In 1918, Jepps and Dobell1 described the intestinal parasite, Dientamoeba fragilis, and suggested the name because of the morphology and characteristics. They give credit to Wenyon for first observing it in 1909, but the observation was not published. Since their paper appeared, about thirty-seven cases have been reported. Apparently most, if not all, of these occurred in adults.
Dientamoeba fragilis is described as a small ameba varying from 3.5 to 12 microns in diameter. According to Jepps and Dobell and to most of the other observers, it is normally binucleate in about 80 per cent of the individual organisms. Kudo,2 in 1926, however, in studying the organism in a single case, found that approximately only 12 per cent were binucleated. When not moving, they appear in moist preparations as small, rounded, granular bodies. During locomotion they protrude leaflike, hyaline pseudopodia with irregular margins which gives rise to a
GITTINGS JC, WALTZ AD. DIENTAMOEBA FRAGILIS. Am J Dis Child. 1927;34(4):542-546. doi:10.1001/archpedi.1927.04130220020003