长沙市2013—2016年HFMD重症病例肠道病毒谱及其基因特征

VP1 gene analysis of CAV 6 and CAV 10 infected severe hand, foot and mouth disease case in Changsha, 2013-2016

目的了解2013年至2016年长沙市手足口重症病例感染柯萨奇病毒A组6型(CAV 6)和柯萨奇病毒A组10型(CAV 10)肠道病毒的流行趋势,并对其VP1基因进化概况进行分析。方法运用描述性统计学分析方法对全市重症手足口病流行病学资料进行整理。CAV 6和CAV 10型肠道病毒阳性咽拭子、肛拭子或粪便标本用逆转录聚合酶链反应(RT-PCR)扩增VP1基因片段,序列比对后用MEGA软件构建进化树。结果 2013—2016年全市共检测111份重症手足口病例标本,肠道病毒阳性标本80份,检出率为72.07%。80份肠道病毒阳性标本中,CAV 6型10株,CAV 10型8株。核苷酸序列的同源性分析发现,CAV 6型肠道病毒核苷酸序列之间存在0.8%~6.6%的差异。CAV 10型肠道病毒核苷酸序列之间存在1.1%~5.6%的变化差异。8株CAV 6型毒株均位于D2分支,1株处于D1分支。6株CAV 10型毒株位于E分支。结论 CAV 6和CAV 10肠道病毒在基因水平并未发生明显突变。重症病例中出现CAV 6型和CAV 10型感染高峰年份,但2016年有所降低,应将CAV 6和CAV 10型肠道病毒纳入常规监测,降低手足口发病风险。

Objective To investigate the molecular characterization and epidemic trend of CAV 6 and CAV 10 subtypein hand, foot and mouth disease severe cases during 2013 and 2016. Methods Epidemiological data was treated withdescriptive statistics methods. Clinical specimens, such as anal and throat swab samples, were identified using real-time PCRafter RNA nucleic acid had been extracted. Then, the VP1 gene segment of CAV 6 and CAV 10 positive samples wereamplified, and sequencing. We used MEGA 6.0 to construct the phylogenetic trees. Results Severe HFMD cases positiveratio was 72.07%, which indicated that 80 cases in 111 samples of enterovirus detection. Then, RT-PCR experiment showedthat all the strains contained three subtypes, including 45 strains of EV 71, 10 strains of CAV 6 and 8 strains of CAV 10. Thehomologous analysis of nucleotide sequence found that there was a difference of 0.8%-6.6% between the nucleotide sequenceof CAV 6. There was a difference of between 1.1% and 5.6% of the nucleotide sequence of CAV 10. Phylogenetic analyzationproved that 8 strains of CAV 6 were belong to D2 branch, one CAV 6 strain belonged to D1 branch. However, 6 strains of CAV10 strains were belong to E branch. Conclusion The genotype of CAV 6 and CAV 10 in severe HFMD cases were tendingtowards stability in Changsha City among 2013 to 2016. The prevalence and genetic evolution of the CAV 6 and CAV 10 viruscould be closely monitored, to prevent a new human pandemics.