Viral onset hypothesis

Many myalgic encephalomyelitis and chronic fatigue syndrome patients report falling ill after an acute viral infection.

Many different viruses have been researched as possible etiological agents.

Disease onset
Some think there is a single, novel viral agent as yet undiscovered.

Others think many different viruses can initiate the disease. Viruses implicated in disease onset include herpesviruses such as Epstein barr virus or HHV-6, enteroviruses such as coxsackie or even the flu. However, no consistent markers found in viral serologies measuring antibody titers to 13 viruses.

Pathophysiology
For patients who trace their illness to a viral onset, there are several hypotheses for how the viral trigger initiates and perpetuates the disease.

Chronic infection
Some think that there may be a low grade, chronic infection whereby the initial virus continues to provoke an immune response, especially in key areas such as the gastrointestinal tract, muscle, and the brain, brainstem, and spinal cord.

Autoimmune disease
Some think that symptoms are caused by an inflammatory process that is triggered by an initial infection and continues even after the initial virus is no longer replicating. It is possible that ME/CFS is an autoimmune response that can be triggered by many different infections.

Viral reactivation
Still others think that an immune deficiency allows otherwise common or benign viruses to replicate.

Dysbiosis
Viral infection triggers dysbiosis leading to alterations in the immune system and gut-brain axis and causing the symptoms of the disease.

Outbreaks
There have been dozens of reported clusters and outbreaks of ME, which all suggest a role of either a communicable pathogen or in some cases, a toxic agent.