DPDx is an education resource designed for health professionals and laboratory scientists. For an overview including prevention and control visit http://www.cdc.gov/parasites/nonpathprotozoa/index.html.
Chilomastix mesnili, a nonpathogenic flagellate.
The cyst stage is resistant to environmental pressures and is responsible for transmission of Chilomastix. Both cysts and trophozoites can be found in the feces (diagnostic stages) . Infection occurs by the ingestion of cysts in contaminated water, food, or by the fecal-oral route (hands or fomites) . In the large (and possibly small) intestine, excystation releases trophozoites. Chilomastix resides in the cecum and/or colon; it is generally considered a commensal whose contribution to pathogenesis is uncertain. Animals may serve as a reservoir for Chilomastix.
Chilomastix mesnili is considered nonpathogenic. The presence of cysts and/or trophozoites in stool specimens can however be an indicator of fecal contamination of a food or water source, and thus does not rule-out other parasitic infections.