Parasitology

Review Article

The ambiguous life of Dientamoeba fragilis: the need to investigate current hypotheses on transmission

JOEL L. N. BARRATTa1a2a3, JOHN HARKNESSa1a3, DEBORAH MARRIOTTa1a3, JOHN T. ELLISa2a3 and DAMIEN STARKa1a2 c1

a1 Division of Microbiology, SydPath, St Vincent's Hospital, Darlinghurst, Australia

a2 University of Technology Sydney, i3 Institute, Broadway, Australia

a3 University of Technology Sydney, Department of Medical and Molecular Biosciences, Broadway, Australia

SUMMARY

Dientamoeba fragilis is an inhabitant of the human bowel and is associated with gastrointestinal illness. Despite its discovery over a century ago, the details of Dientamoeba's life cycle are unclear and its mode of transmission is unknown. Several theories exist which attempt to explain how Dientamoeba may be transmitted. One theory suggests that animals are responsible for the transmission of Dientamoeba. However, reports of Dientamoeba in animals are sporadic and most are not supported by molecular evidence. Another theory suggests that Dientamoeba may be transmitted via the ova of a helminth. Given that the closest relative of Dientamoeba is transmitted via the ova of a helminth, this theory seems plausible. It has also been suggested that Dientamoeba could be transmitted directly between humans. This theory also seems plausible given that other relatives of Dientamoeba are transmitted in this way. Despite numerous investigations, Dientamoeba's mode of transmission remains unknown. This review discusses the strengths and weaknesses of theories relating to Dientamoeba's mode of transmission and, by doing so, indicates where gaps in current knowledge exist. Where information is lacking, suggestions are made as to how future research could improve our knowledge on the life cycle of Dientamoeba.

(Received September 15 2010)

(Revised October 11 2010)

(Revised November 22 2010)

(Accepted November 28 2010)

(Online publication February 24 2011)

Correspondence:

c1 Corresponding author: Department of Microbiology, St Vincent's Hospital, Victoria Street, Darlinghurst 2010, NSW, Australia. Tel: +61 2 8382 9196. Fax: +61 2 8382 2989. E-mail: dstark@stvincents.com.au

Metrics