Abstract
Vietnam is one of the countries most affected by highly pathogenic H5N1 influenza A viruses. To evaluate the potential pathogenicity in mammals of H5N1 viruses isolated from humans in Vietnam, we determined the sequences of all eight genes of 22 human isolates collected between 2003 and 2008 and compared their virulence in mice. The isolates were classified into clade 1 and clade 2.3.4 and differed in pathogenicity for mice. Whilst lysine at position 627 of PB2 (PB2-627K) is a critical virulence determinant for clade 2.3.4 viruses, asparagine at position 701 of PB2 and other unknown virulence determinants appear to be involved in the high pathogenicity of clade 1 viruses, warranting further studies to determine the factors responsible for the high virulence of H5N1 viruses in mammals.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Asparagine / genetics
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Cluster Analysis
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Disease Models, Animal
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Genotype
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Humans
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Influenza A Virus, H5N1 Subtype / isolation & purification*
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Influenza A Virus, H5N1 Subtype / pathogenicity*
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Influenza, Human / virology*
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Lysine / genetics
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Mice
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Mice, Inbred BALB C
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Molecular Sequence Data
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Orthomyxoviridae Infections / pathology
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Orthomyxoviridae Infections / virology
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Phylogeny
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RNA, Viral / genetics
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RNA-Dependent RNA Polymerase / genetics
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Sequence Analysis, DNA
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Sequence Homology
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Vietnam
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Viral Proteins / genetics
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Virulence
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Virulence Factors / genetics
Substances
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PB2 protein, Influenzavirus A
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RNA, Viral
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Viral Proteins
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Virulence Factors
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Asparagine
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RNA-Dependent RNA Polymerase
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Lysine