Fig. 4.

Electron micrographs show some of the parasitic stages within the brush borders of the affected intestinal mucosa. A; thin-walled sporulated oocysts (black arrow), about to release their contents to invade another cell. Notice the affected microvilli within the affected area (red arrows) and the interrupted tight junction (blue arrow). B; larger view shows the invasion process with a nearby developed trophozoite with an evident nucleolus. C; another parasitic stage with apparent internal and external features shows attachment zone (A.Z), a dense band subjacent to the parasite-absorptive cell interface (AC), starting feeder organelles (F.O), pellicle of the parasite (P.P), outer and inner envelops (O.E & I.E), forming endoplasmic reticulum (*) plus Electron-lucent appearance of the rhoptries (R) (Scale bar; 500 nm in A and 100 nm in B, C &D). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)