title: Trypanosoma cruzi in Los Angeles and Miami blood donors: impact of evolving donor demographics on seroprevalence and implications for transfusion transmission.
abstract: BACKGROUND
  Trypanosoma cruzi, the agent of Chagas' disease, continues to be a concern for blood safety, as demonstrated by recent transfusion-transmitted cases in the United States and Canada. The chronic nature of Chagas', coupled with increasing numbers of immigrants from T. cruzi-endemic countries, suggests that Chagas' is a long-term public health problem. Herein, we report on a multiyear epidemiologic study of T. cruzi in Los Angeles and Miami blood donors.
  
  
  METHODS
  From May 1994 to September 1998, blood donors in Los Angeles and Miami were queried regarding birth or time spent in an endemic country. Donations of "yes" respondents were tested by EIA, confirmed by radioimmunoprecipitation assay, and if confirmed as seropositive, enrolled in look-back investigations.
  
  
  RESULTS
  A total of 1,104,030 Los Angeles and 181,139 Miami donors were queried regarding risk; 7.3 and 14.3 percent, respectively, responded yes. Seropositive rates were 1 in 7,500 Los Angeles and 1 in 9,000 Miami donors. In Los Angeles, seroprevalence rates increased significantly from 1996 to 1998 and were significantly higher for directed donors than nondirected donors. Look back identified 18 recipients, all of whom were seronegative for T. cruzi.
  
  
  CONCLUSIONS
  Significant numbers of T. cruzi-seropositive donors contribute to the U.S. blood supply. The incidence of seropositivity is enhanced by minority recruitment efforts necessitated by donor demographic shifts. Similarly, high rates among directed donations in Los Angeles are attributable to a disproportionate number of at-risk directed donors. Current look-back data likely underestimate the frequency of transfusion- transmitted T. cruzi. These results indicate that continued evaluation of transfusion as a mode of T. cruzi transmission in the United States is needed.
authors.affiliation: Transmissible Diseases Department, American Red Cross, Jerome H. Holland Laboratory, Rockville, MD 20855, USA. leibyd@usa.redcross.org
authors.forename: David A
authors.initials: DA
authors.lastname: Leiby
authors.forename: Ross M
authors.initials: RM
authors.lastname: Herron
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Read
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Lenes
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Stumpf
mesh_terms: D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001782:Blood Donors; D014355:Chagas Disease / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission; D004641:Emigration and Immigration; D005431:Florida / Q000453:epidemiology; D006630:Hispanic or Latino; D006801:Humans; D015994:Incidence; D007843:Latin America / Q000208:ethnology; D015141:Los Angeles / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D009927:Tissue and Organ Procurement / Q000706:statistics & numerical data; D065227:Transfusion Reaction; D014195:Travel; D014349:Trypanosoma cruzi / Q000276:immunology / Q000302:isolation & purification*; D014505:Urban Population
chemical_list: D000913:Antibodies, Protozoan