title: Genetic analysis of chikungunya viruses imported to mainland China in 2008.
abstract: BACKGROUND
  Chikungunya virus (CHIKV) has caused large outbreaks worldwide in recent years, especially on the islands of the Indian Ocean and India. The virus is transmitted by mosquitoes (Aedes aegypti), which are widespread in China, with an especially high population density in southern China. Analyses of full-length viral sequences revealed the acquisition of a single adaptive mutation providing a selective advantage for the transmission of CHIKV by this species. No outbreaks due to the local transmission of CHIKV have been reported in China, and no cases of importation were detected on mainland China before 2008. We followed the spread of imported CHIKV in southern China and analyzed the genetic character of the detected viruses to evaluate their potential for evolution.
  
  
  RESULTS
  The importation of CHIKV to mainland China was first detected in 2008. The genomic sequences of four of the imported viruses were identified, and phylogenetic analysis demonstrated that the sequences were clustered in the Indian Ocean group; however, seven amino acid changes were detected in the nonstructural protein-coding region, and five amino acid changes were noted in the structural protein-coding regions. In particular, a novel substitution in E2 was detected (K252Q), which may impact the neurovirulence of CHIKV. The adaptive mutation A226V in E1 was observed in two imported cases of chikungunya disease.
  
  
  CONCLUSIONS
  Laboratory-confirmed CHIKV infections among travelers visiting China in 2008 were presented, new mutations in the viral nucleic acids and proteins may represent adaptive mutations for human or mosquito hosts.
authors.affiliation: State Key Laboratory for Molecular Virology and Genetic Engineering, Institute for Viral Disease Control and Prevention, China CDC, 100 Yingxinjie, Xuanwu District, Beijing 100052, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Zheng
authors.forename: Jiandong
authors.initials: J
authors.lastname: Li
authors.forename: Quanfu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Mifang
authors.initials: M
authors.lastname: Liang
authors.forename: Chuan
authors.initials: C
authors.lastname: Li
authors.forename: Miao
authors.initials: M
authors.lastname: Lin
authors.forename: Jicheng
authors.initials: J
authors.lastname: Huang
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Dapeng
authors.initials: D
authors.lastname: Xiang
authors.forename: Ninlan
authors.initials: N
authors.lastname: Wang
authors.forename: Ye
authors.initials: Y
authors.lastname: Hong
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Li
authors.forename: Deguan
authors.initials: D
authors.lastname: Pan
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.forename: Jun
authors.initials: J
authors.lastname: Dai
authors.forename: Boxuan
authors.initials: B
authors.lastname: Guo
authors.forename: Dexin
authors.initials: D
authors.lastname: Li
mesh_terms: D000328:Adult; D018354:Alphavirus Infections / Q000453:epidemiology* / Q000821:virology*; D019943:Amino Acid Substitution / Q000235:genetics; D002646:Chikungunya virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014195:Travel; D014764:Viral Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins