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
