Scrub typhus induced by peripheral blood stem cell transplantation in the immunocompromised patient: diagnostic usefulness of nested polymerase chain reaction.

Scrub typhus (Orientia tsutsugamushi) is a Gram-negative rickettsial disease in parts of Asia, transmitted from wild rodents to human by mites. This is a case report of scrub typhus contraction in an acute leukemia patient by transfusion of peripheral blood stem cells collected during the incubation period. Although human-to-human transmission of scrub typhus by needle-stick injury or transplacental transmission has previously been reported, this is the first case confirmed by polymerase chain reaction (PCR) and DNA sequencing. This type of incident shows the need to heighten awareness of the threat of rickettsial agents in transfused blood. Nested PCR is a useful diagnostic method to confirm the diagnosis during incubation period and in the early phase of disease, especially for immunocompromised patients.