The enterovirus theory of disease etiology in Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome: a critical review, by Adam J O’Neal and Maureen R Hanson in Front. Med., 18 June 2021 [doi.org/10.3389/fmed.2021.688486]
Research review abstract:
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex, multi-system disease whose etiological basis has not been established.
Enteroviruses (EVs) as a cause of ME/CFS have sometimes been proposed, as they are known agents of acute respiratory and gastrointestinal infections that may persist in secondary infection sites, including the central nervous system, muscle, and heart.
To date, the body of research that has investigated enterovirus infections in relation to ME/CFS supports an increased prevalence of chronic or persistent enteroviral infections in ME/CFS patient cohorts than in healthy individuals. Nevertheless, inconsistent results have fuelled a decline in related studies over the past two decades.
This review covers the aspects of ME/CFS pathophysiology that are consistent with a chronic enterovirus infection and critically reviews methodologies and approaches used in past EV-related ME/CFS studies. We describe the prior sample types that were interrogated, the methods used and the limitations to the approaches that were chosen.
We conclude that there is considerable evidence that prior outbreaks of ME/CFS were caused by one or more enterovirus groups. Furthermore, we find that the methods used in prior studies were inadequate to rule out the presence of chronic enteroviral infections in individuals with ME/CFS.
Given the possibility that such infections could be contributing to morbidity and preventing recovery, further studies of appropriate biological samples with the latest molecular methods are urgently needed.
Excerpts from Discussion:
Many ME/CFS patients in a variety of studies indicate a viral-like illness immediately preceded their ME/CFS symptoms. However, surveys also indicate that patients ascribe their onset to a variety of other reasons, including emotional stress, life events, recent travel, accidents, toxic substances, or mold. However, some of these events and exposures could merely be coincidental and actually be due to an enteroviral infection that was unnoticed or very mild, given that many enteroviral infections are asymptomatic.
The COVID19 pandemic has made it obvious that persistent symptoms can arise from mild or asymptomatic infections. Were the existence of SARS CoV-2 not known, many of the individuals with long-lasting symptoms of COVID 19 might readily have ascribed their mysterious illness to some other factor than viral infection.
It is evident that more research must be conducted in order to determine whether or not the majority of pre-2020 ME/CFS cases have arisen from EV infection. At the time of this writing, there have been a number of anecdotal reports of individuals experiencing remission of long-term COVID19 symptoms after receiving anti-SARS COV2 vaccines. Such a therapy will not be possible for any ME/CFS patients whose illness is due to chronic infection unless the persistent virus is identified.