title: Recent H5N1 avian influenza A virus increases rapidly in virulence to mice after a single passage in mice.
abstract: To evaluate the potential pathogenicity to mammals of the recent H5N1 avian influenza A virus, viruses recovered from dead mice infected with A/chicken/Yamaguchi/7/2004 isolated in Japan were examined. All recovered viruses from the brains of dead mice infected with this strain (without any prior adaptation to mice) had substituted the amino acid at position 627 of the PB2 protein from glutamic acid to lysine. Their mouse lethality had increased by approximately 5 x 10(4) times over that of the original virus. Histopathological analysis reinforced the finding that these variants caused more rapid and severe damage to mice than the original virus. This revealed that it might be useful to characterize the recovered virus to assess its potential pathogenicity to mammals.
authors.affiliation: Department of Infectious Diseases, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Masaji
authors.initials: M
authors.lastname: Mase
authors.affiliation: Department of Infectious Diseases, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Tanimura
authors.affiliation: Department of Infectious Diseases, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Imada
authors.affiliation: Department of Infectious Diseases, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Okamatsu
authors.affiliation: Department of Infectious Diseases, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Tsukamoto
authors.affiliation: Department of Infectious Diseases, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yamaguchi
mesh_terms: D000220:Adaptation, Biological; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D001921:Brain / Q000821:virology; D002645:Chickens / Q000821:virology; D018698:Glutamic Acid / Q000235:genetics; D006651:Histocytochemistry; D007150:Immunohistochemistry; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000821:virology; D008239:Lysine / Q000235:genetics; D051379:Mice; D020125:Mutation, Missense; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000821:virology*; D012367:RNA, Viral / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics*; D014774:Virulence
chemical_list: C502893:PB2 protein, influenza virus; D012367:RNA, Viral; D014764:Viral Proteins; D018698:Glutamic Acid; D008239:Lysine