Table 7 outlines some key features in differentiating the cysts of the flagellates.
Table 7. Differentiating Giardia and Dientamoeba Cysts from those of the Commensal Flagellates.Organism | Image | Nuclei # | Other Features |
Giardia duodenalis Usually oval (can be round) Usual size: 11-14 x 7-10 μm | (27) | 4 | Deep staining median bodies lie across longitudinal fibers Shrinkage gives a halo effect (arrow) |
Dientamoeba fragilis Oval to round 5-8 μm | Cysts exist but are very rarely seen, and difficult to identify. | 2 | Can show shrinkage |
Chilomastix mesnili Lemon or pear shaped with hyaline knob Usually 7-9 x 4-6 μm | (28) | 1 | Cytostome with supporting fibrils |
Pentatrichomonas hominis | No cysts | | |