Clinical significance of Blastocystis hominis: experience from a medical center in northern Taiwan

J Microbiol Immunol Infect. 2008 Jun;41(3):222-6.


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.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Blastocystis Infections / epidemiology*
  • Blastocystis Infections / parasitology
  • Blastocystis Infections / physiopathology*
  • Blastocystis hominis / isolation & purification*
  • Feces / parasitology
  • Female
  • Hospitals
  • Humans
  • Male
  • Middle Aged
  • Retrospective Studies
  • Taiwan