Practical No.
Study of developmental stages and pathogenicity of Entamoeba histolytica
Aim: Study of developmental stages and pathogenicity of Entamoeba histolytica
Introduction:
Entamoeba histolytica is an endoparasite that infects humans and causes
amoebiasis. Entamoeba histolytica is a protozoan parasite. Predominantly
infecting humans and other primates causing amoebiasis, E. histolytica is
estimated to infect about 35-50 million people worldwide.
The active (trophozoite) stage exists only in the host and in fresh loose
faeces. Cysts survive outside the host, in water, in soils and on foods especially
under moist conditions. It is transmitted through fecal-oral route, so it is more
common in countries with poor sanitation. Entamoeba histolytica has a relatively
simple life cycle with two primary stages. The infectious cyst stage, which is
environmentally resistant and transmitted through fecal-oral contamination. The
invasive trophozoite stage, responsible for causing disease by actively
multiplying and invading the intestinal mucosa.
Trophozoite Stage:
Structure: A single-nucleated, actively dividing, motile cell with
pseudopodia for movement.
Pathogenesis:
• Intestinal Invasion: Trophozoites adhere to the intestinal mucosa, secrete
proteolytic enzymes to disrupt the epithelial barrier, and invade the
intestinal wall.
• Tissue Destruction: Once inside the tissue, trophozoites can directly kill
host cells by phagocytosis and release cytotoxic substances, leading to
inflammation and ulceration.
Study of developmental stages and pathogenicity of Entamoeba histolytica
Aim: Study of developmental stages and pathogenicity of Entamoeba histolytica
Introduction:
Entamoeba histolytica is an endoparasite that infects humans and causes
amoebiasis. Entamoeba histolytica is a protozoan parasite. Predominantly
infecting humans and other primates causing amoebiasis, E. histolytica is
estimated to infect about 35-50 million people worldwide.
The active (trophozoite) stage exists only in the host and in fresh loose
faeces. Cysts survive outside the host, in water, in soils and on foods especially
under moist conditions. It is transmitted through fecal-oral route, so it is more
common in countries with poor sanitation. Entamoeba histolytica has a relatively
simple life cycle with two primary stages. The infectious cyst stage, which is
environmentally resistant and transmitted through fecal-oral contamination. The
invasive trophozoite stage, responsible for causing disease by actively
multiplying and invading the intestinal mucosa.
Trophozoite Stage:
Structure: A single-nucleated, actively dividing, motile cell with
pseudopodia for movement.
Pathogenesis:
• Intestinal Invasion: Trophozoites adhere to the intestinal mucosa, secrete
proteolytic enzymes to disrupt the epithelial barrier, and invade the
intestinal wall.
• Tissue Destruction: Once inside the tissue, trophozoites can directly kill
host cells by phagocytosis and release cytotoxic substances, leading to
inflammation and ulceration.
