Han-Yueh Kuo¹, Dung-Hung Chiang¹, Chien-Chun Wang¹, Te-Li Chen^1,2,3, Chang-Phone Fung³, Chih-Pei Lin⁴, Wen-Long Cho³, Cheng-Yi Liu¹
Sections of ¹Infectious Diseases and ²General Medicine, Department of Medicine, Taipei Veterans General Hospital, Taipei; ³Institute of Tropical Medicine, School of Medicine, National Yang-Ming University, Taipei; and ⁴Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan

Received: June 13, 2007      Revised: June 19, 2007       Accepted: July 27, 2007

Corresponding author: Dr. Te-Li Chen, Section of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, 201, Section 2, Shih-Pai Road, Taipei 11217, Taiwan. E-mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

Background and Purpose: Blastocystis hominis is an intestinal protozoan. The pathogenic role of this organism in human beings is still controversial and has varied among reports from different geographic areas. The purpose of this study was to determine the clinical significance of B. hominis in northern Taiwan.

Methods: A total of 100 patients who had a positive B. hominis stool examination during the period April to December of 2001 were retrospectively identified from Taipei Veterans General Hospital. The demographic and clinical characteristics of these patients were reviewed from the medical records.

Results: All of the patients were adults. Fifty nine patients had more than one underlying diseases, including malignancies. Twenty one patients presented with fever and 10 patients had gastrointestinal symptoms, including diarrhea and/or abdominal pain. However, all of the patients had other conditions that might have contributed to the clinical presentation, and they improved without specific treatment for B. hominis. Furthermore, there were no significant differences in clinical symptoms and white blood cell count between patients with malignancy or diabetes mellitus and those without. Six patients had hypereosinophilia that could not be attributed to other causes. Among 34 patients who had a further stool examination within one year, B. hominis was undetectable in 31 patients (91.2%), despite their having no specific antiprotozoal treatment.

Conclusions: The association of clinical symptoms and B. hominis could not be delineated from our study, even in immunocompromised patients. All of the patients improved without receiving any specific therapy. More studies from different areas are needed in order to delineate the clinical significance B. hominis.

Key words: Blastocystis hominis; Disease management; Risk factors; Signs and symptoms

J Microbiol Immunol Infect. 2008;41:222-226.