A number of triggers appears to set it off, including:
- a wide range of viral infections. This has been confirmed by lab tests showing that, in half of patients, the 2-5A synthetase/ribonuclease L (Rnase) pathway is not functioning properly, as seen with viral disorders. These cellular fragments wreak havoc inside cells, and can also block thyroid receptors. Despite normal test results on routine screening, thyroid cells may not be functioning.
- one or more environmental, biological or chemical triggers. These may be vaccinations, anaesthetics, exposures to environmental pollutants, chemicals or heavy metals, a physical trauma such as a car accident, a fall or surgery or, in rare cases, a blood transfusion.
- stress. MRI (magnetic resonance imaging) scans show areas of 'high signal' in the white matter of the central nervous system, demonstrating a pathology of the CNS and immune system not unlike that seen in patients with AIDS.
Those who do take ME seriously divide into two camps: the virus hunters who blame a persistent virus and not the immune system which allowed the virus access, and those who see ME as activated by trigger factors, one of which may be a virus, but only as a co-factor with other triggers leading to weakened immunity.
The recent discovery of the post-polio syndrome progressive muscular weakness and fatigue, and persistent viruses all occurring some 25 or 30 years after recovery from paralytic polio, gives weight to the argument of a connection between polio and ME. Furthermore, from 1955, when general poliomyelitis immunization was introduced, the incidence of paralytic poliomyelitis fell but that of ME continued, in a changed form; it now rarely causes paralysis.
Other possible causes to consider include:
- Candidiasis, an overgrowth of yeast organisms in the intestines.
- Magnesium, selenium and other mineral deficiencies.
- Allergies and sensitivities to foods, pollutants, animal products, plant products and chemicals.
- Depression as a result of the debilitating nature of the illness, not a direct cause of the condition.
- Depletion of vitamin B12 levels.