Chilomastix mesnili (Nonpathogen)
This organism belongs to the flagellates, is a nonpathogen, and causes no disease. Both the trophozoite (usual size, 6-24 µm long and 4-8 µm wide) and cyst forms (usual size, 6-10 µm long and 4-6 µm wide) can be found in clinical specimens.
Cyst in iodine
Cyst, permanent stain
Intestine, organisms passed in feces
Fecal-oral transmission via cyst form; contaminated food and water
Worldwide, primarily human-to-human transmission
Intestinal: Ova and Parasite examination (concentration, permanent stained smear)
Trophozoite: Pear shaped, 1 nucleus and distinct oral groove (cytostome); flagella are rarely seen without special stains.
Cyst: Pear or lemon shaped, will contain 1 nucleus; the cytostomal fibril is curved and is called the “shepherd’s Crook”.
Chilomastix mesnili (indicate trophozoites and/or cysts)
Improved hygiene, adequate disposal of fecal waste, adequate washing of contaminated fruits and vegetables
Small organisms can mimic other small protozoa.