protozoan-amoeba

3. • Entamoeba Polecki was first
identified in 1912 in Czechoslovakia
by Von Prowazek in the stool samples
of two students from Kampuchea.
• E. Polecki was repeatedly found in
pig feces, but no other human cases
were reported until 1949
• Maybe asymptomatic or mistaken as
E. histolytica

4. Intestinal parasite of pigs and monkeys
Found occasionally in human
Common intestinal parasite in parts of Papua
New Guinea (19%)
Pig-to-human transmission
Human-to-human transmission

6. • Cyst and trophozoite
• Cyst’s usual size, 5-11 µm
• Trophozoites’ usual size, 10-12 µm
which is usually round

7. • Almost all of entamoeba spp are
morphologically identical and of the
size range, BUT CAN BE
DIFFIRENTIATED BY isoenzyme
analysis, restriction fragment length
polymorphism and typing with
monoclonal antibodies.

8. • KNOWN AS NON-
PATHOGENIC
• Diarrhea
• Isoenzyme studies of a
number of isolates- E.
polecki vs E. dispar
• Isoenzyme characterization
(trophozoites)-E. polecki vs.
E. chattoni

9. Stage & preparation Characteristics
Trophozoites, unstained Not characteristic
Trophozoites, stained Suggestive: nucleus with minute central
karyosome, w/ peripheral chromatin
evenly distributed or massed at one or
both poles; ingested bacteria
Cysts, unstained Suggestive: uniform mononuclear
condition
Cysts, stained (iodine) Suggestive: mononucleated cysts; large
central karyosomes w/ evenly
distributed peripheral chromatin or
massed at one or both poles
Diagnostic: inclusion masses,
chromatoidal bars w/ angular or pointed
ends.

10. Cyst of E. polecki in a wet mount
Stained with iodine. Notice the numerous chromatoid bodies (arrows).

11. Cysts of E. polecki stained with trichrome.
Notice the large nucleus with a pleomorphic karyosome and numerous
variably-shaped chromatoid bodies.

12. Trophozoites of E. polecki stained with trichrome
The single nucleus is often distorted and irregularly-shaped, with a small
to minute centrally-located karyosome. Peripheral chromatin is usually
delicate and uniform. The cytoplasm is often vacuolated with a hyaline
border. Blunt pseudopodia may be seen.

13. • Except diloxanide furoate (Furamide) and
metronidazole (Flagyl)
• Pilot by Salaki and coworkers (1979)
• 750mg 3x/ daily for 10 days with 500mg 3x/
daily for 10 days
• 750mg 3x/ daily for 5,7, or 10 days

14. • Kingdom: Protista
• Subkingdom: Protozoa
• Phylum: Sarcomastigophora
• Subphylum: Sarcodina
• Superclass: Rhizopoda
• Class: Lobosea
• Subclass: Gymnamoeba
• Order: Amoebida
• Suborder: Blastocystina
• Genus: Blastocystis
• Species: Hominis

15. • Pseudoparasite hence non -pathogenic
• Generally consider a nonpathogenic yeast in
the past
• Some maintain that it has protozoan affinities,
although on the basis of rRNA sequencing, its
phylogenetic affinities are less clear (Johnsons
et al., 1989)
• Inhabitant of the human intestinal tract
• Binary fission
• Having pseudopod extension and retraction

17. • Accidentally swallowing Blastocystis
'hominis' picked up from surfaces contaminated
with feces from an infected person or animal.
• Drinking water or using ice made from
contaminated sources
• Swallowing recreational water contaminated
with Blastocystis 'hominis'.
• Traveling to countries where Blastocystosis is
common and being exposed to the parasite as
described in the bullets above.

18. • The classic form that is usually seen in stool
specimens varies in size from 6 - 40mm and is
characterized by a large membrane bound
central body which occupies 90% of the cell.
It has no internal nuclear structure and a rim
of peripheral granules the function of which is
not known.

19. • Generally when seen in stool, we do not give
significance BUT the pathogenic potential of
Blastocystis may very well depend on
subtype.
• 95% of humans colonized by Blastocystis
have one of the following subtypes: ST1, ST2,
ST3, ST4 hence acknowledge as pathogen
• Organism has been associated with nausea,
fever, vomiting, diarrhea and abdominal
pain.

20. • Found a DNA-based home w/ highly
diverse protistan group-the
stramenophiles (a vast array of organisms
including brown algae, water molds, and
diatom)
• Found in the immunocompetent persons
but commonly in patients with GIT
disorders

21. Type of preparation Characterization
Iodine preparations The peripheral layer is light yellowish and
the nuclei position is clearly indicated
Permanent stains Central material has intense stain, stain
lightly or may not stain at all; the nuclei
is dark, and embedded
PCR and culture use/Fields’
and Giemsa
Accurate diagnosis is warranted if this
was the first choice

22. Iodine stained

23. Trichome stained

24. Romanowski’s stain
Cyst of Blastocystis hominis demonstrating its vacuolated
cell wall.

25. Giemsa stained
Cyst-forming microbes of varying sizes observed in the
feces

26. Papanicolaou stained
Cyst-forming microbes of varying sizes observed in the
feces

27. • Several said that it is still unidentified.
• no single drug or no particular diet appears to be
capable of eradicating Blastocystis
• Chemotherapeutic drug Metronidazole- most
widely used treatment option
• Nitazoxanide- recent study,
has been with much more
positive effects, with 86% of
those treated with the drug
effectively cured