Department of Virology, School of Public Health, Shandong University, Jinan 250012, China.
Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan 250012, China.
Infect Genet Evol. 2019 Nov;75:103958. doi: 10.1016/j.meegid.2019.103958. Epub 2019 Jul 9.
The avian infectious disease, Newcastle disease (ND), caused by Newcastle disease virus (NDV) can cause severe economic losses to poultry whether vaccinated or not in many countries. In this study, a strain of NDV isolated from an outbreak in China was subjected to biological, phylogenetic and genetic characterization. The results showed that the mean death time (MDT) was 52.4 h and the intracerebral pathogenicity indices (ICPI) value was 1.95. In addition, amino acid sequencing result showed that it had a sequence R-R-Q-R-RF at fusion protein cleaving site (FPCS) indicating a velogenic strain. And its genome length is 15,192 nucleotide (nt) with the conserved complementary 3' leader and 5' trailer regions encoding six genes, 3'-NP-P-M-F-HN-L-5'. Based on phylogenetic analyses for hyper-variable region and complete genome of F gene, the strain studied here can be clustered into genotype IX, Class II, which has little evolution distance with strains of genotype III, being considered as a transitional strain in the evolution history of NDV. The rescue of infectious cDNA is proceeded in 9-day-old embryonated SPF chicken eggs. Despite the death of the first generation, the allantoic fluid harvested from the first generation lost its pathogenicity after passage. And we found the phenomenon happened due to the antibody appearing in the allantoic fluid. These findings offer our understanding of circulating strains of NDV in China and lay scientific foundations for making more efficient vaccines for Newcastle disease.
新城疫（ND）是一种由新城疫病毒（NDV）引起的禽类传染病，无论接种疫苗与否，在许多国家都会给家禽业造成严重的经济损失。本研究对一株从中国暴发疫情中分离得到的 NDV 毒株进行了生物学、系统进化和遗传特征分析。结果表明，该分离株的平均死亡时间（MDT）为 52.4 小时，脑内致病指数（ICPI）值为 1.95。此外，氨基酸测序结果显示，其融合蛋白裂解位点（FPCS）处具有 R-R-Q-R-RF 序列，表明该分离株为强毒力株。其基因组全长为 15192 个核苷酸（nt），具有保守的互补 3' 先导区和 5' 尾随区，编码六个基因，3'-NP-P-M-F-HN-L-5'。基于 F 基因高变区和全基因组的系统进化分析，本研究中分离的毒株可归为基因型 IX、Ⅱ类，与基因型 III 毒株进化距离较小，被认为是 NDV 进化史上的过渡株。在 9 日龄 SPF 鸡胚中进行了感染性 cDNA 的拯救。尽管第一代鸡胚死亡，但第一代收获的鸡胚尿囊液在传代后失去了致病性。我们发现这种现象是由于鸡胚尿囊液中出现了抗体。这些发现加深了我们对中国流行 NDV 株的认识，为研制更有效的新城疫疫苗奠定了科学基础。
