title: NS2a-NS2b sequence analysis of DEN-4 virus strains.
abstract: To study the genetic variability of DEN-4 Chinese isolates, and to trace the origin of DV4 Chinese isolates, we cloned and sequenced the NS2a-NS2b junction of 5 isolates and prototype DV4 (H-241). Our results show that isolates from the 1990 Guangdong epidemic, which were isolated in the early, middle, and late periods of the epidemic, share the same sequence in the NS2a-NS2b junction. The sequence similarity between isolates from the Guangdong epidemic in 1990 and DV4 H-241 is 96%; these isolates can be grouped into genotype I. The sequence similarity between the isolate from the Guangdong epidemic in 1987 and Dominica strain 814669 is 96%; this isolate can be grouped into genotype II. For the first time, our results show that there are also 2 DV4 genotypes in the Guangdong area of southern China, and these isolates perhaps were introduced from other epidemic areas outside of China.
authors.affiliation: Department of Molecular Virology, Guangzhou Hygienic and Epidemic Prevention Institute, Guangzhou, PR China. yaohaijun@hotmail.com
authors.forename: Haijun
authors.initials: H
authors.lastname: Yao
authors.forename: Meiyu
authors.initials: M
authors.lastname: Fang
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Zhao
authors.forename: Fuqin
authors.initials: F
authors.lastname: Duan
authors.forename: Lihui
authors.initials: L
authors.lastname: Lin
authors.forename: Cuihua
authors.initials: C
authors.lastname: Chen
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D002681:China / Q000453:epidemiology; D018076:DNA, Complementary / Q000032:analysis; D003715:Dengue / Q000453:epidemiology / Q000821:virology*; D003716:Dengue Virus / Q000235:genetics*; D004196:Disease Outbreaks; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D017361:Viral Nonstructural Proteins / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; C080102:NS2B protein, flavivirus; D017361:Viral Nonstructural Proteins