• 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.39 no.6
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• pp.1126-1140
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• 1999

Renal failure is one of the main causes of economic impacts in the poultry industry and complex syndrome with different severity of clinical signs caused by multiple nephropathogenic factors such as infectious bronchitis viral infection and excess salt and calcium in diet. To evaluate the correlation between severity of renal failure and the causative nephropathogenic factors, one-day-old specific pathogen free chicks were treated with either single causative factor or multiple causative factors described as above. Each group was designed as control for non-treated control, IB for infectious bronchitis virus (IB virus) infection, IBHNa for IB virus infection with high diet salt, IBHCa for IB virus infection with high diet calcium, IBHNC for IB virus infection with high diet salt and calcium, HNa for high diet salt, HCa for high diet calcium and HNC for high diet salt and calcium. Chickens were inoculated with IB virus at 1-day-old and remained on their respective diets until 21 day of age. The high dietary salt feeding groups such as IBHNa, IBHNC, HNa, HNC increased water intake, watery diarrhea, general subcutaneous edema and the high dietary calcium feeding groups such as IBHCa and IBHNC showed severe visceral gout. Two more than treated groups caused high mortality in comparison with the single treated groups. IB virus exposure significantly increased urate deposition and lymphocytic interstitial nephritis. Especially urate deposition dramatically increased when excess diet calcium was combined together. In excess diet salt treated groups enlarged edematous kidneys were observed and hypertrophy of glomeruli were showed. These results suggest that IB virus enhanced the incidence and severity on chicken renal failure clearly related to the quantity of salt and calcium.

• Korean Journal of Veterinary Research
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• v.39 no.6
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• pp.1141-1150
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• 1999

Renal failure is one of the main causes of economic impacts in the poultry industry and complex syndrome with different severity of clinical signs caused by multiple nephropathogenic factors such as infectious bronchitis viral infection and excess salt and calcium in diet. To evaluate the correlation between severity of renal failure and the causative nephropathogenic factors, one-day-old specific pathogen free chickens were treated with either single causative factor or multiple causative factors described as above. Each group was designed as control for non-treated control, IB for infectious bronchitis virus (IB virus) infection, IBHNa for IB virus infection with high diet salt, IBHCa for IB virus infection with high diet calcium, IBHNC for IB virus infection with high diet salt and calcium, HNa for high diet salt, HCa for high diet calcium and HNC for high diet salt and calcium. Chickens were inoculated with IB virus at 1-day-old and remained on their respective diets until 21 day of age. Plasma $Na^+$, $Cl^-$, BUN, creatinine, calcium and uric acid values were examined. The results obtained were as follows ; IB virus and high dietary calcium combined treatment showed elevated plasma uric acid. BUN and creatinine values were not characteristic on chicken renal failure. But plasma uric acid values were increased according to renal lesion. Hypercalcemia and hyperuricemia did not induce urate deposition and mineralization in the kidney.

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.193-201
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• 2011

An attenuated vaccine strain AVR1/08 of Korean respiratory type of infectious bronchitis virus (IBV) was developed by 89th passages of IBV D85/06 strain in chicken eggs. The AVR1/08 strain had higher virus titer at least 20 times ($10^{1.3}$) than the parent virus D85/06 by egg inoculation method. The AVR1/08 strain had a single point mutation (S to Y) at position 56 of spike protein of IBV compared to parent virus IBV D85/06 strain. The mutation was observed consistently at viruses after 47th passage in chicken eggs. The AVR1/08 strain showed no virulence even after 6 passages in chickens and all chickens inoculated induced anti-IBV antibody 14 days after vaccination. The AVR1/08 strain had broad protective efficacy against QX type Korean nephropathogenic virus (Q43/06 strain), KM91 type Korean nephropathogenic virus (KM91 strain) and Korean respiratory virus (D85/06 strain). In contrast, Massachusetts (Mass) type attenuated vaccine strain H120 showed protection of 37.5 to 50% against these three viruses. Our results indicate that the AVR1/08 strain has potential as an attenuated vaccine effective in controlling IBVs circulating in Korea.

• 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 Poultry Science
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• v.45 no.1
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• pp.17-28
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• 2018

Infectious bronchitis virus (IBV) is an economically important disease in the poultry industry worldwide. This disease commonly manifests respiratory signs, poor egg quality, and decline in egg production. Since IBV is a RNA virus, the emergence of new variant strains is continuously reported and the immunization of susceptible chickens with only one antigenic type of the virus has been shown to induce partial or no protection against other unrelated types. Therefore, it is difficult to diagnose IBV due to variants serotypes. In this study, we collected serum from various ages of Broiler GP (Grandparent) to Layer CC (Commercial chick) and performed detectability comparison test between domestic company and multinational company manufacturing ELISA kit. Results of this experiment suggest that domestic company manufacturing ELISA kit is more sensitive to infectious bronchitis antibody than that of the multinational company. Our findings also suggest that antibody's change trends after infectious bronchitis vaccination. Thus, the use of appropriate kit for domestic situations is important.