Transmission of Dientamoeba fragilis: pinworm or cysts?
Recently, conflicting evidence has been published on the mode of transmission of the trichomonad Dientamoeba fragilis. Detection of D. fragilis DNA inside Enterobius vermicularis eggs agrees with the prediction of Dobell in 1940 that the eggs of a nematode act as a vector for transmission. However, the identification of a cyst stage of D. fragilis in the stool of rodents infected with a human isolate has also been reported, and this implies a life cycle similar to those of most other intestinal protistan parasites. Herein we discuss the recent data, identify gaps in the experimental evidence, and propose a method for determining which view of the life cycle of this organism is correct.
Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
C Graham
CG
Clark
Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
Dennis
D
Röser
Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark. Electronic address: run@ssi.dk.
C Rune
CR
Stensvold
D000818:Animals; D004029:Dientamoeba / Q000469:parasitology*; D004030:Dientamoebiasis / Q000635:transmission*; D004199:Disease Vectors; D004757:Enterobius / Q000469:parasitology*; D005243:Feces / Q000469:parasitology; D006801:Humans; D008018:Life Cycle Stages / Q000502:physiology; D012377:Rodentia / Q000469:parasitology
Dientamoeba; Enterobius; cyst; life cycle; transmission; trichomonad