${\ge}$ 9 (criterion 1), detection of at least 2 samples with HI titer ${\ge}$9 (criterion 2), detection of at least 1 sample with HI titer ${\ge}$ 10 (criterion 3), and filially detection of at least 1 sample with HI titer ${\ge}$ 11 (criterion 4). The receiver operating characteristic (ROC) curve was used to examine the cut-off points of pooled titers showing optimal diagnostic accuracy. The area under the curve (AUC), sensitivities (Se), specificities (Sp), and positive (PPV) and negative (NPV) predictive values were calculated. The regression equation between pooled titers (pool) and mean individual titers (mean) was: $pool= 1.2498+0.8952{\times}mean$, with coefficient of determination of 87% (p< 0.0001). The optimal cut-off points of pooled titers were titer 8 for criterion 1 (AUC=0.975, Se=0.883, Sp=0.959, PPV=0.985, NPV=0.728), titer 8 for criterion 2 (AUC=0.969, Se=0.954, Sp=0.855, PPV=0.926, NPV=0.907), titer 9 for criterion 3 (AUC=0.970, Se=0.836, Sp=0.967, PPV=0.978, NPV=0.772), and titer 9 for criterion 4 (AUC= 0.946, Se=0.928, Sp=0.843, PPV=0.857, NPV=0.921). The difference of 'prevalence estimated by individual and pooled sample showed a minimum of 2% for criteria 2 and a maximum of 9.1:% for criteria 3. These results indicate that the use of pooled sera in HI test for screening IBV infection in laying hen flocks is considered as a cost-effective method of testing large numbers of samples with high diagnostic accuracy.

• 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.

• Journal of Veterinary Science
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• v.24 no.4
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• pp.51.1-51.17
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• 2023

Background: To date, various genotypes of infectious bronchitis virus (IBV) have co-circulated and in Korea, GI-15 and GI-19 lineages were prevailing. The spike protein, particularly S1 subunit, is responsible for receptor binding, contains hypervariable regions and is also responsible for the emerging of novel variants. Objective: This study aims to investigate the putative major amino acid substitutions for the variants in GI-19. Methods: The S1 sequence data of IBV isolated from 1986 to 2021 in Korea (n = 188) were analyzed. Sequence alignments were carried out using Multiple alignment using Fast Fourier Transform of Geneious prime. The phylogenetic tree was generated using MEGA-11 (ver. 11.0.10) and Bayesian analysis was performed by BEAST v1.10.4. Selective pressure was analyzed via online server Datamonkey. Highlights and visualization of putative critical amino acid were conducted by using PyMol software (version 2.3). Results: Most (93.5%) belonged to the GI-19 lineage in Korea, and the GI-19 lineage was further divided into seven subgroups: KM91-like (Clade A and B), K40/09-like, QX-like (I-IV). Positive selection was identified at nine and six residues in S1 for KM91-like and QX-like IBVs, respectively. In addition, several positive selection sites of S1-NTD were indicated to have mutations at common locations even when new clades were generated. They were all located on the lateral surface of the quaternary structure of the S1 subunits in close proximity to the receptor-binding motif (RBM), putative RBM motif and neutralizing antigenic sites in S1. Conclusions: Our results suggest RBM surrounding sites in the S1 subunit of IBV are highly susceptible to mutation by selective pressure during evolution.

• 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.

• Clinical and Experimental Pediatrics
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• v.64 no.11
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• pp.543-551
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• 2021

The human microbiome, which consists of a collective cluster of commensal, symbiotic, and pathogenic microorganisms living in the human body, plays a key role in host health and immunity. The human nasal cavity harbors commensal bacteria that suppress the colonization of opportunistic pathogens. However, dysbiosis of the nasal microbial community is associated with many diseases, such as acute respiratory infections including otitis media, sinusitis and bronchitis and allergic respiratory diseases including asthma. The nasopharyngeal acquisition of pneumococcus, which exists as a pathobiont in the nasal cavity, is the initial step in virtually all pneumococcal diseases. Although the factors influencing nasal colonization and elimination are not fully understood, the adhesion of opportunistic pathogens to nasopharyngeal mucosa receptors and the eliciting of immune responses in the host are implicated in addition to bacterial microbiota properties and colonization resistance dynamics. Probiotics or synbiotic interventions may show promising and effective roles in the adjunctive treatment of dysbiosis; however, more studies are needed to characterize how these interventions can be applied in clinical practice in the future.