Dientamoeba fragilis, a neglected cause of diarrhea, successfully treated with secnidazole

Clin Microbiol Infect. 2003 Feb;9(2):110-3. doi: 10.1046/j.1469-0691.2003.00504.x.


Objective: To evaluate the pathogenicity of Dientamoeba fragilis by comparing it with Giardia lamblia and to investigate the effect of a single dose of secnidazole in dientamoebiasis.

Methods: Stool samples of 400 patients, admitted to the Department of Parasitology, Celal Bayar University, were examined by direct wet mount, formalin-ethyl acetate concentration and trichrome staining methods on three consecutive days. All cases positive for D. fragilis were treated with a single dose of secnidazole, 30 mg/kg for children, and 2 g for adults. On the seventh and fourteenth days, at the end of the treatment, stool samples were examined by the same methods, and clinical symptoms were again evaluated.

Results: D. fragilis and G. lamblia were detected in 35 (8.8%) and 34 (8.5%) cases, respectively. The most frequent symptoms were found to be abdominal pain and diarrhea in both infections. D. fragilis was eradicated in 34 (97.1%) patients with a single dose of secnidazole, but a second dose was necessary in one patient. Clinical symptoms disappeared in 27 (77.1%) and decreased in eight (22.9%) cases, after eradication.

Conclusions: These data suggested that D. fragilis is as prevalent and pathogenic as G. lamblia, and secnidazole seems to be highly effective in achieving parasitologic and clinical cure. To our knowledge, this is the first report of secnidazole being used in the treatment of dientamoebiasis.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Antiprotozoal Agents / administration & dosage
  • Antiprotozoal Agents / therapeutic use*
  • Child
  • Child, Preschool
  • Diarrhea / drug therapy*
  • Diarrhea / microbiology*
  • Dientamoeba / pathogenicity*
  • Dientamoebiasis / drug therapy*
  • Feces / parasitology
  • Giardia lamblia / pathogenicity
  • Giardiasis / drug therapy
  • Humans
  • Metronidazole / administration & dosage
  • Metronidazole / analogs & derivatives*
  • Metronidazole / therapeutic use*
  • Middle Aged


  • Antiprotozoal Agents
  • Metronidazole
  • secnidazole