The efficacy of photochemical treatment with methylene blue and light for the reduction ofTrypanosoma cruziin infected plasma

BACKGROUND AND OBJECTIVES: Chagas disease is a transfusion-transmitted infection. This study evaluates the efficacy of a methylene blue (MB) and light system for reducing the viability of Trypanosoma cruzi in plasma. MATERIALS AND METHODS Trypanosoma cruzi strains were spiked in plasma pools. Treatment arms included combined filtration, MB, light and freezing. Post-treatment parasite viability was assayed through in vitro cultures and in vivo inoculation in inducible nitric oxide synthase- and interferon-gamma-receptor-deficient mice. RESULTS: The filtration, MB and light combined treatment showed a log reduction of > 3.4 in in vitro cultures, and log reductions that ranged from > 4.9 to > 5.8 in deficient mice inoculated with different T. cruzi strains. CONCLUSION: The treatment of plasma units with the MB and light system reduces the T. cruzi burden and could be useful in preventing transfusion-transmitted Chagas disease.