Artifacts Raed Z Ahmed Medical Parasitology Lab2012 Definition Artifacts other things living or artificial present in the stool that are not parasites and could mislead the laboratory ID: 360297
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Slide1
Medical Parasitology Lab.
ArtifactsSlide2
Raed Z. Ahmed, Medical Parasitology Lab.,2012Definition
Artifacts:
other things, living or artificial, present in the stool that are not parasites and could mislead the laboratory
worker.
Note:
“Artifacts not to be mistaken for cysts”.Slide3
BlastocystisRaed Z. Ahmed, Medical Parasitology Lab.,2012
Round or oval, sometimes with angular irregular edges, contain one large vacuole taking up almost the whole cell, the compressed cytoplasm forms a granular ring round it.Slide4
Blastocystis
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide5
Yeast Raed Z. Ahmed, Medical Parasitology Lab.,2012
Oval, often with buds, often contain eccentric cluster of 3-6 small granules.
Some related forms of yeast are rectangular, with a very clear oval cytoplasm inside: arthrospores
.Slide6
Yeast Raed Z. Ahmed, Medical Parasitology Lab.,2012
Yeast in an iodine-stained concentrated wet mount of stool. Yeast in wet mount may be confused for Giardia.
Yeast
Giardia lamblia
cystSlide7
Leukocytes Raed Z. Ahmed, Medical Parasitology Lab.,2012
Round or slightly elongated, with an irregular outline.
Contain refractile cytoplasm, clear and granular with tiny vacuoles.
Nucleus indistinct, sometimes with a star- shaped false karyosome. Slide8
Pus Raed Z. Ahmed, Medical Parasitology Lab.,2012
Pus can be seen by the naked eye as opaque, greyish streaks( not transparent like mucus).
Under the microscope it appears as a mass of more or less degenerate leukocytes Slide9
Bacteria
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide10
Coccidia Raed Z. Ahmed, Medical Parasitology Lab.,2012
These are protozoa that may be parasite of men without causing any significant pathogenic effects, or may be found in transit in stool following the consumption of infected foods.
They appear in stool in a form resembling cyst called oocysts or sporocysts.
An elongated oval, sometimes tapered at one pole.
There three types:
4 sporozoites (small banana shaped rods), each containing a small round nucleus, sometimes a few large granules massed at one pole.
One large round granular cell.
Refractile granules completely fill the interior. Slide11
Coccidia (cont.)
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide12
Raed Z. Ahmed, Medical Parasitology Lab.,2012Coccidia
(cont.) Slide13
Raed Z. Ahmed, Medical Parasitology Lab.,2012Air bubblesSlide14
Oil droplet Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide15
Fungal spores Raed Z. Ahmed, Medical Parasitology Lab.,2012
Fungal spore in a wet mount of stool. Such spores may be confused for the cysts of
Entamoeba
spp.
Fungal spore
Entamoeba histolytica/dispar cystSlide16
Plant fiber Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide17
Strongyloides stercoralis larvae
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide18
Misdiagnosis can lead to improper treatmentRaed Z. Ahmed, Medical Parasitology Lab.,2012Slide19
Hair fiber
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide20
Plant cell
Raed Z. Ahmed, Medical Parasitology Lab.,2012
May confused with helminthes eggsSlide21
Planet cellRaed Z. Ahmed, Medical Parasitology Lab.,2012
Plant material in an iodine-stained concentrated wet mount
of stool.
This
material can be confused for a hookworm eggSlide22
Charcot-Leyden crystalsRaed Z. Ahmed, Medical Parasitology Lab.,2012Slide23
Epithelial cellsRaed Z. Ahmed, Medical Parasitology Lab.,2012Slide24
Macrophages Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide25
RBCs
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide26
Digested meat fibersRaed Z. Ahmed, Medical Parasitology Lab.,2012Slide27
Pollen grainsRaed Z. Ahmed, Medical Parasitology Lab.,2012Slide28
Raed Z. Ahmed, Medical Parasitology Lab.,2012Pollen grainsSlide29
SoapRaed Z. Ahmed, Medical Parasitology Lab.,2012Slide30
Starch granules Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide31
Crystals Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide32
Raed Z. Ahmed, Medical Parasitology Lab.,2012Non- parasitic structure found in stool
Non parasitic objects may be misidentified as parasites. The differentiation of the most common pseudoparasites is as follow:
Protozoan cyst
: may be confused with air bubbles, fat globules or yeasts.
Iodine should be added to the wet preparation so that the internal structure of the cyst is stained and identifiable.
Amoebic trophozoites:
must be differentiated from non- pathogenic protozoan trophozoites and macrophages.
Trophozoites of
Entamoeba histolytica/dispar
must be motile and hematophagus.
Macrophages found in cases of intestinal amoebiasis are distinguishable from amoebic trophozoites by possessing a larger nucleus and, although they can haematophagus, they are only motile for a very short time. Their pseudopodia are small, blunt and granular. Slide33
Raed Z. Ahmed, Medical Parasitology Lab.,2012Cont.
Ova, their general shape, except for
Entrobius
, is perfectly symmetrical, distinguishing them from various objects found in stools.
Trichuris
and
Taenia
ova may be confused with pollen grains.
Ascaris
ova may be confused with vegetable cells, the latter having smooth, thick walls but irregular shape.
Strongyloides
or hookworm larvae can be confused with hair or vegetable fibers. The latter are usually tapered at one end and the other being blunt and with no internal structure.
Free living nematode larvae may be found in concentrates if contaminated water is usedSlide34
Raed Z. Ahmed, Medical Parasitology Lab.,2012Fasciola ova resemble vegetable cells.
Insect and may be found in stools as spurious infection
.
Mite eggs may be confused with hookworm eggs.
Dipylidium caninum
eggs sacs can look similar to vegetable cells.
Other structure found in stool are crystals, Charcot- Leyden are the breakdown products of eosinophil cells and may be present in stools or
sputum.
Starch
granules are sometimes seen in stool. When undigested, they appear as concentric rings and stain blue with iodine, when partially digested, they stain red.
Cont.
Slide35
Entamoeba . histolytica/ dispar
Intestinal Protozoa
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide36
Entamoeba histolytica/ dispar
E. histolytica inhabit large intestine and cause amoebic dysentery.
There is two diagnostic stages for E. histolytica/ dispar:
Cyst
(infective stage).
Trophozoite
(motile
form, motility by
pseudopodia).
Diagnosis:
Stool examination to see cyst stage, or trophozoite stage if the sample is fresh.
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide37
Life cycle
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide38
Entamoeba histolytica/ dispar Cyst
Raed Z. Ahmed, Medical Parasitology Lab.,2012Slide39
Entamoeba histolytica/ dispar Trophozoite
Raed Z. Ahmed, Medical Parasitology Lab.,2012