Dauer

Dauer is the German word for persistence or long-lived.

Dauer larva
An alternative developmental stage known as dauer or dauer state has been found to in nematode worms, particularly Caenorhabditis elegans, whereby the larva goes into a type of stasis as a result of harsh environmental conditions. The dauer worms stop feeding, and significantly reduce their movement, and have been reported to reversibly alter some of their sensory neurons.

Used in relation to Chronic Fatigue Syndrome
Dauer, or hibernation, was used to explain Chronic Fatigue Syndrome in the paper Metabolic features of chronic fatigue syndrome; CFS was described as a "hypometabolic response to environmental stress similar to dauer".

Letter: Reply to Vogt et at.
A letter by Vogt et at. (2016) challenged the conclusions drawn, stating that psychosocial or psychological causes could not be ruled and challenging the validity of the diagnosis of chronic fatigue syndrome. Naviaux et al. replied that "... chemical details of the metabolic findings in ME/CFS led directly to a survey of other hypometabolic syndromes like dauer, diapause, torpor, hibernation, and caloric restriction. It was the detailed nature and specific pattern of abnormalities affecting six pathways (sphingolipids, phospholipids, purines, cholesterol, polyamines, and redox metabolism), and not the over 50 other biochemical pathways interrogated, that focused our attention on dauer. In dauer, there is a reprioritization of sensory processing that is metabolically controlled (9). This situation bears similarities to ME/CFS."

Letter: Reply to Roerink et al.
A letter from Roerink et al. raised questions and concerns about the lack of controls for exercise, diet and drug use, which they stated may have affected the results. Naviaux and Gordon replied that the initial phase was done only with ambulatory CFS patients (i.e., able to walk/mobile), and clarified and corrected points raised about statistical methods used.

Open Medicine Foundation
After the publication of the article, Dr Ron Davis invited Robert Naviaux to join the OMF Scientific Advisory Board.