title: Virus and antibody dynamics in acute west nile virus infection.
abstract: BACKGROUND
  The dynamics of the early stages of West Nile virus (WNV) infection can be assessed by follow-up studies of viremic blood donors.
  
  
  METHODS
  A total of 245 donors with WNV viremia were followed up weekly for 4 weeks and then monthly for up to 6 additional months or until seroconversion. Plasma samples were tested for WNV RNA by transcription-mediated amplification (TMA) and for WNV-specific IgM and IgG antibodies. RNA persistence was investigated by 6 replicate TMA tests; samples that were viremic for >40 days were tested for WNV-neutralizing activity. Follow up of 35 additional viremic donors for up to 404 days was conducted to evaluate persistence of WNV-specific antibody.
  
  
  RESULTS
  The median time from RNA detection to IgM seroconversion was 3.9 days; to IgG seroconversion, 7.7 days; to RNA negativity by single-replicate TMA, 13.2 days; and to RNA negativity by 6-replicate TMA, 6.1 additional days after results of single-replicate TMA are negative. For 4 donors in whom RNA persisted for >40 days after the index donation, all samples obtained after this threshold were also positive for WNV IgG and neutralizing activity. The mean times to IgM and IgA negativity were 156 and 220 days, respectively.
  
  
  CONCLUSIONS
  IgM and IgG develop rapidly after viremia and before RNA levels become undetectable, which occurred a mean of 13.2 days after the index donation among donors in this study. WNV RNA detection by replicate TMA rarely persists for >40 days after the index donation and is accompanied by WNV-specific neutralizing antibody, consistent with an absence of WNV transmission via transfusion of seropositive blood components.
authors: Blood Systems Research Institute, San Francisco, CA 94118, USA. MBusch@bloodsystems.org
authors: Michael P
authors: MP
authors: Busch
authors: Steven H
authors: SH
authors: Kleinman
authors: Leslie H
authors: LH
authors: Tobler
authors: Hany T
authors: HT
authors: Kamel
authors: Philip J
authors: PJ
authors: Norris
authors: Irina
authors: I
authors: Walsh
authors: Jose L
authors: JL
authors: Matud
authors: Harry E
authors: HE
authors: Prince
authors: Robert S
authors: RS
authors: Lanciotti
authors: David J
authors: DJ
authors: Wright
authors: Jeffrey M
authors: JM
authors: Linnen
authors: Sally
authors: S
authors: Caglioti
mesh_terms: D000208:Acute Disease; D000914:Antibodies, Viral / Q000097:blood*; D001782:Blood Donors; D006801:Humans; D009500:Neutralization Tests; D021141:Nucleic Acid Amplification Techniques; D012367:RNA, Viral / Q000097:blood; D065227:Transfusion Reaction; D014901:West Nile Fever / Q000276:immunology / Q000821:virology*; D014902:West Nile virus / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral