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Oh my aching gut: irritable bowel syndrome, Blastocystis, and asymptomatic infection

Kenneth F Boorom1*, Huw Smith2, Laila Nimri3, Eric Viscogliosi4, Gregory Spanakos5, Unaiza Parkar6, Lan-Hua Li7, Xiao-Nong Zhou8, Ülgen Z Ok9, Saovanee Leelayoova10 and Morris S Jones11

Author Affiliations

1 Blastocystis Research Foundation, 5060 SW Philomath Blvd, #202, Corvallis, OR 97333, USA

2 Scottish Parasite Diagnostic Laboratory, Stobhill Hospital, Glasgow, G21 3UW, UK

3 Department of Medical Laboratory Sciences, Jordan University of Science & Technology, Irbid, Jordan 22110 (currently at Center for Disease Control, Atlanta, GA, USA)

4 Unite' Inserm U547, Institut Pasteur, 1 Rue du Professeury Calmette, BP 245, 59019 Lille Cedex, France

5 Department of Parasitology, Entomology and Tropical Diseases, National School of Public Health, 196 Alexandras Ave, 11521 Athens, Greece

6 WHO Collaborating Centre for the Molecular Epidemiology of Parasitic Infections and the State Agricultural Biotechnology Centre, School of Veterinary and Biomedical Sciences, Murdoch University, South Street, Western Australia 6150, Australia

7 Department of Preventive Medicine, Weifang Medical University, 288 Shengli East Street, Shandong, Weifang, 261042, People's Republic of China

8 National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025, People's Republic of China

9 Department of Parasitology, Faculty of Medicine, Celal Bayar University, Manisa, Turkey

10 Department of Parasitology Phramongkutklao College of Medicine, Ratchathewi, Bangkok 10400, Thailand

11 Clinical Investigation Facility, David Grant USAF Medical Center, 101 Bodin Circle, Travis AFB, CA 94535, USA

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Parasites & Vectors 2008, 1:40  doi:10.1186/1756-3305-1-40

Published: 21 October 2008


Blastocystis is a prevalent enteric protozoan that infects a variety of vertebrates. Infection with Blastocystis in humans has been associated with abdominal pain, diarrhea, constipation, fatigue, skin rash, and other symptoms. Researchers using different methods and examining different patient groups have reported asymptomatic infection, acute symptomatic infection, and chronic symptomatic infection. The variation in accounts has lead to disagreements concerning the role of Blastocystis in human disease, and the importance of treating it. A better understanding of the number of species of Blastocystis that can infect humans, along with realization of the limitations of the existing clinical laboratory diagnostic techniques may account for much of the disagreement. The possibility that disagreement was caused by the emergence of particular pathogenic variants of Blastocystis is discussed, along with the potential role of Blastocystis infection in irritable bowel syndrome (IBS). Findings are discussed concerning the role of protease-activated receptor-2 in enteric disease which may account for the presence of abdominal pain and diffuse symptoms in Blastocystis infection, even in the absence of fever and endoscopic findings. The availability of better diagnostic techniques and treatments for Blastocystis infection may be of value in understanding chronic gastrointestinal illness of unknown etiology.