Hit-and-run Injury To The Brain: New Evidence On Chronic Fatigue Causation

Australian researchers have put the suggestion in this week's Journal of Infectious Diseases, which reveals new findings from the 'Dubbo Infection Outcomes Study'. Since 1999, a team led by UNSW Professor Andrew Lloyd have been tracking the long-term health of individuals infected with Epstein-Barr virus (EBV), Ross River virus (RRV) or Q fever infection. Their goal is to discover whether the post-infection fatigue syndrome that may affect up to 100,000 Australians is caused by the persistence of EBV, a weakened immune system, psychological vulnerability, or some combination of these.

Glandular fever -- sometimes called 'the kissing disease' -- is caused by Epstein-Barr virus (EBV). Transmitted via saliva, its acute symptoms include fever, sore throat, tiredness, and swollen lymph glands. Most patients recover within several weeks but one in ten young people will suffer prolonged symptoms, marked by fatigue. When these symptoms persist in disabling degree for six months or more, the illness may be diagnosed as chronic fatigue syndrome (CFS).

The researchers followed the course of illness among 39 people diagnosed with acute glandular fever. Eight patients developed a 'post-infective fatigue syndrome' lasting six months or longer, while the remaining 31 recovered uneventfully. Detailed studies of the activity of the Epstein-Barr virus in the blood and the immune response against the virus were conducted on blood samples collected from each individual over 12 months.

Commenting on the findings, Professor Lloyd says: "Our findings reveal that neither the virus nor an abnormal immune response explain the post-infective fatigue syndrome. We now suspect it's more like a hit and run injury to the brain.

"We believe that the parts of the brain that control perception of fatigue and pain get damaged during the acute infection phase of glandular fever. If you're still sick several weeks after infection, it seems that the symptoms aren't being driven by the activity of the virus in body, it's happening in the brain."

The research team comprising scientists from the University of New South Wales, the University of Sydney and the Queensland Institute of Medical Research plan to test their 'brain injury' hypothesis by doing neurological tests on the study participants.

About the Dubbo Infection Outcomes Study: this is a major prospective cohort study following individuals from the time of onset of documented infection with Epstein-Barr virus (the cause of glandular fever), Ross River virus (the mosquito-borne infection which causes rash and joint pain) and Q fever (an infection common in meatworkers and those exposed to livestock).

Research Paper:
'Prolonged illness after infectious mononucleosis is associated with altered immunity but not with increased viral load', The Journal of Infectious Diseases, vol. 193 (2006), pp 664-671. Authors: Barbara Cameron, Mandvi Bharadwaj, Jacqueline Burrows, Chrysa Fazou, Denis Wakefield, Ian Hickie, Rosemary French, Rajiv Khanna, Andrew Lloyd.

Funding:
The Dubbo Infection Outcomes Study is 82 per cent funded by the US Centers for Disease Control. It also receives funding from the National Health and Medical Research Council of Australia.