Entamoeba histolytica

Amoebic dysentryDr. Tjatur Winarsanto SpPDRST CiremaiCirebonIntroduction 1. The only pathogenic amoeba among all of the intestinal amoebae 2. Infecting perhaps 10% of the world's population. 3. Lead to invasive amoebiasis.

Entamoeba histolyticaEntamoeba disparMajor pathogenworld-wide distribution (10%)5% in some developed countries100 deaths in Chicago 1930Trophozoite & Cystoral-faecal transmissionTrophozoite (active form)(1) Size: 10-40 micrometers in diameter, some are above 60 micrometers.(2) Pseudopodium(ectopalsmic protrusion): A. broad or finger-like in form B. thrust out quickly C. firstly, formed with ectoplasm, secondly, endoplasm flows slowly into it. D. motility is progressive and directional.

Trophozoite (active form)(3) Endoplasm: red blood cells may be found in it.(4) Nucleus (vesicular type) It is not visible in an unstained specimen; but its clear structure can be seen when stained with hematoxylin.A: membrane: distinct lineB: chromatin granules: fine and uniformly arranged in the inner surface of the nuclear membrane.C: karyosome: small and centrally located.

Cyst (non-motile) (1) 10-20 mocrometers in size(2) spherical in shape(3) 1-2 nuclei (immature cyst); 4 nuclei (mature cyst-infective stage).(4) inclusions:(become smaller and smaller as the cyst ages) glycogen vacuole appears as a clear space; food reservoir chromatoid body dark blue rods or dots; its function is not known

The single nucleus with its central endosome and regularly distributed chromatin is visible. The dark "rods" in the cytoplasm are the chromatoid bars; approximate size = 18 m. This is a mature cyst and contains four nuclei. However, only two nuclei are visible in this plane of focus, and a chromatoid bar is still present; approximate size = 17 m.

Life Cycle

1 infective stage: mature cyst2 access: mouth3 ecological niches: large intestine; liver, lung and other organs.4 pathogenic stage: trophozoite5 diagnostic stage: cyst; trophozoites

Pathogenic factors1. Toxicity of parasites pathogenic- nonpathogenic complex. Entamoeba histolytica Entamoeba dispar2. Symbiotic bacteria3. Defence barrier immunity

Pathology and Clinical ManifestationPinpoint lesion on mucous membraneFlask-shaped crateriform ulcers

Clinical classificationAsymptomatic infection (carrier) >90% cases (E. dispar?)Sympomatic cases