Ruenphet Sakchai, Jahangir Alam, Shoham Dany, Morikawa Kae, Miyoshi Yuki, Hanawa Eiko, Okamura Masashi, Nakamura Masayuki, Takehara Kazuaki
Laboratory of Zoonoses, School of Veterinary Medicine, Kitasato University, Toada, Aomori, Japan.
Avian Dis. 2011 Jun;55(2):230-5. doi: 10.1637/9589-102510-Reg.1.
A total of 38 Newcastle disease virus (NDV) isolates were obtained from 6060 fecal samples from northern pintail (Anas acuta) ducks collected in the Tohoku district in Japan during 2006-09. One isolate from each sampling location and date was selected for a total of 38 isolates, then 15 of these were characterized for their pathogenicity by mean death time of minimum lethal dose (MDT/MLD) using chicken embryos and by plaque formation on chicken embryo fibroblasts. Furthermore, nine isolates were randomly selected from these 15 isolates, and the fusion protein genes were sequenced to characterize amino acid sequences around the cleavage site. All 15 were confirmed to be nonvirulent by MDT/MLD test, and nine isolates were also confirmed as nonvirulent by the cleavage site of the fusion protein 112G/E-K/R-Q-G/E-R*L117 that was specific for nonvirulent NDVs. The characteristics of nine isolates identified by phylogenic analysis of the fusion protein gene indicated that the isolates belong to genotype I or II. In addition, we also isolated 68 avian influenza viruses and 28 other hemagglutinating viruses. Our data indicate that northern pintails are subclinically infected by, perpetuate, and distribute NDV along with different subtypes of avian influenza viruses and other hemagglutinating viruses during their migrations across vast areas over the Northern Hemisphere to Japan.
2006年至2009年期间，在日本东北地区采集了6060份针尾鸭（Anas acuta）粪便样本，从中共获得38株新城疫病毒（NDV）分离株。从每个采样地点和日期选取一株分离株，共38株，然后通过鸡胚最小致死剂量平均死亡时间（MDT/MLD）以及在鸡胚成纤维细胞上形成蚀斑来对其中15株进行致病性鉴定。此外，从这15株中随机选取9株，对融合蛋白基因进行测序，以鉴定裂解位点周围的氨基酸序列。通过MDT/MLD试验确认所有15株均无致病性，通过融合蛋白112G/E-K/R-Q-G/E-R*L117的裂解位点（这是无毒力NDV的特异性位点）也确认9株无致病性。通过对融合蛋白基因进行系统发育分析确定的9株分离株的特征表明，这些分离株属于I型或II型。此外，我们还分离出68株禽流感病毒和28株其他血凝病毒。我们的数据表明，针尾鸭在其跨越北半球广大地区迁徙至日本的过程中，会受到NDV的亚临床感染，并使其持续存在和传播，同时还伴有不同亚型的禽流感病毒和其他血凝病毒。
