Background: Babesia microti is an intraerythrocytic parasite, transmitted naturally to humans by infected ixodid ticks, that causes babesiosis. In recent years, B. microti has been identified as a growing public health concern that has also emerged as a critical blood safety issue in the absence of appropriate interventions to reduce transmission by blood transfusion. Thus, we evaluated the ability of the Mirasol pathogen reduction technology (PRT; CaridianBCT), which uses riboflavin (RB) and ultraviolet (UV) light, to diminish the presence of B. microti in apheresis plasma and platelets (PLTs).
Study design and methods: Apheresis plasma and PLT units were spiked with B. microti-infected hamster blood and subsequently treated using the Mirasol PRT system. Control and experimental samples were collected at different stages during the treatment process and injected into hamsters to detect the presence of viable parasites. Four weeks postinoculation, hamster blood was tested for B. microti infection by blood smear and real-time polymerase chain reaction analysis.
Results: None of the blood smears from animals injected with samples from PRT-treated plasma or PLT units were positive by microscopy, while all the non-PRT-treated plasma and PLT units were demonstrably parasitemic. Parasite load reduction in hamsters ranged between 4 and 5 log in all PRT-treated units compared to untreated controls.
Conclusion: The data indicate that the use of RB and UV light efficiently reduces the presence of viable B. microti in apheresis plasma and PLT products, thereby reducing the risk of transfusion-transmitted Babesia potentially associated with these products. Based on this observed "proof of principle," future studies will determine the efficacy of the Mirasol PRT in whole blood.