Entamoeba histolytica amoebic parasite

This iodine-stained photomicrograph revealed ultrastructural morphology exhibited by a binucleated cyst of an Entamoeba histolytica parasitic amoeba in a concentrated wet mount. Notice the chromatoid body with blunt, rounded ends, and only two nuclei are visible in this focal plane. Mature Entamoeba histolytica cysts have 4 nuclei that characteristically have centrally-located karyosomes and fine, uniformly distributed peripheral chromatin. Cysts usually measure 12 to 15 µm. Image courtesy CDC/Dr. Mae Melvin, 1977. (Photo by Smith Collection/Gado/Getty Images).