ABSTRACT
Human herpesvirus 6 (HHV-6) has been recognized as a human pathogen for over two decades since it was linked etiologically to the common childhood disease exanthem subitum (ES) or roseola infantum in 1988 [1]. Initial studies documented the widespread nature of infection, acquisition in early life, and the clinical characteristics of disease due to primary infection with HHV-6. Subsequent research has focused on identifying and understanding diseases due to HHV-6 reactivation in both normal and immunocompromised hosts of all ages. HHV-7 is closely related to HHV-6 and was rst isolated from a healthy adult in 1990 [2]. Since that time HHV-7 has been recognized as a cause of a subset of cases of exanthem subitum. Despite early suggestions that HHV-7 may play a substantial role in diseases in immunocompromised hosts, the full scope of disease due to HHV-7 remains unclear.
