Xu Songtao, Zhang Yan, Rivailler Pierre, Wang Huiling, Ji Yixin, Zhen Zhu, Mao Naiying, Li Chongshan, Bellini William J, Xu Wenbo, Rota Paul A
WHO Regional Reference Laboratory for Measles for the Western Pacific Region, National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing 102206, PR China.
Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
J Gen Virol. 2014 Sep;95(Pt 9):1892-1899. doi: 10.1099/vir.0.066746-0. Epub 2014 Jun 9.
Virologic surveillance is a critical component of measles management. One of the criteria for verification of elimination of endemic measles is genetic analysis of wild-type viruses to demonstrate lack of an indigenous genotype. Measles is yet to be eliminated in China, and genotype H1 has been detected continuously since virologic surveillance was initiated in 1993. Virologic surveillance has been very active in China, providing a unique opportunity to conduct a detailed study of the evolution of a single, endemic genotype over a timespan of nearly two decades. Phylogenetic analysis performed on the 450 nt coding sequence for the C-terminal 150 amino acids of the nucleoprotein (N-450), fusion (F) gene and haemagglutinin (H) gene confirmed the continued circulation of genotype H1 viruses for 19 years. No evidence of selective pressure for the H protein was found. The substitution rates ranged from 0.75×10(-3) substitutions site(-1) year(-1) for H to 1.65×10(-3) substitutions site(-1) year(-1) for N-450. The time of most recent common ancestor (TMRCA) for genotype H1 was estimated as approximately 1985 (95 % highest probability density, 1979-1989). Finally, the overall diversity of measles sequences from China decreased from 2005 to 2012, coincident with a substantial decrease in measles cases. The results suggest that detailed evolutionary analyses should facilitate the documentation of eventual measles elimination in China. Moreover, the molecular approaches used in this study can be applied in other countries approaching measles elimination.
病毒学监测是麻疹管理的关键组成部分。验证地方性麻疹消除的标准之一是对野生型病毒进行基因分析，以证明不存在本土基因型。中国尚未消除麻疹，自1993年开始病毒学监测以来，H1基因型一直被持续检测到。中国的病毒学监测非常活跃，提供了一个独特的机会来详细研究单一地方性基因型在近二十年时间跨度内的进化情况。对核蛋白（N - 450）C末端150个氨基酸的450 nt编码序列、融合（F）基因和血凝素（H）基因进行的系统发育分析证实，H1基因型病毒持续传播了19年。未发现对H蛋白有选择压力的证据。替换率范围从H基因的0.75×10⁻³替换位点⁻¹年⁻¹到N - 450基因的1.65×10⁻³替换位点⁻¹年⁻¹。H1基因型的最近共同祖先时间（TMRCA）估计约为1985年（95%最高概率密度，1979 - 1989年）。最后，中国麻疹序列的总体多样性从2005年到2012年有所下降，这与麻疹病例的大幅减少相一致。结果表明，详细的进化分析应有助于记录中国最终消除麻疹的情况。此外，本研究中使用的分子方法可应用于其他接近消除麻疹的国家。
