Dientamoebiasis - Transmission

Transmission

Organisms similar to Dientamoeba fragilis are known to produce a cyst stage that is able to survive outside of the host and facilitate infection of new hosts. However, the exact manner in which Dientamoeba fragilis is transmitted is not yet known, as scientists have reported that the organism is unable to survive outside its human host for more than a few hours after excretion, and no cyst stage has been found.

Early theories of transmission suggested that Dientamoeba fragilis was unable to produce a cyst stage in infected humans, but some animal existed that in which it did produce a cyst stage, and this animal was responsible for spreading it. However, no such animal has ever been discovered. A later theory suggested the organism was transmitted by pinworms, which provided protection for the parasite outside of the host. Experimental ingestion of pinworm eggs established infection in two investigators. Numerous studies reported high rates of co-infection with helminths However recent study has failed to show any association between Dientamoeba fragilis infection and pinworm infection. Parasites similar to Dientamoeba fragilis are transmitted by consuming water or food contaminated with feces. The high rate (40%) of concomitant infection with other protazoa reported by at St. Vincent's Hospital, Sydney, Australia. supports the oral fecal route of transmission.