Human herpesvirus-6 DNA in cerebrospinal fluid of a child with exanthem subitum and meningoencephalitis.

The involvement of human herpesvirus-6 (HHV-6) and herpes simplex virus infections was evaluated virologically and serologically in a 13-month-old girl with meningoencephalitic illness occurring in the pre-eruptive stage of exanthem subitum. An isolation of HHV-6 from blood and seroconversion to the virus confirmed the primary infection with the virus. HHV-6 gene sequences were detected in cerebrospinal fluid of acute stage of the disease by polymerase chain reaction. There was no evidence of herpes simplex virus infection in blood and cerebrospinal fluid. The patient recovered from the disease without any sequelae, although abnormal electroencephalography and cerebral computed tomography findings were observed temporally in the acute stage of the disease. These findings strongly suggest that HHV-6 invades the central nervous system and causes meningoencephalitis.