HUMAN-HERPESVIRUS-6 IS ASSOCIATED WITH FOCAL ENCEPHALITIS

Human herpesvirus 6 (HHV-6) is a cause of roseola infantum. Recent rep orts associate HHV-6 with cases of encephalitis; however, conclusive e tiologic data do not exist, We evaluated clinical data and laboratory specimens obtained from patients with focal encephalitis of unknown et iology, Cerebrospinal fluid (CSF) specimens were tested by polymerase chain reaction for the presence of HHV-6 DNA, Selected samples were an alyzed by DNA sequencing, We detected HHV-6 DNA in the CSF of nine of 138 patients. DNA sequencing revealed that group B strains of HHV-6 we re present in those specimens that were analyzed, No significant diffe rences could be demonstrated in clinical presentation, laboratory find ings, or neurodiagnostic imaging results between the nine patients wit h confirmed HHV-6 infection and the 129 patients without evidence of H HV-6 infection. Neurological outcome for the nine HHV-6-infected patie nts varied from complete recovery without neurological deficit to deat h, Further prospective study is warranted.