Low pathogenicity H5N2 avian influenza outbreak in Japan during the 2005-2006.
At the end of May 2005, a low-pathogenicity avian influenza (LPAI) virus of subtype H5N2 was isolated for the first time from chickens in Japan. Through active and epidemiological surveillance, 5.78 million chickens on 41 farms were found to be affected and 16 H5N2 viruses were isolated. Antigenic analysis revealed antigenic similarity of these isolates. Phylogenetic analysis showed that they originated from a common ancestor and clustered with the H5N2 strains prevalent in Central America that have been circulating since 1994. Experimental infection of chickens with the index isolate (A/chicken/Ibaraki/1/05) demonstrated that this virus replicated efficiently in the respiratory tract without clinical signs, and dust-borne and/or droplet-borne transmission was considered as a possible mode of transmission. These results suggested that the H5N2 LPAI viruses isolated in Japan were highly adapted to chickens.
Okamatsu
Masatoshi
M
Research Team for Zoonotic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
Saito
Takehiko
T
Yamamoto
Yu
Y
Mase
Masaji
M
Tsuduku
Satoko
S
Nakamura
Kikuyasu
K
Tsukamoto
Kenji
K
Yamaguchi
Shigeo
S
D000818:Animals; D000940:Antigenic Variation; D001483:Base Sequence; D002478:Cells, Cultured; D002645:Chickens; D016000:Cluster Analysis; D004196:Disease Outbreaks / Q000662:veterinary; D053125:Influenza A Virus, H5N2 Subtype / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D007564:Japan / Q000453:epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D012367:RNA, Viral / Q000737:chemistry; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D013696:Temperature; D014779:Virus Replication
D012367:RNA, Viral