title: Retrospective screening of acute undifferentiated fever serum samples with universal flavivirus primers.
abstract: BACKGROUND
  Fever is a common symptom of many tropical diseases and in many cases the etiologic agent remains unidentified as a consequence of either the etiologic agent not being part of routine diagnostic screening or as a consequence of false negatives on standard diagnostic tests.
  
  
  METHODS
  This study screened a well characterized panel of 274 serum samples collected on day of admission from adult patients with acute undifferentiated fever admitted to a hospital in Nakhon Ratchasima, Thailand by RT-PCR using pan-flavivirus degenerate primers.
  
  
  RESULTS
  Subsequent clinical diagnosis was achieved for 38 of the patients, and included 19 cases of dengue fever. RT-PCR screening identified seven positive samples (2.5%) which were revealed by sequence analysis to be dengue virus 1 (2 cases), dengue virus 2 (2 cases) and dengue virus 3 (3 cases). Only 5 out of 19 (26%) serum samples from patients subsequently diagnosed with dengue were positive, but 2 samples which clinically remained undiagnosed were shown to be positive for dengue virus. Sequence analysis suggested that the dengue virus 3 cases occurred as a result of importation of a strain of dengue from India or China. No other flaviviruses were identified.
  
  
  CONCLUSIONS
  No evidence was found of other flaviviruses besides dengue circulating in this population. Despite improved diagnostic tests, cases of dengue are still evading correct diagnosis.
authors.affiliation: Siriraj Hospital, Mahidol University, Bangkok, Thailand. sarawut_navy8@hotmail.com.
authors.forename: Sarawut
authors.initials: S
authors.lastname: Khongwichit
authors.forename: Sirikwan
authors.initials: S
authors.lastname: Libsittikul
authors.forename: Sutee
authors.initials: S
authors.lastname: Yoksan
authors.forename: Prasert
authors.initials: P
authors.lastname: Auewarakul
authors.forename: Yupin
authors.initials: Y
authors.lastname: Suputtamongkol
authors.forename: Duncan R
authors.initials: DR
authors.lastname: Smith
mesh_terms: D000328:Adult; D017931:DNA Primers / Q000235:genetics; D003716:Dengue Virus / Q000235:genetics / Q000302:isolation & purification*; D005335:Fever of Unknown Origin / Q000175:diagnosis*; D018178:Flaviviridae Infections / Q000175:diagnosis*; D006761:Hospitals; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D011446:Prospective Studies; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D044967:Serum / Q000821:virology*; D013785:Thailand
chemical_list: D017931:DNA Primers