Research Published on Post-Infective Fatigue

The high-profile medical journal BMJ (formerly the British Medical Journal) has published a study on post-infective fatigue from leading CFS researchers including Andrew Lloyd of the University of New South Wales and William Reeves and Suzanne Vernon of the CDC. The report details recent results from the Dubbo Infection Outcome Study, in this case examining the occurrence of post-infective fatigue at various intervals following infection of acute EBV (Epstein-Barr virus; glandular fever), Q fever (Coxiella burnetii) or RRV (Ross River virus; epidemic polyarthritis).

Investigators followed 253 individuals from the time of acute infection through periodic evaluations at six weeks, three months, six months and one year. At each phase a variety of symptoms were assessed and categorized into six domains: acute sickness, irritability, fatigue, musculoskeletal pain, mood disturbance and neurocognitive disturbance. At the six-month phase, patients were assessed using the international case definition for CFS.

Results of the study shed light on numerous aspects of post-infective fatigue syndrome (PIFS) and pointed to two significant findings. First, that prolonged illness characterized by disabling fatigue, musculo-skeletal pain, neurocognitive difficulties and mood disturbance was evident in a definitive subset of patients infected with EBV, Q fever and RRV. In fact, the PIFS phenotype occurred at a similar incidence regardless of the precipitating infection. Twelve percent of subjects experienced PIFS at six months, of whom all but one met the diagnostic criteria for CFS.

Second, the primary predictor of PIFS was the severity of the acute illness during infection rather than any demographic, psychological or microbiological factors.

Several things make this study different from previous investigations into post-infective fatigue. First, the application of the CFS case definition to designate incident cases in the post-infective setting provides strong evidence for a role of these infections in triggering CFS in certain instances. The findings confirm that CFS is a relatively common sequel of several different infections, now documented to include EBV, RRV and Q fever. Also, unlike other investigations, the cases identified in this study were required to have serological confirmation of EBV infection, continuity of the prolonged fatigue state and strict application of the CFS diagnostic criteria with exclusion of alternative medical or psychiatric disorders.

Researchers concluded that a relatively uniform PIFS persists in a significant minority of subjects for six months or more following clinical infection with several different viral and non-viral micro-organisms. As such, PIFS is a valid illness model for investigation of one pathophysiological pathway to CFS.

To access a copy of the report from BMJ, visit http://bmj.bmjjournals.com/cgi/content/abstract/bmj.38933.585764.AEv1?hrss=1.