title: Inactivation of Plasmodium falciparum in whole blood by riboflavin plus irradiation.
abstract: BACKGROUND
  Malaria parasites are frequently transmitted by unscreened blood transfusions in Africa. Pathogen reduction methods in whole blood would thus greatly improve blood safety. We aimed to determine the efficacy of riboflavin plus irradiation for treatment of whole blood infected with Plasmodium falciparum.
  
  
  METHODS
  Blood was inoculated with 10(4) or 10(5) parasites/mL and riboflavin treated with or without ultraviolet (UV) irradiation (40-160 J/mL red blood cells [mL(RBCs)]). Parasite genome integrity was assessed by quantitative amplification inhibition assays, and P. falciparum viability was monitored in vitro.
  
  
  RESULTS
  Riboflavin alone did not affect parasite genome integrity or parasite viability. Application of UV after riboflavin treatment disrupted parasite genome integrity, reducing polymerase-dependent amplification by up to 2 logs (99%). At 80 J/mL(RBCs), riboflavin plus irradiation prevented recovery of viable parasites in vitro for 2 weeks, whereas untreated controls typically recovered to approximately 2% parasitemia after 4 days of in vitro culture. Exposure of blood to 160 J/mL(RBCs) was not associated with significant hemolysis.
  
  
  CONCLUSIONS
  Riboflavin plus irradiation treatment of whole blood damages parasite genomes and drastically reduces P. falciparum viability in vitro. In the absence of suitable malaria screening assays, parasite inactivation should be investigated for prevention of transfusion-transmitted malaria in highly endemic areas.
authors: Department of Haematology, University of Cambridge, Cambridge, United Kingdom; Department of Immunology & Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom; HPA Malaria Reference Laboratory, London School of Hygiene & Tropical Medicine, London, United Kingdom; Faculty of Health Sciences, University of Balamand, Beirut, Lebanon.
authors: Mira
authors: M
authors: El Chaar
authors: Sharan
authors: S
authors: Atwal
authors: Graham L
authors: GL
authors: Freimanis
authors: Bismarck
authors: B
authors: Dinko
authors: Colin J
authors: CJ
authors: Sutherland
authors: Jean-Pierre
authors: JP
authors: Allain
mesh_terms: D058731:Blood Safety; D006801:Humans; D008288:Malaria / Q000097:blood / Q000469:parasitology; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000528:radiation effects*; D012256:Riboflavin / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D012256:Riboflavin