The viral origin of myalgic encephalomyelitis/chronic fatigue syndrome

ME/CFS is a disabling and often severe disease, so-far incurable, that has long been associated with discrete outbreaks and sporadic incidents of viral-like illness.First, a word about the controversial name.The designation "Myalgic Encephalomyelitis" (abbreviated ME) originated following an outbreak at London's Royal Free Hospital in 1955.More than 200 members of the hospital staff became disabled [1].Melvin Ramsay, MD, eventually published important case descriptions in Lancet [2].He coined "ME" based on predominant symptoms of muscle pain (myalgia) and effects on the brain (encephalo), spinal cord (myel), and inflammation (itis).For 32 years, "ME" was deemed acceptable until, in 1987, the Centers for Disease Control (CDC) convened an extramural committee to change the name.CDC did so in response to a series of outbreaks of a similar, if not identical, illness in the United States, introducing "chronic fatigue syndrome" in 1988 [3].Because the CDC name trivializes the serious nature of the disease, the patient community and many medical professionals prefer ME, which continues to be widely used in the United Kingdom and Europe.In 2015, a US Institute of Medicine (IOM) committee recommended yet another name, Systemic Exertion Intolerance Disease [4], which has been largely ignored.Should inflammation of the brain and spinal cord be definitively shown with modern methods, the name Myalgic Encephalomyelitis will finally be vindicated.The compromise name ME/ CFS is now used most frequently and will be used here despite its faults. Can any infection lead to ME/CFS?AU : PleaseconfirmthatallheadinglevelsarerepThere is actually no proof that multiple different pathogens can cause ME/CFS.Yet, this hypothesis persists largely due to the overinterpretation of data from at least 2 studies.The limited evidence depends on how ME/CFS is defined.Currently, research groups and clinicians typically use any one of 3 definitions: the so-called Fukuda criteria (CDC's 1988 criteria) [3], the Canadian Consensus Criteria of 2003 [4], and criteria suggested by the IOM committee [5].Of these, the Fukuda criteria are considered somewhat obsolete, as there is no requirement for core symptoms [6].The 2015 IOM Committee required (1) impaired ability to engage in pre-illness activity levels that lasts for more than 6 months; (2) increased symptoms following physical, mental, or emotional exertion that would have been tolerated pre-illness (post-exertional malaise); and (3) unrefreshing sleep.For diagnosis, an individual must also exhibit either cognitive impairment and/or orthostatic intolerance [5] (Fig 1).A 2006 Australian study is oft cited as proof that virtually any number of infections cause ME/CFS.Researchers followed 253 people in Dubbo for 12 months.Of these, 171 had verified acute Epstein-Barr virus infection, Q fever (caused by Coxiella burnetii), or Ross River virus infections, while 82 were suspected of having one of these infections.Nine percent of the