What is the morphology of Entamoeba histolytica?
Entamoeba histolytica [causes amoebic dysentery in man and primates] Parasite morphology: The trophozoites are 20-30 µm in diameter and contain a vesicular nucleus with a central endosome, peripheral chromatin and radial achromatic fibrils (imparting a ‘cart-wheel’ appearance).
What is the trophozoite stage of Entamoeba histolytica?
histolytica has a simple, two-stage life cycle, consisting of the infective cyst and colon-invasive trophozoite forms. E. histolytica infections occur when cysts are ingested through contaminated food or water. In the lower intestine trophozoites emerge from cysts (a process known as excystation).
What are the three morphological forms of Entamoeba histolytica?
Parasite occurs in three stages; trophozoite, precyst and cyst.
What shape and size is the cyst of Entamoeba histolytica?
Entamoeba histolytica and Entamoeba dispar are morphologically identical species. In bright-field microscopy, E. histolytica/E. dispar cysts are spherical and usually measure 12 to 15 µm (range may be 10 to 20 µm).
What is a trophozoite and how is it different from a cyst?
1. trophozoite – the motile vegetative stage; multiplies via binary fission; colonizes host. 2. cyst – the inactive, non-motile, infective stage; survives the environment due to the presence of a cyst wall.
What is the role of trophozoite?
The trophozoite absorbs nutrients from the intestinal lumen via pinocytosis and no specialized feeding organelles have been described. The trophic stage is also characterized by an asexual replication. Both nuclei divide at about the same time and cytokinesis restores the binucleated state.
What is the structure of trophozoite?
The ventral disc is the most distinctive structure of the trophozoite. It has been called the sucker cup, striated disc, and adhesive disc. Its shape is supported by a complex cytoskeleton of microtubules, microfilaments, and associated fibrous structures.
How do the trophozoites reproduce?
Giardia trophozoites multiply by splitting in two in a process called longitudinal binary fission, remaining in the small intestine where they can be free or attached to the inside lining of the small intestine.
What are the trophozoites of Entamoeba histolytica?
Trophozoites of Entamoeba histolytica resides in the mucosa and submucosa of the large intestine of man. It is the growing or feeding stage. The only form is present in the tissue. It usually appears only in diarrheic feces and survives only for few hours.
How many species of Entamoeba are there in humans?
There are 5 species of Entamoeba in human beings of which E. hartmanni and E. coli are non-pathogenic, and E. histolytica, E. gingivalis and E. polecki are pathogenic. The parasite is worldwide in distribution and more common in most countries of tropics and subtropics rather than temperate zones.
What is the clinical manifestation of amoeba histolytica infection?
Clinical manifestation: 1 Intestinal Amoebiasis#N#i. Asymptomatic infection: 90% of E. histolytica infection is mild or asymptomatic#N#ii. 2 Extra intestinal amoebiasis: More
What is the pathophysiology of Enterobacter histolytica?
Pathophysiology There are two forms E. histolytica can take: the cyst form, which can survive in the environment for a prolonged period, and the trophozoite stage, which is the active and invasive form.