Genetic characterization and susceptibility on poultry and mammal of H7N6 subtype avian influenza virus isolated in Japan in 2009.
From February to March 2009, six strains of H7N6 subtype avian influenza virus were isolated from quails in three farms in Aichi prefecture in Japan. The isolates were shown to be low pathogenic for chicken by the examination performed using the "Manual of Standards for Diagnostic Tests and Vaccines" by World organisation for Animal Health (OIE). The deduced amino acid sequence at the cleavage site was PE (I/Q/L) PKRR (nucleotide sequences were cct gaa (a/c) (t/a) a cc (a/g) aaa aga aga), suggesting persistence in domestic poultry for some time. The direct putative ancestor strain could not be elucidated by phylogenetic analysis of all genome segments of the quail isolates. Diverged date from a putative common ancestor in a non-rooted phylogenetic tree among quail viruses was estimated between March 2002 and July 2004. Three putative N-linked glycosylation sites resided in the vicinity of the receptor binding pocket of HA1 region. They are considered to decrease the reactivity of neutralizing antibody against the virus. Experiments for the infectivity and pathogenicity of a quail strain to poultry indicated that the quail isolate had higher infectivity to quails than chickens and ducks. Direct and dust-borne and/or droplet-borne transmissions among quail were proven in quails with and without direct contact with experimentally infected quails. The virus is seldom transmitted among chickens either directly or indirectly, and indirect transmission from infected quails to chickens was not observed. The pathogenicity of the quail strain for mammalian, pig and mouse was low, although it could replicate in those animals.
Research Team for Zoonotic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
Yuko
Y
Uchida
Katsushi
K
Kanehira
Masaji
M
Mase
Nobuhiro
N
Takemae
Chiaki
C
Watanabe
Tatsufumi
T
Usui
Yoshikazu
Y
Fujimoto
Toshihiro
T
Ito
Manabu
M
Igarashi
Kimihito
K
Ito
Ayato
A
Takada
Yoshihiro
Y
Sakoda
Masatoshi
M
Okamatsu
Yu
Y
Yamamoto
Kikuyasu
K
Nakamura
Hiroshi
H
Kida
Yasuaki
Y
Hiromoto
Tomoyuki
T
Tsuda
Takehiko
T
Saito
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001717:Birds; D009980:Influenza A virus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000473:pathology / Q000635:transmission* / Q000821:virology*; D007564:Japan; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000635:transmission* / Q000821:virology*; D013997:Time Factors; D014764:Viral Proteins / Q000235:genetics
D000914:Antibodies, Viral; D014764:Viral Proteins