title: First isolation of dengue virus from Lao PDR in a Chinese traveler.
abstract: BACKGROUND
  Epidemic dengue activity has been demonstrated in several southern regions of China, but not in Yunnan province, which borders countries in Southeast Asia where dengue is endemic. Many dengue cases imported from Southeast Asia to Yunnan have been reported, but dengue virus (DENV) has not been isolated from any patients. This study is the first to report the isolation of DENV from a Chinese traveler returning to Yunnan from Lao PDR.
  
  
  RESULTS
  A serum sample was collected from a patient presenting with a febrile illness who returned from Lao PDR in 2009 and was used to inoculate Aedes albopictus C6/36 cells for viral isolation. The viral isolate was identified using reverse transcription-polymerase chain reaction, and phylogenetic analyses based on the full E sequence were performed using Clustalx 1.8 software. The analyses detected DENV genome, and thus, a DENV isolate was obtained from the patient's serum sample. The new DENV isolate was grouped into genotype Asia 1, serotype 2. The viral E protein shared the greatest nucleotide sequence identity (99.6%) with the D2/Thailand/0606aTw strain isolated from Thailand in 2006 and demonstrated 94.3% to 100% identity with the predicted amino acid sequence of other DENV 2 strains.
  
  
  CONCLUSIONS
  Our findings indicate that DENV serotype 2 is circulating in Lao PDR, and surveillance of patients suspected of infection with dengue should be conducted not only by a serological test but also by pathogenic detection methods.
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People's Republic of China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Guo
authors.forename: Qiumin
authors.initials: Q
authors.lastname: Zhao
authors.forename: Chao
authors.initials: C
authors.lastname: Wu
authors.forename: Shuqing
authors.initials: S
authors.lastname: Zuo
authors.forename: Xiaoai
authors.initials: X
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Jia
authors.forename: Jiangyun
authors.initials: J
authors.lastname: Liu
authors.forename: Hongning
authors.initials: H
authors.lastname: Zhou
authors.forename: Jiusong
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000330:Aedes; D000818:Animals; D002681:China / Q000453:epidemiology; D003715:Dengue / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D003716:Dengue Virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007812:Laos / Q000453:epidemiology; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D014195:Travel; D055815:Young Adult