Current Insights into Complex Post-Infection Fatigue Syndromes with Unknown Aetiology: the Case of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Beyond

Black plague epidemics in Medieval Europe, the devastating Spanish Flu’s during the first world war, and the ongoing pandemic of COVID-19 are just three well-known examples of the fragile co-existence between us human beings and the invisible microbial world. In most infections, our immune system is able to recognize and clear the invading pathogens. However, like a scar after an injury, some survivors of severe infections develop complex post-infection fatigue syndromes with unknown aetiology. A prime example of these syndromes is the so-called Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) characterized by persistent or recurrent fatigue and post-exertion malaise accompanied by other debilitating symptoms. Until now ME/CFS has been primarily studied in cohort of patients from Europe, North America, and Australia. However, several studies conducted in the Tropics have recently reported ME/CFS-like symptoms in survivors of distinct viral outbreaks (e.g., Ebola, Dengue, Zika, and Chikungunya viruses). A similar observation was reported for infected health workers in the follow-up of the 2003-2004 SARS pandemic caused by the SARS-Coronavirus 1.

In this Research Topic, we aim to take the pulse of the current understanding of these complex post-infection fatigue syndromes, including ME/CFS, Gulf War Illness, and other related illnesses. We are particularly interested in providing a platform of discussion on the underlying pathophysiological mechanisms in order to assess the accuracy of current diagnostic tools and success of available treatments. The ultimate goal is to provide a possible estimation of the true burden of these symptoms across populations and their societal and economic impact.

We are inviting researchers across different disciplines of science to contribute with primary research papers, opinion papers, reviews, or systematic reviews related to epidemiology, pathophysiological mechanisms, immunity, diagnosis and treatment, and health economics of these complex post-infection syndromes, including ME/CFS. In particular, we invite critical reviews and discussions of the respective case definitions as a way to improve diagnosis and subsequent treatments. To obtain a broad view of this research topic, we are strongly encouraging primary research from endemic countries of different tropical pathogens - Ebola virus, Chikungunya virus, Dengue virus, and others - with the potential of causing ME/CFS-like symptoms.