Blood transfusion transmission of the tick-borne relapsing fever spirochete Borrelia miyamotoi in mice.

BACKGROUND: Borrelia miyamotoi, a recently discovered relapsing fever spirochete, occurs in hard-bodied ticks wherever Lyme disease is endemic. Human infection is associated with relapsing fever and can cause meningoencephalitis in immunocompromised patients. A few cases of transfusion transmission of other relapsing fever spirochete species have been reported but none for B. miyamotoi. Our objective was to determine whether B. miyamotoi transfusion transmission could occur in a murine transfusion model. Herein, we report transfusion transmission of B. miyamotoi through fresh or stored red blood cells (RBCs) in a mouse model.

STUDY DESIGN AND METHODS: Inbred mice were transfused with B. miyamotoi-infected murine blood that was either freshly collected or stored for 7 days before transfusion. Recipient blood was then longitudinally examined after transfusion by smear and wet mount for evidence of spirochetemia.

RESULTS: Motile spirochetes were observed in immunocompromised (SCID) mouse recipients for 28 days after transfusion of both fresh and stored murine B. miyamotoi-infected RBCs. Transient spirochetemia was observed in immunocompetent DBA/2 and C57BL/6 mice, with spirochete clearance occurring within 5 days after transfusion.

CONCLUSION: These data demonstrate that transfusion transmission of B. miyamotoi can occur in mice and suggest that it also may occur in humans.