Brief Summary

Trichomonads, such as Pentatrichomonas hominis, are obligate protozoan symbionts found in vertebrates and (with exceptions) are considered to be generally non-pathogenic. They bear multiple anterior flagella and a single recurrent (i.e., posteriorly directed) flagellum that functions as an undulating membrane. Pentatrichomonas hominis inhabits the large intestine of a number of mammalian hosts, including cats, dogs, non-human primates, and pigs. Opportunistic overgrowth of P. hominis can cause disease, typically involving diarrhea. Trophozoites of P. hominis reproduce by binary fission and undergo direct host-to-host transmission without formation of environmentally stable cysts. (Kim et al. 2010)

Pentatrichomonas hominis is a trichomonad flagellate with a worldwide distribution. Only trophozoites are shed in feces as there is no known cyst stage for this species. Infection occurs after the ingestion of trophozoites in fecally-contaminated food or water or on fomites (i.e., other non-living objects or substances that can transmit them). These organisms reside in the large intestine, where they are regarded as commensals (i.e., benefiting from but not harming their host) and are not known to cause disease in humans. Centers for Disease Control Parasites and Health website