This is not surprising given the economy and culture of this country where pigs play a key role and many pigs are even allowed to live in residences.
Mononucleated wherein nucleus is about 1/3 of the cysts diameter
All antiamebic drugs was used without success, but w/ the used of metronidazole was proved it’seffectiveness alone without the accompanying the diloxanidefuroate.
These pseudopodia are the means by which these organisms move and engulf bacteria and red blood cells for feeding purposes.
The precise transmission mechanisms of BlastocystisHominis remain murky. Fecal-oral transmission is the most accepted pathway, and recent studies have shown that transmission involves only the cyst form (infective stage)of the parasite. The extent to which human-human, human-animal, and animal-human transmission occurs is still unknown, Conclusively stating that BlastocysistisHominis has an animal reservoir depends upon unraveling the true nature of its transmission. If, as Noël et al. deem likely based upon their own molecular work and a review of the literature, animal-to-human transmission is possible, then animals such as pigs and dogs could in fact be acting as a large reservoir capable of human infection
2nd bullet-(e.g., lakes, streams, shallow [less than 50 feet] or poorly monitored or maintained wells).3rd bullet-Recreational water includes water in swimming pools, water parks, hot tubs or spas, fountains, lakes, rivers, springs, ponds, or streams that can be contaminated with feces or sewage from humans or animals.Eating uncooked food contaminated with
Protected by outer shell thus can survive outside host-environment
Study byUdkow and Markell show that same number of stool examination of both a/symptomatic essentially has same prevalenceNo evidence that plays an important role to immunosuppressed persons.
Being stramenophiles is because of formerly characterization of being a non-pathogenic yeast
The CDC recommends that samples be concentrated and at least three separate samples should be taken before a negative result is confirmed. The two most common methods for preparing slides are a wet mount and a trichrome stain. In the wet mount BlastocystisHominis is stained with iodine and appears as a large vacuole in the middle of many small nuclei, though it may be difficult to see. In the trichrome stain, the parasite is stained with trichrome giving the large central body a gray or green appearance and the cytoplasm elements a dark red color
Chemotherapeutic drug Metronidazole- while effective in some individuals, shows signs of resistance by B. hominis or limited effectiveness in others
Blastocystis hominis and e. polecki
• 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
Intestinal parasite of pigs and monkeys
Found occasionally in human
Common intestinal parasite in parts of Papua
New Guinea (19%)
• Cyst and trophozoite
• Cyst’s usual size, 5-11 µm
• Trophozoites’ usual size, 10-12 µm
which is usually round
• 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
• KNOWN AS NON-
• Isoenzyme studies of a
number of isolates- E.
polecki vs E. dispar
• Isoenzyme characterization
(trophozoites)-E. polecki vs.
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
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
Cyst of E. polecki in a wet mount
Stained with iodine. Notice the numerous chromatoid bodies (arrows).
Cysts of E. polecki stained with trichrome.
Notice the large nucleus with a pleomorphic karyosome and numerous
variably-shaped chromatoid bodies.
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.
• Except diloxanide furoate (Furamide) and
• 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
• Pseudoparasite hence non -pathogenic
• Generally consider a nonpathogenic yeast in
• 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
• Accidentally swallowing Blastocystis
'hominis' picked up from surfaces contaminated
with feces from an infected person or animal.
• Drinking water or using ice made from
• 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.
• 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
• Generally when seen in stool, we do not give
significance BUT the pathogenic potential of
Blastocystis may very well depend on
• 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
• Found a DNA-based home w/ highly
diverse protistan group-the
stramenophiles (a vast array of organisms
including brown algae, water molds, and
• Found in the immunocompetent persons
but commonly in patients with GIT
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’
Accurate diagnosis is warranted if this
was the first choice
Cyst of Blastocystis hominis demonstrating its vacuolated
Cyst-forming microbes of varying sizes observed in the
Cyst-forming microbes of varying sizes observed in the
• 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