ME/CFS stands for an illness known as either Myalgic Encephalomyelitis or Chronic Fatigue syndrome. It is sometimes also defined as CFIDS, (Chronic Fatigue and Immune Dysfunction Syndrome.) It is a chronic neurological illness effect approx $40 million worldwide. It it is extremely debilitating. Severe sufferers are blind, in severe pain, having seizures, sensitive to touch, sound, and light, unable to speak, paralysed, suffering severe mental and cognitive deficits, and symptoms of the flu. It is an underfunded illness with associated stigma because unless a sufferer is severely ill others cannot always see that the patient is ill because the illness can be invisible. Overdoing it mentally or physically will cause a relapse and the patient will spend days to years to recover. Unless they have a progressive illness from which they never recover. A full symptom list can be found here http://www.hfme.org/mesymptoms.htm
Triggers include trauma, infection , vaccination, pregnancy, and many more. Causes include infections, heavy metal or pesticide poisonings, and malnutrition.
The WPI stands for the Whittemore Peterson Institute, a charity in Nevada. http://www.wpinstitute.org/ They are funding research into ME/CFS and other neuroimmune illnesses like fibromyalgia, autism, and gulf war syndrome.