title: Epidemiologic and laboratory findings from 3 years of testing United States blood donors for Trypanosoma cruzi.
abstract: BACKGROUND
  At most blood centers in the United States routine testing of donations for Trypanosoma cruzi using an enzyme-linked immunosorbent assay (ELISA) is followed by supplemental testing by radioimmunoprecipitation assay (RIPA). The objective of this study was to report the results of routine testing and risk factor data from allogeneic blood donors.
  
  
  METHODS
  T. cruzi testing data from January 2007 through December 2009 were analyzed, and risk factor interviews and follow-up studies were conducted on seroreactive donors. Prevalences of confirmed infection and risk factors associated with infection were assessed using logistic and multivariable logistic regression.
  
  
  RESULTS
  Of 2,940,491 allogeneic donations from 1,183,076 donors, 305 (0.01% per donation tested and 0.026% per blood donor) were repeat reactive (RR) and 89 of those were confirmed positive by RIPA, yielding an overall seroprevalence of 1 per 33,039 donations and 1 per 13,292 donors. Country of birth and US blood center location differences in the seroprevalence of T. cruzi were evident. The odds of confirmed infection were highest if the donor reported having been bitten by the reduviid (kissing) bug (odds ratio [OR], 76.1; 95% confidence interval [CI], 11.1-3173) followed by having lived in a rural area of Latin America (OR, 38.6; 95% CI, 15.1-102.5). In multivariable analyses, having spent 3 months or more in Mexico or Central and/or South America was associated with the highest odds of RIPA-confirmed infection (OR, 8.5; 95% CI, 2.7-26.5). Polymerase chain reaction (PCR) testing of ELISA RR donors exhibited low sensitivity (1/22 [4%] RIPA-confirmed donors was PCR positive).
  
  
  CONCLUSIONS
  Risk factors for confirmed infection in US blood donors are consistent with the known epidemiology of Chagas disease. Blood donors or transfusions do not substantially contribute to the burden of T. cruzi infection in the United States.
authors.affiliation: Blood Systems Research Institute, San Francisco, California 94118, USA. bcuster@bloodsystems.org
authors.forename: Brian
authors.initials: B
authors.lastname: Custer
authors.forename: Maria
authors.initials: M
authors.lastname: Agapova
authors.forename: Roberta
authors.initials: R
authors.lastname: Bruhn
authors.forename: Robin
authors.initials: R
authors.lastname: Cusick
authors.forename: Hany
authors.initials: H
authors.lastname: Kamel
authors.forename: Peter
authors.initials: P
authors.lastname: Tomasulo
authors.forename: Hope
authors.initials: H
authors.lastname: Biswas
authors.forename: Leslie
authors.initials: L
authors.lastname: Tobler
authors.forename: Tzong-Hae
authors.initials: TH
authors.lastname: Lee
authors.forename: Sally
authors.initials: S
authors.lastname: Caglioti
authors.forename: Michael
authors.initials: M
authors.lastname: Busch
mesh_terms: D000328:Adult; D000818:Animals; D001782:Blood Donors / Q000706:statistics & numerical data*; D001803:Blood Transfusion / Q000706:statistics & numerical data; D014355:Chagas Disease / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology* / Q000469:parasitology; D019411:Clinical Laboratory Techniques / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006403:Hematologic Tests / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data*; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D013997:Time Factors; D065227:Transfusion Reaction; D014349:Trypanosoma cruzi / Q000276:immunology / Q000302:isolation & purification*; D014481:United States / Q000453:epidemiology; D055815:Young Adult