Intestinal Amebae Clinical Microbiology Review 236
AMEBA NUCLEUS TROPH CYST PATHOGENICITY OTHER
Entamoeba
histolytica
Only ameba
that ingests
RBCs. EIA for
antigen
detection.
Molecular test-
ing available.
Round.
Fine, even
peripheral
chromatin.
Small, deli-
cate, central
karyosome.
10–60 μm, average 20 μm.
1 nucleus. Delicate, finely granular
cytoplasm. Ingested RBCs. Seldom
contains bacteria. Single, long,
finger-like pseudopod. Directional
motility.
Round. 10–20 μm. 2–4 nuclei. 10%
have cigar-shaped chromatoid bodies.
May have glycogen vacuoles.
Causes acute
amebic dysen-
tery. Can cause
extraintestinal
amebiasis.
(From Leventhal R, Cheadle RF.
Medical Parasitology: A Self-
Instructional Text, 5th ed.
Philadelphia: FA Davis; 2002:91.)
(From Leventhal R, Cheadle RF. Medical
Parasitology: A Self-Instructional Text,
5th ed. Philadelphia: FA Davis;
2002:91.)
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