title: Detection of West Nile virus in the Mexican blood supply.
abstract: BACKGROUND
  West Nile virus (WNV) is the etiologic agent of an emerging disease in the Western Hemisphere that can be transmitted to humans by blood transfusion. WNV first appeared in the United States in 1999, in Canada in 2001, and in Mexico in 2002. The aim of this nationwide study was to determine the prevalence of WNV in blood donors in Mexico as a first step in preventing its transfusion-associated transmission.
  
  
  METHODS
  In July and August 2004, a total of 3856 fresh plasma specimens collected from each state's center for blood transfusion in 29 of 31 Mexican states were screened with an investigational WNV assay (Procleix,(R) Gen-Probe Inc. and Chiron Corp.), a nucleic acid test based on transcription-mediated amplification (TMA). Reactive specimens were confirmed with a second TMA-based test, the alternative WNV assay (Gen-Probe), and with WNV capture enzyme-linked immunosorbent assays (ELISAs) for detection of immunoglobulin M (IgM) and IgG antibodies. In addition, 3714 frozen plasma samples collected in 2002 and 2003 were similarly tested.
  
  
  RESULTS
  One of 3856 fresh samples from an asymptomatic donor from Chihuahua was reactive by both TMA-based tests and IgM ELISA, suggesting a recently acquired infection. The observed percentage of viremic donors blood donors was 0.03 percent. Results from frozen samples were not included in the prevalence calculation and none were TMA-reactive for WNV.
  
  
  CONCLUSIONS
  WNV is present in the Mexican blood supply and measures should be taken to reduce the risk of transfusion transmission.
authors.affiliation: National Center for Blood Transfusion, Mexico City, Mexico. sasanche@avantel.net
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Sánchez-Guerrero
authors.forename: Sagrario
authors.initials: S
authors.lastname: Romero-Estrella
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodríguez-Ruiz
authors.forename: Lilia
authors.initials: L
authors.lastname: Infante-Ramírez
authors.forename: Angélica
authors.initials: A
authors.lastname: Gómez
authors.forename: Eduardo
authors.initials: E
authors.lastname: Villanueva-Vidales
authors.forename: Martha
authors.initials: M
authors.lastname: García-Torres
authors.forename: Ana M A
authors.initials: AM
authors.lastname: Domínguez
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Vázquez
authors.forename: Eva D
authors.initials: ED
authors.lastname: Calderón
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Valiente-Banuet
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Linnen
authors.forename: Amy
authors.initials: A
authors.lastname: Broulik
authors.forename: William
authors.initials: W
authors.lastname: Harel
authors.forename: Rafael A
authors.initials: RA
authors.lastname: Marín Y López
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D001769:Blood / Q000821:virology; D001771:Blood Banks; D001782:Blood Donors; D001803:Blood Transfusion; D021821:Communicable Diseases, Emerging / Q000097:blood* / Q000517:prevention & control; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008800:Mexico; D012367:RNA, Viral / Q000097:blood*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014901:West Nile Fever / Q000097:blood* / Q000517:prevention & control / Q000635:transmission; D014902:West Nile virus
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral