ENTAMEBA HISTOLYTICA 

Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates causing amoebiasis, E. histolytica is estimated to infect about 35-50 million people worldwide. E. histolytica infection is estimated to kill more than 55,000 people each year.


Morphological Forms of Entamoeba Histolytica

1) TROPHOZOITES 

  • Growing, feeding & invading form of E histolytica. 
  • Shape- not fixed due to constantly changing position. 
  • Size 18- 40µm.
  •  Cytoplasm is granular and may contain red cells and having a slow gliding movements due to pseudopodia.

 2) Pre cyst:

  • It is the intermediate stage between trophozoite and cyst
  • It is smaller in size; 10-20µ
  • It is round or slightly ovoid with blunt pseudopodium projecting from periphery
  • No RBC or food materials are found on its endoplasm.

3) Cyst:
  • Infective form of Entameba histolytica. 
  • Rounded shape surrounded by a highly refractile membrane the cyst wall. 
  • Size 10-20µm.
  •  In early stages cytoplasm contain glycogen vacuole & chromotoidal bodies with rounded end that disappear in final quadrinucleate cyst.
  • Non motile and divided by binary fission & develop into binucleate & quadrinucleate bodies.
LIFE CYCLE OF ENTAMEOBA HISTOLYTICA