Trophozoites of Entamoeba histolytica with ingested erythrocytes 

• Trichrome stain.  The ingested erythrocytes appear as dark inclusions.  Erythrophagocytosis is the only characteristic that can be used to differentiate morphologically E. histolytica from the nonpathogenic E. dispar. 

• In these specimens, the parasite nuclei have the typical small, centrally located karyosome, and thin, uniform peripheral chromatin.  (E:  specimen contributed by the Texas Department of Health.)

Courtesy of the Division of Parasitic Diseases at the National Center for Infectious Diseases, Centers for Disease Control and Prevension (public domain)