Objective To traceability analysis the first imported dengue fever case reported in Shenzhen city in 2015.
Methods The epidemiology data and serum samples were collected from the cases. Immunochromatography and real-time RT-PCR were used to detect IgM, IgG, NS1 antigen and dengue virus nucleic acid. The samples were inoculated in C6/36 cells for virus isolation. E gene of isolated virus strain was sequenced to construct homology comparison with the standard strains and strains isolated from other areas, and phylogenetic tree was constructed. The sequence of glycosylation sites and virulence sites were compared.
Results IgM, NS1 antigen and RNA of type 2 dengue virus were detected. The dengue virus named DEN2- SZ1503 was successfully isolated. The homology of nucleotide sequence and amino acid sequence of E gene of DEN2-SZ1503 with standard type 2 dengue virus NGC strain were 93.8% and 97.8% respectively. DEN2-SZ1503 and SG(EHI)D2/06572Y13 strain (Malaysia 2013) lied in the same branch of the phylogenetic tree, indicated the greatest similarity between these two strains. DEN2-SZ1503 belonged to genotype IV with 1051 strain (Indonesia 76), 10 strain (Somalia 84) and 271-206 strain (Sri Lanka 90). The sequence of glycosylation sites and virulence sites of SZ1503 were conserved.
Conclusion The first imported dengue fever case reported in Shenzhen city in 2015 was caused by type 2 dengue virus, which consistent with DV popular in Malaysia.
摘要： 目的 对2015年深圳市报告的首例输人性登革热病例进行溯源分析。 方法 收集该病例流行病学资料及 血清样本, 并通过免疫层析法和实时荧光RT-PCR对该病例血清中的特异性IgM抗体、IgG抗体、NS1抗原及病毒核酸 进行检测。用C6/36细胞对血清进行病毒分离。对分离株的E基因进行序列测定, 与不同型别的标准株及不同地区的 分离株进行同源性分析并构建系统发生树。同时对糖基化位点、毒力位点上的序列进行比较。 结果 从该病例血清 中检测出IgM抗体、NS1抗原和2型登革病毒RNA, 并成功从血清样本中分离出登革病毒DEN2-SZ1503。SZ1503与标 准2型登革病毒NGC株E基因的核苷酸及氨基酸序列同源性分别为93.8%和97.8%。系统发生树表明SZ1503与SG (EHI)D2/06572Y13株(Malaysia 2013), 具有最高相似性, 且位于系统发育树的同一分支中。该分离株同1051株(Indonesia 76)、10 株(Somalia 84)和271–206株(Sri Lanka 90)—起属于基因型汉。SZ1503株E基因的糖基化位点与其他 登革热2型毒株相同, 毒力位点也与之前报道的毒株一致。结论病毒学、血清学和流行病学结果表明, 该输人登革热 病例是由2型登革热病毒引起的, SZ1503病毒株的遗传特征与马来西亚流行的登革热病毒一致。