Grant-in-Aid for Co-operative Research (A).
Applied veterinary science
|Research Institution||Gifu University|
HIRAI Katsuya Gifu Univ., Fact.Agr., Prof., 農学部, 教授 (30021702)
日原 宏 農林水産省, 家畜衛生試験場・研究第2部, 部長
ITAKURA Chitoshi Hokkaido Univ., Fac.Vet., Prof., 獣医学部, 教授 (30021695)
成田 實 農林水産省, 家畜衛生試験場・研究第3部, 室長
YAMAGUCHI Tsuyoshi Gifu Univ., Fac.Agr., Asistant Prof., 農学部, 助手 (70210367)
FUKUSHI Hideto Gifu Univ., Fac.Agr., Associate Prof., 農学部, 助教授 (10156763)
NARITA Minoru Ministry of Agriculture and Forestry, National Institute of Animal Health,
HIHARA Hiroshi Ministry of Agriculture and Forestry, National Institute of Animal Health,
|Project Fiscal Year
1992 – 1994
Completed(Fiscal Year 1994)
|Budget Amount *help
¥10,000,000 (Direct Cost : ¥10,000,000)
Fiscal Year 1994 : ¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 1993 : ¥7,000,000 (Direct Cost : ¥7,000,000)
|Keywords||Infectious bursal disease / Pathogenicity / Prevention / Highly virulent IBDV / 伝染性ファブリキウス嚢病 / 病原性 / 予防対策 / 超強毒IBDV / IBDV|
Pathological analysis showed that highly virulent IBD virus(IBDV)propagate more effectively than classical strains in host chickens. It was also showed that the highly virulent IBDV can propagate in various organs which the classical IBDV may not be able to propagate.
Molecular analysis of highly virulent IBDV
Nucleotide sequences of genomic segments A and B of highly virulent IBDV were determined. The nucleotide sequence of segment A of attenuated strains originating from the highly virulent IBDV were also determined. The nucleotide sequences of segment A and the deduced amino acid sequences of highly virulent strains, attenuated strain and classical strains were compared to define the virulence gene. Phylogenic tree analysis were also carried out to define the origin of highly virulent IBDV.
The attenuated strains showed common nucleotide substitutions in VP2 variable region of segment A.These nucleotide substitutions predicted common amino acid changes. Significant
amino acid differences were also found between highly virulent strains and classical strains in VP2 variable region and precursor protein processed regions. These findings may showed that the amino acid residues at the positions may be a important role to express the high pathogenicities. The nucleotide sequence analysis also showed the existence of highly virulent strains, vaccine strains or classical strains specific restriction sites in the VP2 variable region. These restriction sites are very useful for rapid diagnosis and typing of IBD combined with PCR techique. Phylogenic tree analysis showed that the highly virulent strains appeared before appearance of classical strains.
Establishment of new vaccine against the highly virulent IBD
The highly virulent strains reduced their pathogenicity against young chickens very much after serial passages in embryonated egg and CEF cell. The embryonated egg and CEF cell adapted strains-inoculated chickens did not showed any symptoms. In immunization and protection tests, the attenuated highly virulent strain-immunized chickens were completely protected from the fatal infection of highly virulent IBDV. These findings indicated that the attenuated strains are possibilities to be a new effective live vaccine against highly virulent IBDV infection.
Emargency report of establishment of rapid diagnostic method of highly virulentinfectious bursal disease. Less