The way I have been looking at it, brain fog is a component of chronic "subclinical" encephalitis (or more appropriately perhaps encephalopathy). When it all boils down it is the lethargy, the mental fatigue and the cognitive dsyfunction which are the main components of disability and reduced QOL with CFS. So the research on encephalitis and HHV-6 (much of which can be related to reactivations rather than acute encephalitis) is quite critical to the whole topic of CFS.
Dr Jon Wilcox, what is your view on enteroviruses such as coxsackievirus B causing a low-level infection of the brain leading to ME/CFS? CVB has been shown capable of infecting the astrocyte cells of the mouse brain (ref:
1), and infecting neuronal progenitor cells (ref:
1).
A lot of people look to HHV-6 as the main culprit in ME/CFS. However, many people develop ME/CFS in their 20s and 30s after catching a respiratory virus, and this virus is unlikely to be HHV-6, because most humans will pick up HHV-6 much earlier in life, typically before the age of 3. Thus the virus that triggers ME/CFS would need to be a virus that is not acquired early in life, but one that is typically acquired in the 20s and 30s. The six serotypes of coxsackievirus B are good candidates for such a virus acquired later in life.
Of course, with coxsackievirus B being immunosuppressive, this could lead to the reactivation of HHV-6, EBV, CMV, etc.
