Commensal

• Commensal amoebae


  Harmless amoebae that may be mistaken for pathogenic Entamoeba histolytica
• Significance of identifying commensal amoebae


  • Administration of treatment may do more harm than good to the patient as the patient may have adverse reactions to the drug
  • Findings of commensal amoebae is an indication of fecal contamination of food or water
• Entamoeba dispar & Entamoeba moshkovskii


  Similar morphology with Entamoeba histolytica but different DNA and ribosomal RNA, differentiated only by PCR, ELISA, or isoenzyme analysis
• Entamoeba hartmanni


  Cytoplasm and nucleus is the same with Entamoeba histolytica EXCEPT for the absence of ingested RBS, smaller than Entamoeba histolytica
• Entamoeba coli


  Cosmopolitan in distribution, more common than other human amoebae
• Staining


  • Direct fecal smear, unstained (saline) – for the demonstration of motility
  • Stain – demonstrates granular part (endoplasm) and refractile part (ectoplasm)
  • Engulfed RBC is a diagnostic characteristic – if RBC is present, then it is E. histolytica
• Entamoeba polecki & Entamoeba chattoni

  Parasite found in the intestines of pigs and monkeys, rarely affects humans, morphologically similar
• Endolimax nana vs Iodamoeba butschlii


  E. nana – "clean" nucleoplasm, I. butschlii – small chromatin granules at periphery of nucleoplasm
• Entamoeba gingivalis


  Habitat: Mouth (surface of gum, teeth, gum pockets, tonsillar crypts), Transmission: Kissing, droplet spray, sharing utensils, Trophozoite: Moves quickly and with numerous blunt pseudopodia, Has food vacuoles containing cellular debris and bacteria, NO cystic stage
• Diagnosis


  Demonstration of typical trophozoite and/or cyst, Stool, Swab between gums and teeth: E. gingivalis
• Treatment – not necessary
• Prevention and Control


  • Proper disposal of human waste
  • Good personal hygiene