From Wikipedia, the free encyclopedia:
Human Herpesvirus Six (HHV-6) is one of the eight known viruses that are members of the human herpesvirus family. It causes the disease exanthem subitum (Roseola), a near-universal childhood disease.
HHV-6 is a member of the betaherpesviridae (subfamily of the herpesvirinae) which also includes HHV-7 and Cytomegalovirus (HHV-5 or HCMV). There are two subtypes of HHV-6 termed HHV-6A and HHV-6B.
HHV-6 has been reported in multiple sclerosis patients. and has been implicated as a co-factor in several other diseases, including chronic fatigue syndrome, fibromyalgia, AIDS, and temporal lobe epilepsy but no definitive link has been established.