This is an interesting and useful short research report from doctors in Singapore who have looked at the incidence of post-infectious fatigue syndrome in people recovering from a tropical infection known as dengue fever.
The research involved a cohort of 127 patients (71 male; 56 female; mean age 36) with serologically confirmed dengue infection who were admitted to hospital in Singapore during a dengue outbreak in October – November 2005.
Significant post-infectious fatigue was observed in approximately 25% of the hospitalised patients. Risk factors for the development of fatigue included older age, female sex, and the presence of chills.
The study adds further confirmation to the fact that a wide range of infections, predominantly viral, can trigger an ME/CFS-like illness. It also adds some support to the disease model involving immune dysfunction (including excessive immune chemical/cytokine production), hypothalamic-pituitary-adrenal axis dysfunction, and autonomic nervous system dysfunction. The results also help to confirm that debilitating and prolonged post-infectious fatigue is not simply a ‘Western disease'.
Post-infectious fatigue syndrome in dengue infection
Journal of Clinical Virology, Volume 38, Issue 1, January 2007, Pages 1-6
Raymond C.S. Seet, Amy M.L. Quek and Erle C.H. Lim
NOTE ON DENGUE FEVER AND PVFS/ME/CFS
Dengue fever is caused by an arbovirus infection that is transmitted to humans by mosquito bites. It occurs throughout the tropics and sub tropics – South East Asia in particular. Initial symptoms occur abruptly – often about 5 – 8 days after a bite. These include intense muscle and joint pain (‘break-bone fever'), severe headache, sore throat, fever, and a blanching rash, and are normally over within a week. A much more severe form called dengue haemorrhagic fever, involving internal bleeding and shock, can also occur. Dengue encephalitis and encephalopathy with neurological sequele sometimes occurs. Subclinical infections also occur. There is no specific antiviral therapy or vaccine currently available.
Overseas travellers and backpackers returning from more exotic locations form a sub-group of patients with post-infectious fatigue syndromes that may then progress into an ME/CFS-like illness. Although dengue fever is already well recognised to be a cause of prolonged debility this is the first research paper to look at the development of a more specific post-infectious fatigue syndrome. A number of other tropical infections are also known to cause post-infectious fatigue syndromes and this highlights the importance of including questions about overseas travel when a diagnosis of ME/CFS is being considered.
The fact that a high percentage of people with dengue fever experience significant post-infectious fatigue indicates that this infection could be used as a model to study and compare some of the endocrine and immunological abnormalities that have been found in ME/CFS with dengue patients who do or do not develop post-infection fatigue.
Dr Charles Shepherd
Hon Medical Adviser, The ME Association