Department of Statistics, Faculty of Commerce and Accountancy, Chulalongkorn University, 254 Phyathai Road, Pathumwan, Bangkok 10330, Thailand.
Evolutionary Genetics and Computer Biology Research Unit, Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao District, Chatuchak, Bangkok 10900, Thailand.
Virus Res. 2020 Sep;286:198041. doi: 10.1016/j.virusres.2020.198041. Epub 2020 Jun 1.
Dengue diseases are a group of infectious diseases that have been widespread throughout the world for several decades. Dengue outbreaks have occurred in many parts of the world, including Southeast Asia. The outbreak and the severity of the diseases depend on many factors including dengue genotype. Data on the genetic variation of dengue virus is highly informative for dengue protection plans and vaccine development. In this study, we focused on the analyses of genetic variation and amino acid changes of the whole coding sequences in two dengue strains isolated from Aedes mosquitoes in Bangkok, Thailand, an endemic area. The strains were identified as belonging to dengue virus serotype 1 (DENV-1) genotype I, and have unique nucleotide sequences. In the recombinant analysis, these strains were identified as recombinants derived from Chinese counterparts for both the major (DENV-1 genotype I) and the minor (DENV-1 genotype IV) parental strains. The recombination event occurred within the prM and E genes. This corresponded with the result of multiple alignments where several amino acid residues between the recombination breakpoints in the strains were identical to those in DENV-1 genotype IV. Several of the amino acid substitutions also have changed the amino acid properties, which might affect viral infection and antigenicity. These results provide insight into the genetic variation of DENV in this endemic area, which might have been involved in the dengue outbreak and high numbers of dengue haemorrhagic fever and dengue shock syndrome cases in Thailand in 2015.
登革热疾病是一组传染病，几十年来在全球范围内广泛传播。登革热疫情在世界许多地区包括东南亚都有发生。疫情的爆发和疾病的严重程度取决于许多因素，包括登革热基因型。登革热病毒遗传变异的数据对于登革热防控计划和疫苗开发非常有意义。在这项研究中，我们专注于分析从泰国曼谷伊蚊中分离的两种登革热病毒株的全编码序列的遗传变异和氨基酸变化，该地区为登革热流行区。这两种病毒株被鉴定为属于登革热病毒血清型 1（DENV-1）基因型 I，具有独特的核苷酸序列。在重组分析中，这些病毒株被鉴定为源自中国的主要（DENV-1 基因型 I）和次要（DENV-1 基因型 IV）亲代病毒株的重组体。重组事件发生在 prM 和 E 基因内。这与多个序列比对的结果一致，在这些病毒株的重组断点之间有几个氨基酸残基与 DENV-1 基因型 IV 相同。几个氨基酸取代也改变了氨基酸性质，这可能会影响病毒感染和抗原性。这些结果为了解该流行地区的 DENV 遗传变异提供了线索，这可能与泰国 2015 年登革热疫情和大量登革出血热和登革休克综合征病例有关。
