Few subjects are more fraught with controversy than the role pathogens do or do not play in CFS. The flu-like symptoms often found at the onset and during the illness, as well as the immune abnormalities sometimes seen have long suggested a pathogenic origin to this disease but the many different pathogen triggers identified thus far (Epstein-Barr virus, coxsackie b, parvovirus, giardia, etc ) suggest the initial pathogen involved may be less important than something the pathogen does.
No arena of study has been more creative with researchers proposing unusual forms of Epstein-Barr Virus, HHV-6 and enteroviruses are causing distress in chronic fatigue syndrome.
Sophisticated studies underway in 2012 by the Chronic Fatigue Initiative, CFIDS Association of America, CDC and Whittemore Peterson Institute should shed light on the role pathogens may play in this disease.
The Herpes Viruses: Hesperviridae
The herpesviruses or herpes virus family come first in this series of papers on the pathogens in chronic fatigue syndrome (ME/CFS) for a good reason; no other family of viruses has come close to receiving the kind of attention that this group of viruses has. The tale of the herpesviruses in ME/CFS with their rises and falls, their identity questions, and now their seeming re-emergence from the ‘dead files’, have all the complexity of a Greek play.
Most herpesvirus activity is benign and goes unnoticed but herpes virus activation can be associated with a wide variety of disturbing conditions including encephalitis/meningitis (HSVI and II, HHV6-B), shingles, chicken pox (varicella zoster virus), hearing loss, mononucleosis (Epstein Barr virus, post-viral fatigue (EBV)), Karposi’s sarcoma (HHV8), and atherosclerosis, hearing loss, mental retardation, retinitis (human cytomegalovirus – (HMCV)), chronic fatigue syndrome (HHV-6) and multiple sclerosis (HHV-6, EBV). (De Bolle et. al. 2005).
Except for HHV2 and HHV8 all the herpesviruses are commonly found in the human population and all share an important characteristic; the ability to hide out from the immune system in a latent state in the body for long periods and then re-emerge during times of immunosuppression.
- Human Herpesvirus Six (HHV-6) – No pathogens have received more attention in CFS than the peculiar family of viruses called the Herpesviruses, and no pathogen has received more attention than Human Herpesvirus Six (HHV-6)
- Epstein-Bar Virus – more CFS patients appear to become ill after a bout with EBV than any other pathogen. Check out a four part series on the biggest trigger in ME/CFS.
- Varicella Zoster – A different herpes virus for CFS?
- Enteroviruses – Enteroviruses were the ‘first’ pathogen suspected in this disorder and the first to fall out of favor but dogged work by Dr. John Chia brought them back into the discussion. The enteroviruses associated with ME/CFS are coxsackievirus B and echovirus.
- Giardia – a early outbreak study pegged giardia as the only pathogen that was definitively associated with an outbreak. Almost 20 years later another study suggested it could be as well.
- XMRV – Many negative studies and some elegant detective work at the National Cancer Institute and other, indicated that XMRV did not play a role in causing ME/CFS. From the publication of the October, 2009 paper until the Blood Working group at the end of 2011 it was wild ride indeed.