Reduction of Leishmania donovani infectivity in whole blood using riboflavin and ultraviolet light.

Background Leishmaniasis is a vector-borne disease caused by the protozoan parasite Leishmania sp. that is transmitted by sandflies. Travelers to endemic areas, and US military personnel stationed in the Middle East, are at risk for contracting the disease. Study Design and Methods Whole blood (WB) units were spiked with human monocytes infected with L. donovani amastigotes to a final concentration of approximately 105 infected cells/mL. After riboflavin (RB) addition, units were exposed to 80 J/mLRBCs ultraviolet (UV) light. One pretreatment (collected after RB addition) and one posttreatment sample were collected, serially diluted in culture medium, and incubated at 22°C for up to 5 weeks. Parasite viability was determined by microscopic observation for replicating promastigote forms. Results Mirasol treatment of 3 units of L. donovani–infected WB with RB and UV light resulted in a parasite reduction of 2.3 ± 0.12 log. Conclusions Partial reduction of L. donovani can be achieved in WB using RB and UV light. This technology may be useful when potential donors are exposed to Leishmania sp. during residence, travel, or military deployment to an endemic area.