• Korean Journal of Veterinary Research
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• v.8 no.1
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• pp.24-30
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• 1968

From 1962 to 1968, serum samples were collected from fowls of six provinces in Korea. The investigator tested for serum neutralizing antibody against the Beaudette strain of intecfious bronchitis virus. Twenty(40 percent)serum samples out of fifty revealed a neutralization index of more than 30. Neuralizing antibodies of infectious bronchitis virus are widely spread among chickens in Korea. Intensive poultry farming zones, adult chickens have been neutralizing antibody of infectious bronchitis virus.

• Korean Journal of Veterinary Research
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• v.9 no.2
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• pp.27-29
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• 1969

Observation of transmissive antibody was made on the rabbit inoculated in the virus of avian infection bronchitis. Throughout the studies, the following experimental results were obtained and summarized here. 1. The antibody of rabbit inoculated with the virus of avian infectious bronchitis were persisted for 2-years. 2. The antibody of adult rabbit against the avian infectious bronchitis virus were transmitted to the suckling rabbit and persisted for 15-weeks.

• Journal of the korean veterinary medical association
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• v.25 no.5
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• pp.282-291
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• 1989

Incidence of infectious bronchitis virus(IBV) infection in vaccinated breeder chickens was investigated by hemagglutination inhibition(HI)test for IBV using Mass 41 antigen. In the breeder chickens with the reduced egg production. chalky deposit. wrinkled

• Korean Journal of Veterinary Service
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• v.25 no.1
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• pp.87-96
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• 2002

In this study, we wanted to determine if the respirotropic JMK strain of infectious bronchitis virus(IBV), which has a spike glycoprotein gene that is 99% similar to the nephropathogenic Gray strain of IBV, could adapt and cause lesions in the kidney following intracloacal passage in chickens. Two day old specific pathogen free(SPF) cchickens were infected with Gray and JMK strains by the intraocular and cloacal route. Several tissue samples were collected at various times. Viruses were recovered from more tissues and earlier in the infection from chickens infected cloacally than chickens infected intraocularly. Virus was isolated from the kidney of chickens infected with Gray by the intraocular route and JMK by the intracloacal route, but not from chicken given JMK the intraocular route. Histopathologically, interstitial nephritis was observed in Gray infected chickens. However, viral RNA or antigen were not detected in the kidney by in situ hybridization and immunohistochemistry. We further passaged the JMK strain ten times in two day old SPF chickens using cloacal inoculation. We examined the virus titer and histopathological change in the kidney at each passage level. The amount of virus recovered from the kidney was stable throughout this serial passage and the passaged virus did not caused renal damage. Further, virus could not be isolated from the kidney when chickens were infected with the passaged virus by the intraocular route. We conclude that the JMK strain has a strict upper respiratory tract tropism since cloacal passage did not produce nephrotropism or nephropathogenicity.

• Korean Journal of Veterinary Service
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• v.25 no.1
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• pp.97-103
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• 2002

Infectious bronchitis(IB) is a viral disease in which continued evolution of the virus is of paramount importance for annual endemics and epidemics in chickens. Since the isolation of IB viruses(IBVs) in the 1930s, over 50 serotypes or variants have been reported worldwide. Continuing evolution is most prominent in the suface glycoproteins of IBV but also occurs in other parts of the genome. This genetic variability results from accumulation of molecular changes that can occur by a number of different mechanisms including genetic drift (point mutations) and genetic shift(RNA recombination). GA98 is a new serotype of IBV identified recently in the United States. In this paper, the evolutionary trend of IBV will be discussed using GA98 serotype as a model.

• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.91-98
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• 2000

Phylogenetic tree constructed from the nucleotide sequences of the S1 gene showed that the 15 Korean strains of infectious bronchitis virus(IBV) examined were classified into 2 genetically distinct groups, except one respiratory strain, RB86, which was clustered with Massachusetts group. All the 5 respiratory strains belonged to Korean group I and the rest 9 nephropathogenic strains belonged to Korean group II according to the analysis, based on S1 gene sequences. Like previous classifications corresponded with the geographic origin, Korean stains were discriminated from geographically distinct reference strains of IBV. The nephropathogenic strains within Korean group IIsharing 96% homology were continuously isolated since 1990, and seemed to be genetically stable. Whereas the respiratory strains within Korean group Ⅰ sharing 88% homology were sporadically isolate since 1986m and seemed to be genetically unstable. Because we found putative accumulated point mutation as well as recombination events in Korean group Ⅰ, we discussed why genetic variations have often occurred in respiratory strains rather than nephropathognic strains.

• Korean Journal of Veterinary Research
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• v.5 no.1
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• pp.43-57
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• 1965

It has been-reported that rabbit serum exhibit an inhibitory action on avian infectious bronchitis virus in embryonating chicken embryo. In this thesis, the biological, serological, physical and chemical properties of normal rabbit serum on the effect of the virus propagation were studied. Throughout the studies, the following experimental results 'were obtained and summarized here. 1. An inhibitory action of rabbit serum on avian infectious bronchitis vrius is due to the normal serum constituents. 2. The nature of the neutralization between normal rabbit serum and the virus is similar to that of the specific antiserum and the virus. 3. Rabbit serum, heat inactivated at $56^{\circ}C$, for 30 minutes, showed its average $log_{10}El,D_{50}Nl$ of 3.7. 4. The inhibitory compound present in the normal rabbit serum is inactivated by means of 5 per cent trypsin, 0.01 M potassium periodate, and absorbed to zymosan. 5. The inhibitory compound was not affected by 0.05 M trichloroacetic acid and 0.005M $KH_2PO_4$. 6. The higher the temperature of heat inactivation of rabbit serum caused the lesser the neutralizing effect on the virus. Heating the serum at $66^{\circ}C$, for 30 minutes brought about a complete loss of the neutralizing index of the serum. 7. No ions, as a cofactor, was incorporated to the inhibitory action of rabbit serum on the virus. 8. The inhibitory compound amays be found in a fraction of serum globulin.

• Korean Journal of Veterinary Service
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• v.14 no.1
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• pp.27-40
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• 1991

In order to investigate the biological properties, pathogenicity and immune responses in artficially infected SPF chickens with Avian infectious bronchitis virus that was isolated from chickens showing IB like signs in southern region of Chung buk. Results obtained throuth the experiments are summarized as follows. 1. From 15 IB suspected cases, two strains of IB virus were isolated, one each from the tracheas and lungs. 2. Infectious bronchitis specific embryo lesions were observed after four serial passages of the isolates in chicken embryos. 3. The field isolates and M-41 strain of IB virus interfered with the replication of Newcastle disease virus in chicken embryos. 4. When specific pathogen free chickens, two week old, were inoculated with the IB virus isolates, clinical respiratory signs as dyspnea, coughing were observed. Airsacculitis was observed by necropsy. 5. AGP antibody positive rates of inoculated SPF chickens were highest on day 14 and lowest on day 36, while HI antibody responses were detected on day 14 in all Groups, the reinoculated Group was shown highest titers. 6. By Indirect immunofluorescence antibody assay of artificially infected SPF chickens, the viral antigens were detected in tissues of larynx, trachea and lung on the 4 th to 7 th days post inoculation.

• Korean Journal of Veterinary Research
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• v.20 no.1
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• pp.59-64
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• 1980

Incidence of avian infectious diseases in breeder chickens was followed serologically. Serum samples were collected during the period of 1978~1979 from breeders throughout country and tested for the presence of antibodies against Salmonella pullorum(SP), Mycoplasma gallisepticum(MG), Avian Infectious Bronchitis virus(AIBV), Infectious Bursal Disease virus(IBDV) and Egg Drop Syndrome Virus(EDS). The tests used serum plate agglutination for SP and MG, immuno-diffusion for AIBV and IBDV and hemagglutination-inhibition test for EDS virus. The results are summarized as follows: 1. Individuals and Hocks incidence rate of Avian Infectious Bronchitis virus were 16.9% and 55.3%. 2. Individuals and Hocks incidence rate of Infectious Bursal Disease virus were 50.1% and 66.4%. 3. Individuals and Hocks incidence rate of sal. pullorum were 17.2% and 65.9%. 4. Individuals and flocks incidence rate of M. gallisepticum were 36.2% and 63.2%. 5. Individuals and flocks incidence rate of Egg Drop Syndrome (BC 14) virus were 14.1% and 46.3%.

• 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.