Cysts of Entamoeba histolytica/dispar
G H   I   J   K

 

  • Cysts of Entamoeba histolytica/dispar.  Line drawing (G), wet mounts stained with iodine (H, I) and permanent preparations stained with trichrome (J, K).
  • The cysts are usually spherical and often have a halo (H, I). 
  • Mature cysts have 4 nuclei. The cyst in H appears uninucleate while in I, J and K 2 to 3 nuclei are visible in the focal plane (the fourth nucleus is coming into focus in J). 
  • The nuclei have characteristically centrally located karyosomes, and fine, uniformly distributed peripheral chromatin. 
  • The cysts in I, J and K contain chromatoid bodies with the one in J being particularly well demonstrated, with typically blunted ends.  Entamoeba histolytica cysts usually measure 12 to 15 µm
  • Courtesy of the Division of Parasitic Diseases at the National Center for Infectious Diseases, Centers for Disease Control and Prevension (public domain)
  • http://www.dpd.cdc.gov/DPDx/HTML/Amebiasis.htm