Human herpes virus 6 fatal encephalitis in a bone marrow recipient.

Human herpes virus 6 (HHV-6) has been implicated as a human pathogen in both normal and immunocompromised hosts. It has been associated with interstitial pneumonitis and bone marrow suppression after transplantation. We report here a case of fatal encephalitis in a bone marrow transplant recipient. This case illustrates the importance of considering HHV6 as an emerging pathogen in immunocompromised hosts.