Two-step gating strategy without the use of antibody staining.

(A) Pure population of C. parvum oocysts (positive control). (B) Sample from uninfected mouse intestine (negative control). (A and B) Plots from left to right: ungated sample SSC-A versus FSC-A, PerCP emission histogram of Oocyst gate, FSC-H versus PerCP including recommended PerCP gate. Representative sample from intestine (C) and from stool (D) of an infected mouse; and from stool of an uninfected mouse (E). (C, D and E) Plots from left to right: ungated sample SSC-A versus FSC-A, FSC-H versus PerCP including gate determined by positive control, overlay of PerCP- events corresponding to oocysts from the PerCP gate in blue and PerCP+ events corresponding to debris and beads in red. PerCP- events from the Oocyst gate are oocysts and PerCP+ events from the Oocyst gate are debris.