The episodic vertigo of Meniere's disease is related to stress. Although the questionnaire method is useful in the evaluation of mental stress, it is hard to assess physical stress, in other words, fatigue. Human herpes virus-6 (HHV-6) and -7 (HHV-7) are the cause of Roseola infantum. Latent infection of those viruses is established in all Japanese adults, and viruses are re-activated and secreted into saliva under conditions of severe fatigue. Detection of HHV-6 DNA in saliva represents short-term fatigue which lasts for a week, and that of HHV-7 DNA indicates long-term fatigue which lasts for a month. Objective evaluation of fatigue is achieved by measurement of the levels of HHV-6 and 7 DNA in saliva. Patients who suffered from vertigo attacks within a week were divided into two groups, namely Meniere's disease with depression (D (+) Meniere) and without depression (D (-) Meniere), using questionnaires and investigation of mental problems. Saliva samples were collected, and viral DNA was amplified with the Loop mediated isothermal amplification method using specific primers as reported previously. HHV-7 DNA was detected at the high rate of 89% in the D (-) Meniere group, whereas it was 17% in the D (+) Meniere group, and 0% in healthy subjects. HHV-6 DNA was also detected at a higher rate of 64% in the D (-) Meniere group compared with 17% in the D (+) Meniere group and 33% in healthy subjects. A high rate of virus DNA in saliva indicated accumulated fatigue in Meniere's disease patients.
