Images of Blastocystis spp. stained using Hoechst stain (blue), FITC Annexin (V), and EthidiumHomodimer (III). (a) represents Blastocystis cells from subtype 3 and 2 (b) represents cells from subtype 1 (A) light microscopy images showing drug treated (0.0001 mg/ml) Blastocystis spp. (B) Blastocystis spp stained with Hoechst stain (blue) (C) Blastocystis spp stained with Annexin (V) (green) (D) Blastocystis spp stained with EthidiumHomodimer (III) (red). Annexin V labeled with fluorescein (FITC) identify apoptotic cells by binding to PS exposed on the outer membrane of Blastocystis spp. EthD-III is a highly positively charged nucleic acid probe, which is impermeant to live cells or apoptotic cells but stains late apoptotic-necrotic cells. (A: Apoptotic).