The Izumi plain in Kagoshima Prefecture, Japan, is an overwintering site for migratory ducks and endangered cranes. We have surveyed avian influenza viruses (AIVs) in this area since 2012 and isolated low-pathogenic AIVs (LPAIVs) of various subtypes every winter season. H3N8 LPAIVs were isolated during the 2012/13 and 2016/17 seasons, and H4N6 LPAIVs were isolated during the 2012/13 and 2013/14 seasons. In the 2017/18 season, one H3N8 and two H4N6 LPAIV strains were isolated from environmental water samples. Genetic and phylogenetic analysis for each gene segment from these H3N8 and H4N6 LPAIVs suggested that our isolates were genetic reassortants generated by intermixing between AIVs circulating not only in Eurasia but also in Africa and/or North America. Comparison of the genetic constellations of our three isolates with their counterparts isolated during previous seasons from the Izumi plain revealed a drastic transition in the genetic constellations of both subtypes. These findings emphasize the importance of continuous surveillance of AIVs on the Izumi plain.

中文翻译：

---

H3N8和H4N6低致病性禽流感病毒在整个冬季不同季节从日本的越冬地点分离出的遗传星座中的过渡。

日本鹿儿岛县的和泉平原是野鸭和濒危起重机的越冬地点。自2012年以来，我们已经对该地区的禽流感病毒（AIV）进行了调查，并且每个冬季都分离出了各种亚型的低致病性AIV（LPAIV）。H3N8 LPAIV在2012/13和2016/17季节分离，而H4N6 LPAIV在2012/13和2013/14季节分离。在2017/18赛季，从环境水样中分离出了1株H3N8和2株H4N6 LPAIV菌株。对来自这些H3N8和H4N6 LPAIV的每个基因片段的遗传和系统发育分析表明，我们的分离物是不仅在欧亚大陆而且在非洲和/或北美流通的AIV之间相互混合而产生的遗传重配体。比较我们三个分离株的遗传星座与在上一个季节从泉泉平原分离的对应株，发现两种亚型的遗传星座都发生了急剧的转变。这些发现强调了在Izumi平原上持续监视AIV的重要性。