Amoebae-Amoebae that infect human being are divided into:1-Intestinal amoebae. a-Commensals in man (non-pathogenic) as: -Entamoeba coli. -Entamoeba hartmanni. -Entamoeba gingivalis. -Endolimax nana. -Iodamoeba butschlii. b-Pathogenic to man: - Entamoeba histolytica.2-Free living amoebae (pathogenic): -Naegleria fowleri. -Acanthamoeba spp.

Entamoeba histolytica

-Morphology

Trophozoite

• cyst

PathogenesisThe invasiveness of the strain:1-phagocytic activity.2-production of cytolytic enzymes.3-production of cytotoxins (enterotoxins).4-resistance to the host's inflammatory response.5-contact-dependent cytolysis