Entamoeba histolytica

• • Infective stage: Mature quadrinucleate cyst
• • Diagnostic stage: Trophozoite, cyst
• • Mode of transmission: Ingestion of food and water contaminated with the cysts
• • Disease: Intestinal amebiasis, amebic colitis, amebic dysentery, extraintestinal amebiasis

  • Flask-shaped ulcer

  • Most common extraintestinal complication of amebiasis: hepatic involvement (Thick chocolate brown pus/ anchovy sauce pus)

  • CNS involvement: Secondary Amebic Meningoencephalitis
• • Diagnosis: Wet preparation, permanent stained smear, culture (TYI-S-33), Serological tests

  = LIFE CYCLE of E. histolytica

  A) Cyst and Trophozoite

  B) Mature Cyst

  C) Excystation

  D) Trophozoites

  
• Entamoeba histolytica cyst

  + Spherical to round

  + Coffin-shaped chromatoid bars

  + Central karyosome

  + Fine and evenly distributed chromatin

  + May contain one to four nuclei.
• Entamoeba histolytica Cyst

  A) Cytoplasm

  B) Central Karyosome

  C) Cyst Wall

  D) Chromatoid Bar

  E) Even Peripheral Chromatin

  
• Entamoeba histolytica trophozoite

  + Rapid, unidirectional, progressive movement

  + Single nucleus with small central karyosome

  + Presence of ingested RBCs in the cytoplasm is considered diagnostic of Entamoeba histolytica
• Entamoeba histolytica trophozoite

  A) Cytoplasm

  B) Ingested RBC

  C) Central Karyosome

  D) Even Peripheral Chromatin

  E) Pseudopod