Evaluation of specific gravity of Giardia duodenalis and E. coli cysts

Abstract

Cysts of Giardia duodenalis and Entamoeba coli were observed as for flotability in sucrose solutions of different specific gravity, contained in counting-chambers of 0.17 mm height. The cysts that floated and those that sedimented were counted and then calculated the respective percentage. Flotability differences of the cysts of each species were not considerable. Solutions of specific gravity 1,200 kg/m³ made 88.49% of G. duodenalis cysts and 95.71% of E. coli cysts float. The greater values of flotability were associated to specific gravity 1,250 kg/m³ and were 89.15% and 98.59% for cysts of G. duodenalis and E. coli, respectively.