title: [Diagnosis of a dengue fever outbreak in Yiwu city, Zhejiang province in 2009 and its molecular tracing of the pathogen].
abstract: OBJECTIVE
  To determine a dengue fever outbreak in Yiwu city, Zhejiang Province in 2009 and to trace the origin of the pathogen.
  
  
  METHODS
  The dengue virus IgM, IgG antibodies and viral nucleic acid were detected and virus was isolated using 40 serum samples from the suspected patients. The viral RNA of the isolated virus strains was extracted and the E gene was amplified by RT-PCR. The amplicons were sequenced and the phylogenetic and homological analyses were also constructed.
  
  
  RESULTS
  Among 40 serum samples from dengue fever suspected patients, 17 were positive from for dengue IgM (42.5%); 4 were IgG positive (10.0%); 34 samples were dengue virus RNA positive (85.0%), 28 dengue virus type 3 (D3) strains were isolated (70.0%). The complete coding region of envelope genes (E) from 13 D3 strains was all 1479 nt without any insertion or deletion, which encoded with 493 amino acids (aa). E gene from the 13 D3 strains from Zhejiang in 2009 (D3/ZJ/2009) was 100.0% identical. The strain from Saudi Arabia shared the highest similarity with the D3 strain, 99.3% and 100.0% of their E genes and deduced amino acids were identical, respectively, whereas they were 93.4% and 97.4% between D3/ZJ/2009 strain and its prototype strain (D3/H87/1956), and 93.6% and 97.4% between D3/ZJ/2009 and a D3 strain isolated in Guangxi Province in 1980. The phylogenetic tree of E genes also indicated that D3/ZJ/2009 had maximum similarity with the D3/Saudi Arabia/2004. They all belonged to the D3/GIII branch, which was originated from Indian Subcontinent.
  
  
  CONCLUSIONS
  The outbreak of dengue fever in Zhejiang in 2009 was caused by type 3 dengue virus III genotype. The virus was most likely originated from Saudi Arabia.
authors.affiliation: Centers for Disease Control and Prevention of Zhejiang Province, Hangzhou 310051, China.
authors.forename: Ju-Ying
authors.initials: JY
authors.lastname: Yan
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Mao
authors.forename: Jun-Fen
authors.initials: JF
authors.lastname: Lin
authors.forename: Jing-Hua
authors.initials: JH
authors.lastname: Chen
authors.forename: Feng
authors.initials: F
authors.lastname: Ling
authors.forename: Xin-Ying
authors.initials: XY
authors.lastname: Wang
authors.forename: Yi-Yu
authors.initials: YY
authors.lastname: Lu
mesh_terms: D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D003715:Dengue / Q000453:epidemiology* / Q000821:virology*; D003716:Dengue Virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged