An interesting exchange on Twitter prompted this short post regarding a paper by Naess and colleagues* (full-text) on Giardia lamblia gastroenteritis and chronic fatigue syndrome (CFS). The tweets concerned another parasitic nasty called Toxomplasma gondii which has featured quite a bit on a sister blog with regards to its link to various behaviourally-defined conditions. I thought that T.gondii was a spine-tingling protozoa until someone posted about these other chaps and their brain-eating, behaviour-changing and belly exploding antics (pass the sauce, please).
Giardia lamblia is quite a special protozoa in terms of its survival, persistence and ability to link into quite a few other health complaints particularly of the gastrointestinal variety and specifically links to lactose intolerance. The current observations by Naess et al are interesting in that based on an examination of over 1200 patients with laboratory-confirmed giardiasis following a large community outbreak in Bergen, Norway, approximately 5% of cases (58/1262) were diagnosed with CFS as classified by the CDC criteria (see here for a related post on the trials and tribulations of diagnosing CFS/ME).
Even assuming a CFS prevalence of 1% previously noted in children (not adults) in the UK, the 5% figure seems high bearing in mind correlation is not necessarily causation. What can perhaps be ascertained from this latest study is that it might be a good idea to screen for giardiasis where active functional bowel issues are present alongside fatigue-related conditions and further research on any mechanism of parasitic infection linked to long-term fatigue might be advisable.
* Naess H. et al. Chronic fatigue syndrome after Giardia enteritis: clinical characteristics, disability and long-term sickness absence. BMC Gastroenterology. February 2012.