Okamatsu Masatoshi, Saito Takehiko, Yamamoto Yu, Mase Masaji, Tsuduku Satoko, Nakamura Kikuyasu, Tsukamoto Kenji, Yamaguchi Shigeo
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.
Vet Microbiol. 2007 Sep 20;124(1-2):35-46. doi: 10.1016/j.vetmic.2007.04.025. Epub 2007 Apr 19.
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.
2005年5月底，首次从日本的鸡身上分离出H5N2亚型低致病性禽流感（LPAI）病毒。通过主动监测和流行病学监测，发现41个农场的578万只鸡受到感染，并分离出16株H5N2病毒。抗原分析显示这些分离株具有抗原相似性。系统发育分析表明，它们起源于一个共同的祖先，并与自1994年以来在中美洲流行的H5N2毒株聚集在一起。用索引分离株（A/鸡/茨城/1/05）对鸡进行实验感染表明，该病毒在呼吸道中高效复制且无临床症状，经空气传播和/或飞沫传播被认为是一种可能的传播方式。这些结果表明，在日本分离出的H5N2 LPAI病毒对鸡具有高度适应性。
