intestinal amoeba for clinical parasitology

a guide to intestinal amoebas

1. PRESENTED
BY
GROUP 3
INTESTINAL
AMOEBA
INTESTINAL
AMOEBA

2. ENTAMOEBA HISTOLYTICAENTAMOEBA HISTOLYTICA
A. TROPHOZOITE STAGE (I&H PREPARATION)
SHAPE: IRREGULAR
SIZE: 10-60 น
STRUCTURES:
CYTOPLASM IS GRAYISH VIOLET WITH A
CLEAR DEMARCATION BETWEEN THE
ECTOPLASM AND ENDOPLASM
ENDOPLASM IS BRIEFLY GRANULAR WITH
INGESTED RBC WHICH ARE BLUISH BLACK
IN COLOR
SINGLE, SPHERICAL VESICULAR NUCLEUS;
THE NUCLEAR MEMBRANE IS LINED BY
FINE, REGULARLY ARRANGED CHROMATIN
GRANULES; KARYOSOME IS RELATIVELY
SMALL AND CENTRALLY LOCATED

3. Shape: spherical
Size: 5-20 u
Structures:
smooth, definite, relatively thin cystic
wall
number of nuclei range from 1-4,
rarely more, with a centrally located
karyosome
in the younger cyst, the chromatoidal
bars with rounded ends and glycogen
mass may be present
I & H PREPARATIONI & H PREPARATION
cytoplasm is grayish violet,
granular
nuclei are clearly seen with dark
stained central karyosome
if present, the chromatoidal bars
are blue-black color
if present, the glycogen mass is
unstained
cytoplasm is grayish violet,
granular
nuclei are clearly seen with dark
stained central karyosome
if present, the chromatoidal bars
are blue-black color
if present, the glycogen mass is
unstained
the cyst wall is refractile and relatively
thin
the cytoplasm is colorless with a ground
glass appearance
nuclei are rarely visible, sometimes one
may appreciate the outline of the nucleus
if present, the glycogen mass is clear or
empty space in the cytoplasm
if present, the chromatoidal bars are
refractile
the cyst wall is refractile and relatively
thin
the cytoplasm is colorless with a ground
glass appearance
nuclei are rarely visible, sometimes one
may appreciate the outline of the nucleus
if present, the glycogen mass is clear or
empty space in the cytoplasm
if present, the chromatoidal bars are
refractile
NSS PREPARATIONNSS PREPARATION
CYST
STAGE
CYST
STAGE

4. IODINE PREPARATIONIODINE PREPARATION
TROPHOZOITE IN LIVER
ABSCESS
TROPHOZOITE IN LIVER
ABSCESS
the cytoplasm is greenish
yellow
the nuclei are clearly seen
with central karyosome
if present, the chromatoidal
bars are refractile
if present, the glycogen mass
is dark yellowish brown in
color
TROPHOZOITE IN
INTESTINAL ABSCESS
TROPHOZOITE IN
INTESTINAL ABSCESS

5. A. TROPHOZOITE STAGE (I&H PREPARATION)
SHAPE: IRREGULAR
SIZE: 10-60 น
STRUCTURES:
CYTOPLASM IS GRAYISH VIOLET WITH A
CLEAR DEMARCATION BETWEEN THE
ECTOPLASM AND ENDOPLASM
ENDOPLASM IS BRIEFLY GRANULAR WITH
INGESTED RBC WHICH ARE BLUISH BLACK
IN COLOR
SINGLE, SPHERICAL VESICULAR NUCLEUS;
THE NUCLEAR MEMBRANE IS LINED BY
FINE, REGULARLY ARRANGED CHROMATIN
GRANULES; KARYOSOME IS RELATIVELY
SMALL AND CENTRALLY LOCATED
ENTAMOEBA COLIENTAMOEBA COLI

6. CYST
STAGE
CYST
STAGE
CYSTIC STAGE
SHAPE: SPHERICAL
SIZE: 10-33
STRUCTURES: * SMOOTH, DEFINITE
THICK CYSTIC WALL
NUMBER OF NUCLEI RANGES FROM
1-8, RARELY MORE WITH AN
ECCENTRIC KARYOSOME
IN YOUNGER CYSTS,
CHROMATOIDAL BARS WITH
SPLINTERED ENDS AND GLYCOGEN
MASS MAY BE PRESENT
NSS PREPARATION
REFRACTILE CYST WALL *
CYTOPLASM IS COLORLESS *
NUCLEI ARE FAIRLY VISIBLE AS
REFRACTILE RINGS
IF PRESENT, THE CHROMATOIDAL
BODIES ARE REFRACTILE
STRUCTURES * IF PRESENT, THE
GLYCOGEN MASS IS A CLEAR OR
EMPTY SPACE IN THE
CYTOPLASM
MAY BE PRESENT 4. I&H
PREPARATION * CYTOPLASM
IS GRANULAR, GRAYISH VIOLET
* NUCLEI ARE CLEARLY VISIBLE
WITH DARK STAINED
ECCENTRIC KARYOSOME * IF
PRESENT, GLYCOGEN MASS IS
UNSTAINED 5. NSS
PREPARATION

7. CYST
STAGE
CYST
STAGE
IODINE PREPARATION *
CYTOPLASM IS YELLOWISH
BROWN
NUCLEI ARE CLEARLY SEEN
WITH ECCENTRIC
KARYOSOME
IF PRESENT,
CHROMATOIDAL BODIES
ARE REFRACTILE * IF
PRESENT, GLYCOGEN MASS
IS DARK BROWN IN COLOR

8. Unusual in two respects:
It in habits in the mouth rather than in the large intestine
Only trophozoite stage exists; no cystic stage
TROPHOZOITE STAGE
ENTAMOEBA GINGIVALISENTAMOEBA GINGIVALIS
shape: irregular
size: 5 - 35 µm
Structures:
a. Clear separation between ectoplasm and granular
endoplasm.
b. Endoplasm contains food vacuoles with bacteria and
rarely RBCs.
c. Single spherical nucleus with a central karyosome.
d. Multiple pseudopodia for directional movement.

9. TROPHOZOITE STAGE
ENDOLIMAX NANAENDOLIMAX NANA
A non-pathogenic intestinal amoeba
Commonly found in human intestine
Important in differentiating pathogenic amoebas
It can be misidentified as Entamoeba Histolytica (pathogenic)
Shape: Irregular
Size: Small (6-15 µm)
Key Structures:
Cytoplasm: Grayish violet, vacuolated, may
contain bacteria
Nucleus: Small, spherical, vesicular, with a large
irregular karyosome anchored by achromatic
fibrils
in I & H stained smear

10. CYST STAGE
ENDOLIMAX NANAENDOLIMAX NANA
Shape: Oval
Size: 6-10 µm
Key Structures:
Definite, smooth
cyst wall
1-4 nuclei
Chromatoidal
bodies (small,
curved rods,
occasionally
present)
I & H stained smear
Cytoplasm: Grayish,
granular
Nuclei: Dark-stained
dots
Chromatoidal bodies:
Deeply stained, small,
slightly curved rods
NSS stained smear Iodine stained smear
Cyst wall:
Refractile
Cytoplasm:
Colorless
Nuclei: Faintly
visible
Cytoplasm: Yellowish
Nuclei: Visible as dots
Glycogen mass:
Usually absent or
diffused with ill-
defined margins

11. IODAMOEBA BUETSCHLIIIODAMOEBA BUETSCHLII
A. TROPHOZOITE STAGE (I&H PREPARATION)
1. SHAPE: IRREGULAR
2. SIZE: 6-25 U
3. STRUCTURES:
A. GRANULAR, VACUOLATED CYTOPLASM
AND VACUOLES MAY CONTAIN BACTERIA
AND YEAST CELLS
B. SINGLE, SPHERICAL NUCLEUS WITH A LARGE
CENTRAL OR ECCENTRIC KARYOSOME
SURROUNDED BY AN UNSTAINED HALO.
KARYOSOME IS ANCHORED TO THE NUCLEAR
MEMBRANE BY ACHROMATIC FIBRILS

12. CYST STAGE
IODAMOEBA BUETSCHLII IODAMOEBA BUETSCHLII
Cystic Stage
1. Shape: irregular
2. Size: 6-15 μ
3. Structure:
a. Smooth, definite
cystic wall
b. Single nucleus, rarely
with 2 nuclei
c. Large glycogen
vacuole
I & H stained smear
Cytoplasm: Violet-gray,
granular
Nuclei: visible
Chromatoidal bodies:
usually absent; if
present, they are seen
as deeply stained small
rods
NSS stained smear Iodine stained smear
Cyst wall: Refractile,
relatively thick
Cytoplasm:
Colorless
Nuclei: not visible
Glycogen vacoules:
unstained or empty
space in cytoplasm
Cytoplasm: Yellowish
Nuclei: may be visible
Glycogen vacoule:
dark brown

13. TROPHOZOITE - UNSTAINED PREPARATION
Entamoeba coli
Sluggish, rarely progressive
DIFFERENCE BETWEEN ENTAMOEBA
HISTOLYTICA AND ENTAMOEBA COLI
DIFFERENCE BETWEEN ENTAMOEBA
HISTOLYTICA AND ENTAMOEBA COLI
Shape
Entamoeba histolytica
Irregular Irregular
Color Glassy
Ground glass
Size 10-60u (larger)
15-50u (smaller)
Motility Active progressive
Inclusions
Pseudopod
Finger shaped, hyaline, glasslike
and rapidly extruded
Blunt and short, more granular,
slowly extruded
Ingested RBC, no bacteria
No ingested RBC, bacteria present
Ectoplasm &
Endoplasm
Clear ectoplasm and
refractile endoplasm
Not well differentiated

14. D’ANTONI’S IODINE STAINED
Entamoeba coli
DIFFERENCE BETWEEN ENTAMOEBA
HISTOLYTICA AND ENTAMOEBA COLI
DIFFERENCE BETWEEN ENTAMOEBA
HISTOLYTICA AND ENTAMOEBA COLI
Nucleus
Entamoeba histolytica
Visible spherical
nucleus with minute
central karyosome
Visible spherical
nucleus with thick
nuclear membrane,
large karyosome

15. CYST - UNSTAINED AND STAINED
Shape
Entamoeba histolytica
Spherical
Size
5-20u (smaller)
Nuclei
4 rarely more
Karyosome
Centrally located
Entamoeba coli
8 rarely more
DIFFERENCE BETWEEN ENTAMOEBA
HISTOLYTICA AND ENTAMOEBA COLI
DIFFERENCE BETWEEN ENTAMOEBA
HISTOLYTICA AND ENTAMOEBA COLI
Spherical
10-33 (larger)
Chromatoid bodies
Eccentric
Rods with rounded ends Rods with broom-like ends
Cytoplasm color
Greenish yellow Yellowish brown

16. E. histolytica E. coli E. nana I. buetschlii *D. fragilis
size 10-60 μm 15- 50 μm 6- 15 μm 6-25 μm 3-22 μm
shape when at rest
rounded but slightly
irregular
same same same same
motility
tongue-like
pseudopodia protude
with explosive force
sometimes in one
direction and with
rapid succession giving
rise to a progressive
directional crawl
broad, short
pseudopodia sluggishly
protude and lazily with
drawn, has a sluggish
progressive directional
crawl
short, blunt, sluggish
pseudopodia
same as E. coli
triangular, lobose or
with serrated edges,
sometimes with
progressive movement
endoplasm and
inclusions
"clean". RBC in food
vacuoles
"dirty", highly
vacuolated with
bacteria and food
debris in food
vacuoles, no RBC
vacuolated, with
bacteria, no RBC
same as E. nana same as E. nana
nucleus
invisible except in
flowing endoplasm
during progressive
crawl; in old
trophozoites
degenerated nucleus
are seen as black ring
almost always visible
as a grayish or black
ring
sometimes seen as
grayish blue
same as E. nana not visble
DIFFERENTIAL CHARACTERISTICS OF
INTESTINAL AMOEBA AND A
AMOEBAFLAGELLATE
DIFFERENTIAL CHARACTERISTICS OF
INTESTINAL AMOEBA AND A
AMOEBAFLAGELLATE
living trophozoite normal saline wet mount

17. E. histolytica E. coli E. nana I. buetschlii *D. fragilis
size 5-20 μm 10-30 μm 6- 10 μm 6-15 μm no cyst
shape rounded rounded rounded or oval
rounded or odd shape,
triangular, pear,
kidney shape
chromatoid bodies
abundant bars with
rounded ends or cigar
shape rods
scanty, spicules or
blocks with sharp
points
not visible not visible
glycogen
rare, insufficient
amount to change
appearance of cyst
young cyst is filled with
glycogen mass
no glycogen mass
visible
majority have well
defined dense glycogen
ball, slightly refractile,
light blue not
nucleus
not visible except in
old cyst
visible except when
concealed in young
cyst by glycogen mass
not visible visible
DIFFERENTIAL CHARACTERISTICS OF
INTESTINAL AMOEBA AND A
AMOEBAFLAGELLATE
DIFFERENTIAL CHARACTERISTICS OF
INTESTINAL AMOEBA AND A
AMOEBAFLAGELLATE
living cyst
normal saline wet mount

18. criteria Identified Amoeba
with ball-like refractile glycogen mass
and odd or distorted shape
Iodamoeba buetschlii
without glycogen ball, usually
faultlessly spherical or oval
-
size classification
Large ( ≥ 18 u in diameter) Entamoeba coli
Medium ( 10 - 17 u in diameter) -
Small (<10 u in diameter) -
KEY TO THE CYST OF INTESTINAL AMOEBAE AS SEEN IN
NORMAL SALINE SOLUTION WET MOUNT
KEY TO THE CYST OF INTESTINAL AMOEBAE AS SEEN IN
NORMAL SALINE SOLUTION WET MOUNT

19. criteria Identified Amoeba
Chromatoid body
rod shaped, rounded ends Entamoeba histolytica
Rod-shaped, splintered ends, >4
nuclei
Entamoeba coli
Shape and Visibility of Chromatoid
bodies
Oval or sausage-shaped, chromatoid
bodies not visible
Endolimax nana
KEY TO THE CYST OF INTESTINAL AMOEBAE AS SEEN IN
NORMAL SALINE SOLUTION WET MOUNT
KEY TO THE CYST OF INTESTINAL AMOEBAE AS SEEN IN
NORMAL SALINE SOLUTION WET MOUNT
Special Note: Dientamoeba fragilis has no cystic stage but may resemble E.
histolytica when immobile

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PRESENTATION
THANK
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THANK
YOU!