• Asian-Australasian Journal of Animal Sciences
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• 제9권4호
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• pp.465-469
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• 1996

Pathological and virological investigations were conducted on suspected outbreaks of infectious bursal disease (IBD) in a broiler farm and five pullet-raising poultry farms of Mymensingh and Tangail districts of Bangladesh. About 80 to 100 percent chicks were affected at the age of 26 to 45 days and mortality varied from 20 to 30 percent in broilers and 40 to 80 percent in layer chicks. Signs, symptoms, gross and microscopic lesions were typical of acute IBD. Several isolates of virus could be obtained by embryo inoculation and the virus was diagnosed as infectious bursal disease virus (IBDV) by agar gel immunodiffusion test (AGID). The virus isolate belonged to the very virulent pathotype of IBDV causing 100 percent mortality in three weeks old chicks on experimental infection.

• 대한수의학회지
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• 제51권1호
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• pp.37-46
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• 2011

Infectious bursal disease virus (IBDV) is a member of the Avibirnavirus genus of the Birnaviridae family which genome consists of two segments (A and B) of double stranded RNA. Segment A gene of KNU08010 isolate, which was isolated from a 15-day-old chicken flock in 2008, was sequenced and compared with other IBDV isolates including SH/92 strain, the first Korean very virulent (vv) IBDV isolate. The amino acid sequences of segment A gene showed that KNU08010 had 99.2% homology with SH92 strain. KNU08010 isolate had specific amino acids A222, I242, I256, I294 and S299 which are highly conserved among vvIBDV strains. Phylogenetic analysis based on the nucleotide sequences of variable region of the VP2 gene of 18 IBDV strains revealed that KNU08010 was grouped with vvIBDVs and was closely related to Korean vvIBDVs isolated from wild birds.

• Journal of Veterinary Science
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• 제22권3호
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• pp.33.1-33.6
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• 2021

Very virulent infectious bursal disease virus (vvIBDV) causes high mortality in chickens but measures to reduce the mortality have not been explored. Chickens (8-9 weeks) were treated with 3 agents before and during vvIBDV inoculation. Dexamethasone treatment reduced the mortality of infected chickens (40.7% vs. 3.7%; p < 0.001), but treatment with aspirin or vitamin E plus selenium did not affect the mortality. The bursa of Fabricius appeared to have shrunk in both dead and surviving chickens (p < 0.01). The results indicate that dexamethasone can reduce mortality in vvIBDV-infected chickens and may provide therapeutic clues for saving individual birds infected by the virus.

• 대한수의학회지
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• 제39권3호
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• pp.545-553
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• 1999

A 474-base pair segment covering the hypervariable region of VP2 gene from six Korean infectious bursal disease virus(K-IBDV) isolates(K1, K2, SH/92, 225, 269, 310) and one attenuated IBDV(DAE) were amplified using RT-PCR, sequenced, and compared with published sequences for IBDV. K-IBDV isolates(K1, K2, SH/92, 225, 269) and foreign very virulent(vv) IBDV strains had 94.93~100% amino acid sequence similarity. K-IBDV isolate 310 and other K-IBDV isolates had 84.31~86.07% amino acid sequence similarity. Attenuated strain(DAE), like other attenuated strain, has substitution at positions 279(D to N) and 284(A to T) as well as in the serine-rich heptapeptide region. Five K-IBDV isolates except 310 isolate share unique amino acid residues at positions 222(A), 256(I), 294(I) which are not present in other standard and attenuated strains. At the two hydrophilic region, K-IBDV isolates except 310 isolate had identical amino acids comparing with Belgium vv IBDV 894VB but had four amino acid substitutions comparing with Chinese vv IBDV F9502. The SWSASGS heptapeptide is conserved in all K-IBDV isolates. The sequence of K-IBDV isolate 310 was markedly different from other IBDV strains, evolving from a separate lineage than the others. By phylogenetic analysis, Five K-IBDV isolates except 310 isolate were categorized in one group with foreign vv IBDV isolates but K-IBDV isolate 310 was categorized in a separate group which was differentiated from other compared IBDV strains.

• 한국동물위생학회지
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• 제35권2호
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• pp.91-97
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• 2012

The strategy for infectious bursal disease (IBD) control and its success rate under field conditions depends on hygiene management, IBD field pressure, level, and variation in maternally derived IBD antibodies. This study investigated the level of IBD-specific antibody by ELISA and the prevalence of IBD virus by PCR in broilers, white-semi broilers, and Korean native chickens raised in Jeongeup, Jeonbuk. IBD-specific maternally derived antibodies were measured from 698 chickens and the mean titers of maternal antibodies were $3,572{\pm}1,402$ in broilers, $1,262{\pm}762$ in white-semi broilers, and $1,932{\pm}912$ in Korean native chickens. At 2 weeks after vaccination, the geometric mean antibody titers of broiler, white-semi broiler, and Korean native chicken were $582{\pm}427$, $3255{\pm}1,080$, and $1,023{\pm}499$, respectively. According to sequence analysis of the variable virion protein 2 gene, 4 isolates were found to be very virulent IBDV, 9 isolates classical virulent, and 2 isolates intermediate plus vaccine strain.

• 한국동물위생학회지
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• 제35권1호
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• pp.9-17
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• 2012

The objective of the present study was to isolate and identify infectious bursal disease viruses (IBDVs) from broiler and layer chickens of outbreaks of infectious bursal disease (IBD) in three districts of Bangladesh. A total of 70 bursal samples were collected from dead broiler (n=40) and layer (n=30) chickens showing specific lesions of IBD from seven commercial poultry farms of three different districts (Mymensingh, Chittagong and Tangail) of Bangladesh during the year 2007. Five representative bursal samples from each farm were used for the isolation of IBDVs using 9-day-old embryonated eggs of seronegative flock of layer birds and for identification the samples were subjected to agar gel immunodiffusion test (AGIDT), immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Out of 35 bursal samples, IBDVs were successfully isolated from 28 (80%) samples. By AGIDT, 32 (91.4%) samples were found positive for IBDV antigen. Results of AGIDT clearly indicated that IBDVs detected in 29 bursal samples of six affected farms were identical to each other but not to IBDVs present in the remaining three samples of another farm. Indirect immunoperoxidase staining of the bursal sections revealed the presence of IBDV antigen in 32 (91.4%) samples and the IBDV antigen was detected mainly in the cortex of the lymphoid follicles of the bursal tissues. In histopathology, cell depletion, atrophy and necrosis were observed in many bursal follicles with severe edema of interfollicular septa. Of the 35 bursal samples, 34 (97.1%) samples generated 254 bp product by RT-PCR. In conclusion, the results of virus isolation and identification by AGIDT, IHC and the analysis of viral genome by RT-PCR confirmed the outbreaks of acute IBD in commercial poultry of Bangladesh. Moreover, histopathological findings and results of AGIDT gave a clear indication that the isolates from six outbreaks were different from classical strain and it seems to be of very virulent strain. On the other hand, the isolates from the other outbreak were similar to the classical strain.

• 대한수의학회지
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• 제43권3호
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• pp.439-448
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• 2003

The VP2 gene of infectious bursal disease virus (IBDV) Chinju which was previously detected in Chinju, Korea was cloned and sequenced to establish the information for the development of genetically engineered vaccines and diagnostic reagents against IBDV. The nucleotide sequence of the entire Chinju VP2 gene consisted of 1,356 bases long encoding 452 amino acids in a single open reading frame (ORF). It consisted of 368 adenine (27.1%), 363 cytosine (26.8%), 339 guanine (25.0%) and 286 thymine (21.1%) residues. The predicted $M_r$ of the Chinju VP2 protein was 48 kDa, and the protein contained 13 phosphorylation sites by protein kinase C, casein kinase II or tyrosine kinase, whereas 3 asparagine-linked glycosylation sites were recognized. The nucleotide sequence of Chinju VP2 ORF had a very close phylogenetic relationship with 98-99% homology to that of the very virulent IBDVs (vvIBDVs) HK46, OKYM, D6948, UK661, UPM97/61 and BD3/99. Also, the Chinju VP2 protein revealed a very close phylogenetic relationship with 99-100% homology to that of these vvIBDVs. The Chinju VP2 protein had 100% amino acid identity in the variable region of residues 206-360 with that of the D6948, HK46, OKYM and UK661, as well as 100% identity in two hypervariable regions of residues 212-224 and 314-324 with those of the D6948, HK46, OKYM, UK661, UPM97/61 and BD3/99. The amino acid sequence of the chinju VP2 protein contained a serine-rich heptapeptide of SWSASGS as in these vvIBDVs.

• 한국가금학회지
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• 제37권2호
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• pp.167-172
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• 2010

닭 전염성 F낭병 (IBD)은 닭에서 전염성이 강하고 발병으로 인하여 양계 산업에 막대한 경제적 피해를 입히는 닭의 바이러스성 전염병이다. 이 연구에서는 수 분 이내에 검사 시료로부터 닭 전염성 F낭병 바이러스를 검출할 수 있는 시판용 면역크로마토그래피법 검사 킷트를 이용하여 IBD 진단에 있어서의 유용성을 조사하였다. 사용한 면역크로마토그래피법 검사 킷트는 닭 전염성 F낭병 바이러스 VP2에 특이적인 단클론 항체를 이용하여 닭 전염성 F낭병 바이러스를 검출하도록 고안되었다. 바이러스 감염 역가를 알고 있는 IBDV를 사용하여 조사한 결과, IC 검사 킷트의 검출 한계는 $10^{3.1}$ 내지 $10^{3.9}$ $EID_{50}$/mL이었다. 이 검사 킷트는 닭의 다른 전염성 바이러스인 뉴캣슬병 바이러스, 닭 전염성 기관지염 바이러스, 조류인플루엔자 바이러스 및 전염성 후두기관염 바이러스에 대하여 비특이 반응을 나타내지 않았다. 고병원성의 IBDV를 실험적으로 감염시킨 후 3일 내지 4일에 폐사한 닭의 장기별로 조사한 결과, 모든 폐사 닭의 F낭, 장편도, 비장, 신장 시료들은 면역크로마토그래피법 검사 킷트에서 강한 양성반응을 나타내었다. 검사 시료 중 F낭 시료가 IC 검사 킷트에서 가장 강한 양성반응을 나타내었다. 폐사 닭의 간, 흉선, 선위의 경우, 각각 검사시료의 87.5%, 37.5% and 0%가 양성 반응을 나타내었다. 면역크로마토그래피법 검사 킷트에서 음성이었던 시료 중 흉선 시료 한 점을 제외한 모든 시료는 DAS-ELISA와 동일한 검사 결과를 나타내었으나, 검사 시료 중 흉선과 선위 일부에서 RT-PCR 검사에서 양성 반응을 나타내었다. 야외 IBD 발생 농장과 비발생 농장에서 수거한 폐사닭 231수의 조직을 면봉으로 도말하여 채취한 시료를 조사하여 RT-PCR법과 비교한 결과, 상대적 민감도와 특이도는 각각 100% (109/109) 및 97.5% (119/122)를 나타났으며, 두 검사 방법간 kappa value는 0.97이었다. 우리의 연구 결과는 IC 검사 킷트는 야외 양계 농장에서 폐사 닭을 대상으로 IBD를 진단하는 데 적용하기에 매우 유용하다는 것을 말해준다.

• 미생물학회지
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• 제45권2호
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• pp.91-98
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• 2009

닭의 전염성 F낭병 바이러스(IBDV)가 원인 바이러스인 전염성 F낭병은 전 세계 양계산업에 경제적으로 피해가 큰 중요한 질병이다. 이 연구의 목적은 닭에서 IBDV에 대한 방어면역을 유도하기 위한 in ovo 초회항원자극(priming)과 불활화백신에 의한 보강접종 방법에 항원보강제(adjuvant)로 chicken interleukin 6 (pcDNA-ChIL-6;plasmid encoding chicken interleukin-6)와 levamisole (LMS)의 효과를 조사하는 것이다. IBDV의 VP2, VP, VP3 protein을 암호화하는 유전자백신인 plasmid DNA vaccine (pcDNA-VP243) 단독 또는 pcDNA-ChIL-6 또는 LMS와 함께 18일령 부화란의 양막낭(amniotic sac)에 접종하고 부화한 1주령의 병아리에 불활화 IBD 백신을 근육 접종한 다음 3주령에 고병원성 IBDV인 SH/92 주로 공격 접종하고 10일 동안 관찰하였다. 백신하지 않은 공격접종 대조군이 100%의 폐사율을 보인 반면 pcDNA-VP243 단독 접종군과 pcDNA-VP243에 pcDNA-ChIL-6 또는 LMS를 첨가한 실험군은 모두 100%의 생존율을 나타내었다. 그러나 공격접종 후 F낭의 손상을 평가하기 위한 IBDV RNA의 검출, B/B ratio와 F낭의 병변지수(lesion score) 등을 분석한 결과 pcDNA-VP243에 pcDNA-ChIL-6 또는 LMS를 첨가한 실험군은 pcDNA-VP243 단독 접종군보다 향상된 방어효과를 나타내지 않았다. 이 실험결과는 유전자백신에 의한 in ovo 초회항원자극-불활화백신에 의한 보강접종법이 고병원성 IBDV로부터 닭을 보호하기 위한 효과적인 방법이었으나 pcDNA-ChIL-6 또는 LMS의 첨가로 인한 방어효과의 향상은 나타나지 않았다.