GIardia infection associated with increased risk of IBS and fatigue

Being exposed to giardia, even if successfully treated, is associated with increase risk of irritable bowel syndrome and fatigue. The risk is 3-4 times increased according a new study from Norway (Gut 2011, Wensaas). It is well-recognized that IBS may be triggered by a previous gastrointestinal infection, the post-infectious form of IBS. Antibiotics and probiotics either separately or together have had favorable results in treating symptoms of IBS, especially the diarrhea predominant form (IBS-D). In my clinical experience with IBS type patient with elevated mast cells (mastocytic enterocolitis) fatigue is a common symptom. Giardia is a parasite that commonly elicits mast cell activation. It is not known what results in elevated mast cells in the intestinal tract but previous infection is suspected. The current study did not specifically look for elevated mast cells in intestinal biopsies of patients with IBS after exposure to giardia. This would be an interesting study to perform. Obtaining a history of prior giardia infection, screening for active giardia infection and looking for elevated mast cells in patients in IBS-D, especially with symptoms of fatigue is in my opinion reasonable.