Molecular epizootiology of infectious bursal disease (IBD) in Korea.
We conducted a molecular epizootiological study of infectious bursal disease (IBD) in Korea by analyzing 85 IBD viruses (IBDVs) obtained from vaccinated or unvaccinated flocks between 1980 and 2007. Phylogenetic analysis of the partial nucleotide sequence of the hypervariable region of the VP2 gene (nucleotides 661-1020) and pathogenicity tests revealed more genetic and phenotypic diversity of IBDV in Korea than has been reported previously. We showed that very virulent IBDVs (vvIBDVs) were already present in Korea in 1986. Moreover, vvIBDVs were repeatedly detected in Korean poultry that had been vaccinated, which casts doubt on the IBD vaccine programs. We also identified novel putative antigenic variant (AV)-like IBDV isolates on the basis of their antigenic indices and the presence of amino acid changes (P222S or P222T-A321D) that are known to affect the antigenicity of VP2. These observations suggest that future studies examining the efficacy of conventional vaccines against atrophy of the bursa of Fabricius and vvIBDV shedding may be useful. Moreover, it will be of interest to determine the prevalence of putative Korean antigenic variants and whether these strains exert immunosuppressive effects in vaccinated birds.
Jeon
Woo-Jin
WJ
Avian Disease Division, National Veterinary Research and Quarantine Service, Gyeonggi-Do, Korea.
Choi
Kang-Seuk
KS
Lee
Dong-Woo
DW
Lee
Eun-Kyoung
EK
Cha
Sang-Ho
SH
Cho
Sun-Hee
SH
Kwon
Jun-Hun
JH
Yoon
Yeo-sung
YS
Kim
Sun-Joong
SJ
Kim
Jae-Hong
JH
Kwon
Hyuk-Joon
HJ
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D002645:Chickens; D014644:Genetic Variation; D007243:Infectious bursal disease virus / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D007723:Korea / Q000453:epidemiology; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D011201:Poultry Diseases / Q000453:epidemiology* / Q000821:virology; D012367:RNA, Viral / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015678:Viral Structural Proteins / Q000235:genetics
D000956:Antigens, Viral; D012367:RNA, Viral; D015678:Viral Structural Proteins