柯萨奇病毒A9型山东地方株的进化遗传学特征

Evolutionary Genetics of Coxsackievirus A9 in Shandong Province,China

柯萨奇病毒A9型(Coxsackievirus A9,CVA9)是常见的人类肠道病毒血清型,其感染可引起无菌性脑膜炎、脑炎等疾病。为探索其进化遗传学特征,本研究对山东省1991-2018年CVA9分离株的VP1完整编码区进行了序列测定,并与GenBank中获得的全球序列一并进行系统发生学和进化遗传学分析。结果显示全球CVA9可分为I-XII 12个基因型,优势基因型为VII,包括山东株在内的所有中国分离株均属于该基因型。进化遗传学研究显示,CVA9 VP1区序列的每年每个碱基的平均进化速率约为6.25×10^(-3),共同祖先起源于1919年。CVA9 VP1区的基因多样性在2003年以前无明显变化,2003年以后出现明显波动。本研究为我们了解CVA9的流行趋势和遗传变异提供了数据,对CVA9相关疾病的防控和诊断试剂的研发具有重要的现实意义。

Coxsackievirus A9(CVA9)is one of the most common serotypes of human enteroviruses. Infection with CVA9 leads to aseptic meningitis,encephalitis,etc. We wished to understand the evolutionary genetics of CVA9. Sequencing of major capsid protein VP1 was done on CVA9 isolates collected in Shandong Province,China,from 1991 to 2018. Their phylogenetic characterization and evolutionary dynamics were analyzed together with global sequences from the GenBank database. We discovered that global CVA9 could be divided into 12 genotypes(I–XII),with VII being predominant. All Chinese isolates(including those from Shandong)belonged to this genotype. The average evolutionary rate of VP1 region of CVA9 was 6.25×10^(-3) substitutions/site/year,and the common ancestor originated in 1919. The genetic diversity of the VP1 region did not vary significantly before 2003,but fluctuated significantly after 2003. Our results aid understanding of the epidemic trend and genetic variation of CVA9. They also have practical importance for the prevention and control of CVA9-related diseases as well as development of diagnostic reagents.