Authors

Discussion

Dientamoeba fragilis is an enteric protozoan parasite commonly observed in human stool. Despite numerous clinical case reports associating D. fragilis with human diarrhoea, universal acceptance of this parasite as a pathogen  has not occurred. Central to the argument is the evaluation of real time PCR assays for the detection of D. fragilis in stool. In this study, three published PCR assays (hereafter called Verweij 2007, Caccio 2012, and EasyScreen^TM Enteric Protozoan Detection Kit (Genetic Signatures, Australia) were evaluated for sensitivity (using known numbers of cultured trophozoites spiked into a fecal sample) and specificity to closely related parasite taxa. All three assays yielded similar levels of sensitivity of about five trophozoites. The first two PCR methods demonstrated cross reactivity to other trichomonads limiting their usefulness for surveying animal samples. The third assay (Genetic Signatures) exhibited excellent specificity, although a low level cross-reactivity to Pentatrichomonas hominis was distinquished from   D. fragilis by melt curve analysis. The utility of the Easyscreen kit is shown by a survey of 400 animals, where we extend the host range of D. fragilis to a dog and a cat.