title: Evaluating pathogen reduction of Trypanosoma cruzi with riboflavin and ultraviolet light for whole blood.
abstract: BACKGROUND
  Trypanosoma cruzi, the protozoan parasitic agent of Chagas disease, can be transmitted by blood transfusion. In 2007, most US blood banks started screening blood donations for T. cruzi, but the cost and perceived need of the test have been the subject of ongoing discussion. In this study, we evaluated the ability of the Mirasol System (CaridianBCT), which uses riboflavin (RB) and ultraviolet light to inactivate pathogens, to reduce the levels of infectious T. cruzi in whole blood (WB).
  
  
  METHODS
  WB units were inoculated with 4, 40, 400, and 4000 trypomastigotes/mL. After addition of RB and illumination at various energy levels, the samples were tested for the presence of live parasites by hemoculture.
  
  
  RESULTS
  All preillumination samples exhibited T. cruzi growth in hemoculture, while postillumination samples from units containing 4 and 40 trypomastigotes/mL showed no signs of viable parasites after 16 weeks of culture. In contrast, at both 400 and 4000 parasites/mL, two of the three units were positive for viable parasites.
  
  
  CONCLUSIONS
  The total log reduction observed for T. cruzi was 3.5 log or greater, but less than 4.5 log. This level of reduction is likely to be orders of magnitude higher than what would be expected in a tainted blood donation, indicating that the Mirasol System could be effective at preventing transfusion of the causative agent of Chagas disease.
authors.affiliation: Transmissible Diseases Department, Jerome H. Holland Laboratory, American Red Cross, Rockville, Maryland 20855, USA. tonnettil@usa.redcross.org
authors.forename: Laura
authors.initials: L
authors.lastname: Tonnetti
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Thorp
authors.forename: Heather L
authors.initials: HL
authors.lastname: Reddy
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Keil
authors.forename: Raymond P
authors.initials: RP
authors.lastname: Goodrich
authors.forename: David A
authors.initials: DA
authors.lastname: Leiby
mesh_terms: D016475:3T3 Cells; D000465:Algorithms; D000818:Animals; D001782:Blood Donors; D017848:Blood-Borne Pathogens / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D014355:Chagas Disease / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control / Q000635:transmission; D004202:Disinfectants / Q000627:therapeutic use; D006801:Humans; D051379:Mice; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D059208:Parasite Load; D012256:Riboflavin / Q000627:therapeutic use*; D013242:Sterilization / Q000379:methods*; D014349:Trypanosoma cruzi / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D014466:Ultraviolet Rays
chemical_list: D004202:Disinfectants; D012256:Riboflavin