"Over the years, numerous studies have demonstrated a link between  chronic viral infections and a number of conditions that alter brain  function. For example, research has shown a number of chronic viral  infections can be found in patients with Chronic Fatigue Syndrome (CFS).  Viruses such as Epstein-Barr virus (EBV), CMV, and several herpes  viruses (e.g., Herpes 1, 6, 7 – HSV-1, HHV-6, HHV-7) cause or contribute  to the symptoms of a large percentage of patient with CFS."   "Careful studies have shown 70% of patients with CFS had active HHV-6  infection through the use of primary cell cultures and confirmation  using assays of monoclonal antibodies specific for HHV-6 proteins and by  PCR. Moreover, a higher proportion of CFS patients have multiple  simultaneous infections, such as HHV-6 and HHV-7."    http://childpsychiatristdenver.com/biological-illnesses-childpsychiatristdenver/#bottom