Abstract

Chronic Fatigue Syndrome / Myalgic Encephalomyelitis (CFS/ME) is a disease characterised by severe and debilitating fatigue, sleep abnormalities, impaired memory and concentration, and musculoskeletal pain. In the Western world, the population prevalence is estimated to be of the order of 0.5%. Research studies have identified various features relevant to the pathogenesis of CFS/ME such as viral infection, immune abnormalities and immune activation, exposure to toxins, chemicals and pesticides, stress, hypotension, lymphocyte abnormalities and neuroendocrine dysfunction. However, the precise underlying disease mechanisms and means by which these abnormalities inter-relate in CFS/ME patients, remain to be clarified. Various viruses have been shown to play a triggering or perpetuating role, or both, in this complex disease. Microbes which have been shown to trigger CFS/ME include enteroviruses, Epstein-Barr virus, Chlamydia pneumoniae, parvovirus B19, Coxiella burnetii, Borna disease virus, Varicella Zoster virus, cytomegalovirus, and human herpesvirus type 6 (HHV-6). Chronic microbial infections which have been documented in CFS/ME patients include Coxiella burnetii, parvovirus B19, Chlamydia pneumoniae, hepatitis C, enteroviruses and human retroviruses. Virus reactivations in CFS/ME include Varicella-Zoster virus, Herpes Simplex virus (HSV) (increased frequency of cold sores) and EBV.