Objective To investigate the molecular epidemiology and genetic diversity of rubella virus isolates collected from 2014 to 2019 in Changsha city.
Methods Throat swab samples of suspicious rubella case were detected by real time-PCR. The E1 gene fragment of rubella positive samples was amplified by reverse transcription polymerase chain reaction (RT- PCR). Sequences were analyzed by sequence alignment and phylogenetic tree construction using DNASTAR Lasergene and MEGA 6.0 software.
Results Up to October 31, 2019, 1 726 suspicious rubella cases were collected from Changsha city. The rubella positive rate was 5.04%(87/1726). The prevalence from 2014 to 2019 was 1.27%(6/471), 1.70%(4/235), 1.83%(4/218), 0%(0 / 133), 11.18%(18 / 161) and 10.83%(55 / 508), respectively. We observed the positive rate of rubella virus increased significantly in 2018 year. 62.07% (54 / 87) of infected cases were occurred between 10 and 20 years old. In our research, we obtained 31 sequences of rubella virus, including 3 strains of 2B in 2014, 1 strain of 1E and 1 strain of 2B in 2016, 10 strains of 1E in 2018 and 16 strains of 1E in 2019. GenBank accession number were MN251800-MN251830. Phylogenetic tree analysis showed that rubella isolates from 2018 to 2019 were located with strains from Hongkong in the same branch, distinguish from the prevalence strains that had been isolated in Changsha city previously. The nucleotide homology analysis showed that the sequences have 99.5%-100.0% similarity with each other, and also have 96.0%-96.4% similarity with WHO reference strains. The key nucleotide acid sites in E1 gene did not change, except 324 (A to T) and 329 (F to L) sites.
Conclusion The major causal agents of rubella infection and outbreaks in 2018-2019 year may came from other district not the local strains. The genotype of rubella virus is still remain. We should strengthen the local students and adult′ s rubella vaccination program and rubella virologic surveillance.
摘要: 目的 对 2014—2019 年长沙市风疹病毒进行分子流行病学、基因特征及溯源研究。 方法 风疹疑似患者鼻 咽拭子先通过荧光逆转录聚合酶链反应 (real time-PCR, RT-PCR) 进行风疹病毒核酸检测, 风疹病毒阳性标本再进行 RT-PCR 扩增 E1 基因片段, 序列拼接后构建进化树及氨基酸同源性分析。 结果 截至 2019 年 10 月 31 日, 收集到市区 上送风疹疑似病例标本 1 726 份, 其中阳性 87 份 (5.04%) , 2014 年至 2019 年风疹阳性率分别为 1.27% (6/471)、1.70% (4/ 235)、1.83% (4/218)、0% (0/133)、11.18% (18/161) 和 10.83% (55/508) 。2018 年开始风疹病例显著增多。感染人群中 62.07% (54/87) 分布于 10~20 岁。本研究共获得 31 株风疹病毒序列, 2014 年 3 株 2B 型, 1 株 1E 型; 2016 年 1 株 2B 型; 2018 年 10 株 1E 型; 2019 年 16 株 1E 型。GenBank 序列号为 MN251800-MN251830。进化树分析显示 2018—2019 年毒 株与香港地区本土循环流行的 1E 基因型毒株位于同一分支, 区别于 2018 年以前长沙市地区流行的毒株。毒株之间的 核苷酸同源性为 99.5%~100.0%, 与 WHO 参考株核苷酸同源性为 96.0%~96.4%。E1 基因第 324 位 A 突变为 T, 第 329 位 F 突变为 L, 关键位点未发生变化。 结论 2018—2019 年长沙地区风疹流行毒株为不同地区同一 1E 基因型毒株感染造 成, 应加强本地学生及成年人中风疹疫苗接种计划及风疹病毒学的监测。