Tanikawa Taichiro, Kanehira Katsushi, Tsunekuni Ryota, Uchida Yuko, Takemae Nobuhiro, Saito Takehiko
Influenza and Prion Disease Research Center, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856.
United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu City 501-1193, Japan.
Microbiol Immunol. 2016 Apr;60(4):243-52. doi: 10.1111/1348-0421.12369.
Poultry outbreaks caused by H5N8 highly pathogenic avian influenza viruses (HPAIVs) occurred in Japan between December 2014 and January 2015. During the same period; H5N8 HPAIVs were isolated from wild birds and the environment in Japan. The hemagglutinin (HA) genes of these isolates were found to belong to clade 2.3.4.4 and three sub-groups were distinguishable within this clade. All of the Japanese isolates from poultry outbreaks belonged to the same sub-group; whereas wild bird isolates belonged to the other sub-groups. To examine whether the difference in pathogenicity to chickens between isolates of different HA sub-groups of clade 2.3.4.4 could explain why the Japanese poultry outbreaks were only caused by a particular sub-group; pathogenicities of A/chicken/Miyazaki/7/2014 (Miyazaki2014; sub-group C) and A/duck/Chiba/26-372-48/2014 (Chiba2014; sub-group A) to chickens were compared and it was found that the lethality of Miyazaki2014 in chickens was lower than that of Chiba2014; according to the 50% chicken lethal dose. This indicated that differences in pathogenicity may not explain why the Japanese poultry outbreaks only involved group C isolates.
2014年12月至2015年1月期间，日本发生了由H5N8高致病性禽流感病毒（HPAIVs）引起的家禽疫情。同一时期，在日本从野生鸟类和环境中分离出了H5N8 HPAIVs。这些分离株的血凝素（HA）基因属于2.3.4.4分支，在该分支内可区分出三个亚组。所有来自家禽疫情的日本分离株都属于同一亚组；而野生鸟类分离株则属于其他亚组。为了研究2.3.4.4分支不同HA亚组的分离株对鸡的致病性差异是否可以解释为什么日本的家禽疫情仅由一个特定亚组引起，对A/鸡/宫崎/7/2014（宫崎2014；C亚组）和A/鸭/千叶/26 - 372 - 48/2014（千叶2014；A亚组）对鸡的致病性进行了比较，发现根据50%鸡致死剂量，宫崎2014对鸡的致死率低于千叶2014。这表明致病性差异可能无法解释为什么日本的家禽疫情仅涉及C组分离株。
