1. Medical Parasitology Lab.
Artifacts

2. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Definition
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”.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

3. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Blastocystis
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.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

4. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Blastocystis
Raed Z. Ahmed, Medical Parasitology Lab.,2012

5. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Yeast
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.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

6. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Yeast
Yeast
Giardia lamblia cyst
Yeast in an iodine-stained concentrated wet mount of stool. Yeast in wet mount may be confused for Giardia.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

7. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Leukocytes
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.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

8. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Pus
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
Raed Z. Ahmed, Medical Parasitology Lab.,2012

9. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Bacteria
Raed Z. Ahmed, Medical Parasitology Lab.,2012

10. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Coccidia
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.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

11. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Coccidia (cont.)
Raed Z. Ahmed, Medical Parasitology Lab.,2012

12. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Coccidia (cont.)
Raed Z. Ahmed, Medical Parasitology Lab.,2012

13. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Air bubbles
Raed Z. Ahmed, Medical Parasitology Lab.,2012

14. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Oil droplet
Raed Z. Ahmed, Medical Parasitology Lab.,2012

15. Fungal spores Fungal spore Entamoeba histolytica/dispar cyst
Fungal spore in a wet mount of stool.  Such spores may be confused for the cysts of Entamoeba spp.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

16. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Plant fiber
Raed Z. Ahmed, Medical Parasitology Lab.,2012

17. Strongyloides stercoralis larvae
Raed Z. Ahmed, Medical Parasitology Lab.,2012

18. Misdiagnosis can lead to improper treatment
Raed Z. Ahmed, Medical Parasitology Lab.,2012

19. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Hair fiber
Raed Z. Ahmed, Medical Parasitology Lab.,2012

20. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Plant cell
May confused with helminthes eggs
Raed Z. Ahmed, Medical Parasitology Lab.,2012

21. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Planet cell
Plant material in an iodine-stained concentrated wet mount of stool.
This material can be confused for a hookworm egg
Raed Z. Ahmed, Medical Parasitology Lab.,2012

22. Charcot-Leyden crystals
Raed Z. Ahmed, Medical Parasitology Lab.,2012

23. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Epithelial cells
Raed Z. Ahmed, Medical Parasitology Lab.,2012

24. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Macrophages
Raed Z. Ahmed, Medical Parasitology Lab.,2012

25. Raed Z. Ahmed, Medical Parasitology Lab.,2012
RBCs
Raed Z. Ahmed, Medical Parasitology Lab.,2012

26. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Digested meat fibers
Raed Z. Ahmed, Medical Parasitology Lab.,2012

27. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Pollen grains
Raed Z. Ahmed, Medical Parasitology Lab.,2012

28. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Pollen grains
Raed Z. Ahmed, Medical Parasitology Lab.,2012

29. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Soap
Raed Z. Ahmed, Medical Parasitology Lab.,2012

30. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Starch granules
Raed Z. Ahmed, Medical Parasitology Lab.,2012

31. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Crystals
Raed Z. Ahmed, Medical Parasitology Lab.,2012

32. Non- 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.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

33. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Cont.
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 used
Raed Z. Ahmed, Medical Parasitology Lab.,2012

34. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Cont.
Fasciola 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.
Raed Z. Ahmed, Medical Parasitology Lab.,2012

35. Entamoeba . histolytica/ dispar
Intestinal Protozoa
Entamoeba . histolytica/ dispar
Raed Z. Ahmed, Medical Parasitology Lab.,2012

36. 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.,2012

37. Raed Z. Ahmed, Medical Parasitology Lab.,2012
Life cycle
Raed Z. Ahmed, Medical Parasitology Lab.,2012

38. Entamoeba histolytica/ dispar Cyst
Raed Z. Ahmed, Medical Parasitology Lab.,2012

39. Entamoeba histolytica/ dispar Trophozoite
Raed Z. Ahmed, Medical Parasitology Lab.,2012