Review
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World J Gastroenterol. Dec 21, 2013; 19(47): 8974-8985
Published online Dec 21, 2013. doi: 10.3748/wjg.v19.i47.8974
Extra-intestinal and long term consequences of Giardia duodenalis infections
Marie CM Halliez, André G Buret
Marie CM Halliez, André G Buret, Department of Biological Sciences, Inflammation Research Network, University of Calgary, Calgary, Alberta, AB T2N 1N4, Canada
Marie CM Halliez, Parasitology Department, Rouen University Hospital & EA 3800, Institute for Biomedical & Research, University of Rouen, Rouen, 76183, France
Author contributions: Halliez MCM and Buret AG wrote the paper.
Supported by Grants from the Natural Sciences and Engineering Research Council of Canada (individual operating and CREATE), the France-Canada Research Fund; and the “Ministère de l’enseignement supérieur et de la recherche”, French Ministry of Secondary Education and Research
Correspondence to: André G Buret, PhD, Professor, Department of Biological Sciences, Inflammation Research Network, University of Calgary, 2500 University Drive NW, Calgary, Alberta, AB T2N 1N4, Canada. aburet@ucalgary.ca
Telephone: +1-403-2202817 Fax: +1-403-2899311
Received: July 11, 2013
Revised: August 29, 2013
Accepted: September 16, 2013
Published online: December 21, 2013
Abstract

Giardiasis is the most common waterborne parasitic infection of the human intestine worldwide. The etiological agent, Giardia duodenalis (syn. G. intestinalis, G. lamblia), is a flagellated, binucleated protozoan parasite which infects a wide array of mammalian hosts. Human giardiasis is a true cosmopolitan pathogen, with highest prevalence in developing countries. Giardiasis can present with a broad range of clinical manifestations from asymptomatic, to acute or chronic diarrheal disease associated with abdominal pain and nausea. Most infections are self-limiting, although re-infection and chronic infection can occur. Recent evidence indicating that Giardia may cause chronic post-infectious gastrointestinal complications have made it a topic of intense research. The causes of the post-infectious clinical manifestations due to Giardia, even after complete elimination of the parasite, remain obscure. This review offers a state-of-the-art discussion on the long-term consequences of Giardia infections, from extra-intestinal manifestations, growth and cognitive deficiencies, to post-infectious irritable bowel syndrome. The discussion also sheds light on some of the novel mechanisms recently implicated in the production of these post-infectious manifestations.

Keywords: Giardiasis, Inflammatory disorders, Extra-intestinal manifestations of enteritis, Failure to thrive, Post-infectious irritable bowel syndrome

Core tip: This review offers a state-of-the-art discussion on the long-term consequences of Giardia infections, the most common waterborne parasitic infection of the human intestine worldwide, from extra-intestinal manifestations, growth and cognitive deficiencies, to post-infectious irritable bowel syndrome. The discussion also sheds light on some of the novel mechanisms recently implicated in the production of these post-infectious manifestations.