[Chronic fatigue syndrome and herpesvirus reactivation].

Human herpesvirus 6(HHV-6) and human herpesvirus 7(HHV-7) establish life-long latency, reactivate frequently, and are shed in saliva. To identify the factor(s) of their reactivation, we have studied the association with the reactivation and fatigue. Reactivation was examined for viral DNA by real-time PCR method. As a result, healthy adults shed the reactivated HHV-6 in the saliva during work -induced fatigue, and the copy number of HHV-6 DNA was reduced after holidays. However, no significant HHV-6 DNA increase was observed in chronic fatigue syndrome (CFS) patients. In contrast, increase of HHV-7 reactivation was observed both in the case of work-induced fatigue and CFS. These findings suggest that the amount of HHV-6 and HHV-7 reactivation can be an objective biomarker for fatigue.