ABSTRACT
In 1984-87, an outbreak of debilitating fatigue was reported by two physicians in the private practice of internal medicine in Incline Village, Nevada. Follow-up questionnaires were sent in 1995 to the 259 patients in this outbreak. The results were analyzed to determine how many patients met the latest Centers for Disease Control and Prevention (CDC) case definition for Chronic Fatigue Syndrome (CFS), Id-iopathic Chronic Fatigue (ICF), or Prolonged Fatigue (PF). Data were analyzed separately for those living in the Lake Tahoe area and those referred from other locales. Of those returning questionnaires (123/259), 41% met the CDC case definition for CFS, 56% met the criteria for inclusion in the subgroup ICF, and 3% experienced PF. In the population-based Lake Tahoe group, symptomatic women were more likely to have CFS than ICF whereas symptomatic men were likely to fit ICF criteria. Also in this group, full recovery was reported more often among Lake Tahoe participants classified as having ICF (43%) than participants classified as having CFS (15%).