MUC5AC and irritable bowel syndrome: The finding that Giardia can induce alterations to mucin glycosylation beyond the site of infection and that these alterations can persist after parasite clearance, is of particular interest in the context of post-infectious and extra-intestinal complications, such as post-infectious irritable bowel syndrome (IBS).10 IBS has been associated with intestinal barrier dysfunction,24 resulting in visceral pain and diarrhea.