Entamoeba histolytica is a parasitic protozoan responsible for the disease amoebic dysentry. Entamoeba histolytica life cycle : There are two forms - 1. cyst : non-mobile form 2. trophozoit : Mobile form A.Cyst entry : Injection of food or water contaminated with Entamoeba histolytica cyst will move through the mouth down the oesophagus into the stomach. Cysts are resistant to gastric environment and passes through the stomach. B.Excystation : Each cyst can divide and produce 8 trophozoits the mobile form of Entamoeba histolytica in the small intestine. C.Multiplication : The trophozoites will then move to colon of large intestine then multiply and colonizes. Entamoeba can cause 2 types of infection : 1. non-invasive: 90% 2. invasive : 10% 1. Non-invasive : Trophozoits remain on the surface of mucus layer of colonic epithelium and multiplies by binary fission. This non-virulent form feeds on bacteria and detritus in lumen. D. Encystation : The trophozoites wil