2014年深圳市流行的1型登革病毒分子溯源分析

Molecular phylogenetic analysis of type 1 strains of dengue virus isolated in Shenzhen City during the 2014 dengue outbreak

摘要:

目的  对2014年深圳市登革热（DF）流行时分离的登革热1型病毒株（DENV-1）进行E基因序列测定，了解其分子病毒学特征，探讨其可能来源。方法  收集35份2014年深圳市DF患者急性期血清标本，用乳仓鼠肾细胞（BHK-21）分离DF病毒，并用逆转录-半套式聚合酶链反应（RT-PCR）反应对其进行型别鉴定。RT-PCR扩增全长E基因，测序并进行同源性与进化树分析。结果  35份血清样本中分离到DENV-1 21株。选取6株深圳DENV-1分离株测序，E基因全长1 485 bp，编码495个氨基酸。6株深圳市DENV-1分离株同源性为100.0％，其同源性与深圳市2010流行株接近，核苷酸和氨基酸同源性分别为99.5%和99.8%，与新加坡2009和日本2004流行株的核苷酸和氨基酸同源性最高达99.7%和100.0％。进化分析发现，深圳6株DENV-1属于基因型1型，与Shenzhen2010、Singpore2009、Japan2004的亲缘关系较近，在同一进化支上。结论  2014年深圳市DENV-1属GⅠ亚型，最可能来源于东南亚一带，于2010年本地化而引起2014年DF流行。

Abstract:

Objective To determine the envelope (E) gene sequence of type 1 dengue virus (DENV-1) isolated in Shenzhen in 2014, and to understand the molecular virology characteristics of these strains as well as to explore their possible origin. Methods Thirty-five serum samples were collected from patients with dengue fever. Dengue virus was isolated by BHK-21 cells and the serotypes were detected by semi-nested polymerase chain reaction (PCR). The E gene of the isolated strains was amplified by RT-PCR and sequenced. Homological and phylogenetic trees were also constructed based on the E gene of isolated dengue virus strains. Results Totally 21 strains were isolated from 35 samples and identified as type 1 dengue virus. The complete coding region of E genes from 6 strains of DENV-1 was all composed of 1,485 nucleotides which encoded 495 amino acids. Nucleotide sequence homology of 6 strains of DENV-1 was 100.0％ identical, and their homology was very similar to the epidemic strains of DENV-1 virus in Shenzhen in 2010. The homology of the nucleotide sequence and the deduced amino acid sequence was 99.5% and 99.8％ respectively. Compared with epidemic DENV-1 strains isolated from other countries, DENV-1 from Shenzhen in 2014 was close to the strains isolated in Singpore and Japan, and the highest homology of their E genes and the deduced amino acids was 99.7% and 100.0%. The phylogenetic tree of E genes indicated that the 6 strains of DENV-1 had the greater similarity with Shenzhen2010, Singpore2009 and Japan2004; and they all belonged to the genotype GⅠ. Conclusions DENV-1 strains from Shenzhen in 2014 belonged to thegenotype GⅠ. They most likely originated from Southeast Asian countries. These epidemic dengue virus strains had been settled down in Shenzhen in 2010 and caused 2014 dengue fever outbreak.