Characterization of a highly pathogenic avian influenza H5N1 virus sublineage in poultry seized at ports of entry into Vietnam.
Highly pathogenic avian influenza H5N1 virus was detected in poultry seized at two ports of entry located in Lang Son Province, Vietnam. Sequence analysis of the hemagglutinin (HA) genes from five H5N1 virus isolates and ten PCR amplicons from chicken cloacal samples revealed their close phylogenetic relationship to clade 7 H5N1 HA genes. However, these HA genes exhibited extensive genetic divergence at both the nucleotide and amino acid levels in comparison to previously described clade 7 viruses; e.g., A/chicken/Shanxi/2/2006. In addition, hemagglutination inhibition tests revealed antigenic differences between these and previously isolated H5N1 viruses from Vietnam. These results indicate that viruses with clade 7 HA are evolving rapidly in poultry in Southeast Asia.
Nguyen
Tung
T
National Centre for Veterinary Diagnostics, Department of Animal Health, Hanoi, Vietnam.
Davis
C Todd
CT
Stembridge
William
W
Shu
Bo
B
Balish
Amanda
A
Inui
Kenjiro
K
Do
Hoa T
HT
Ngo
Huong T
HT
Wan
Xiu-Feng
XF
McCarron
Margaret
M
Lindstrom
Stephen E
SE
Cox
Nancy J
NJ
Nguyen
Cam V
CV
Klimov
Alexander I
AI
Donis
Ruben O
RO