title: Isolation and genetic characteristics of human genotype 1 Japanese encephalitis virus, China, 2009.
abstract: BACKGROUND
  Several studies have shown that the predominant genotype of Chinese Japanese encephalitis virus (JEV) is evolving from genotype 3 to genotype 1. However, in recent years, almost all genotype 1 isolates were from mosquitoes, and genotype 1 has been less associated with human disease than genotype 3. This study reports the isolation of human genotype 1 JEV and its genetic characteristics to provide additional insights into human JE pathogens that are currently circulating in China.
  
  
  RESULTS
  In 2009, 31 cerebrospinal fluid samples were collected from patients living in Yunnan and Shanxi provinces and were used to inoculate Aedes albopictus C6/36 cells for virus isolation. The JEV strains were identified using immunofluorescent assays and the reverse transcription-polymerase chain reaction. Phylogenetic analyses based on the partial capsid/pre-membrane and full envelope (E) sequences were performed using Clustalx 1.8 software. Three JEV isolates were obtained from a 4-year-old girl and a 2-year-old boy living in Yunnan and an 82-year-old woman in Shanxi. The boy had been immunized with one dose of JE live attenuated vaccine. New isolates were grouped into genotype 1. Amino acid sequence for the viral E protein indicated 95% to 100% identity with each other and with other JEV strains. When compared with a consensus sequence of E protein, two amino acid substitutions were found: Ser(E-123)-Asn in the two Yunnan isolates and Lys(E-166)-Arg in the Shanxi isolate.
  
  
  CONCLUSIONS
  Our findings indicate that the genotype 1 of JEV is causing human infections in China. Our observation of a previously vaccinated boy developing JE from genotype 1 virus infection also calls for more detailed studies, both in vitro and in vivo neutralization tests as well as active surveillance, to examine the possibility of a lack of complete protection conferred by the live attenuated JE vaccine against genotype 1 virus.
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People's Republic of China. zhang_jiusong@yahoo.com.cn
authors.forename: Jiu-Song
authors.initials: JS
authors.lastname: Zhang
authors.forename: Qiu-Min
authors.initials: QM
authors.lastname: Zhao
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Guo
authors.forename: Shu-Qing
authors.initials: SQ
authors.lastname: Zuo
authors.forename: Jing-Xia
authors.initials: JX
authors.lastname: Cheng
authors.forename: Na
authors.initials: N
authors.lastname: Jia
authors.forename: Chao
authors.initials: C
authors.lastname: Wu
authors.forename: Pei-Fang
authors.initials: PF
authors.lastname: Dai
authors.forename: Jun-Ying
authors.initials: JY
authors.lastname: Zhao
mesh_terms: D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D002648:Child; D002675:Child, Preschool; D002681:China; D004664:Encephalitis Virus, Japanese / Q000235:genetics / Q000302:isolation & purification*; D004672:Encephalitis, Japanese / Q000821:virology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D010802:Phylogeny; D014613:Vaccines, Attenuated / Q000494:pharmacology; D014764:Viral Proteins / Q000235:genetics
chemical_list: D014613:Vaccines, Attenuated; D014764:Viral Proteins