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Medical Parasitology Lab.

Medical Parasitology Lab. Artifacts. 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. Blastocystis.

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Medical Parasitology Lab.

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  1. Medical Parasitology Lab. Artifacts

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

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

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

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

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

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

  14. 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 Entamoebaspp. Raed Z. Ahmed, Medical Parasitology Lab.,2012

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

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

  21. Plant 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. Epithelial cells Raed Z. Ahmed, Medical Parasitology Lab.,2012

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

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

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

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

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

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

  30. 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

  31. 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

  32. 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

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

  34. Entamoeba histolytica/ dispar • E. histolytica inhabit large intestine and cause amoebic dysentery. • There is two diagnostic stages for E. histolytica/ dispar: • Cystis regular round measuring measure 10 – 20u in diameter with 4 nuclei, and it’s the infective stage. • Trophozoite is the motile form, measure 15-20u in diameter with large nucleus. (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

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

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

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

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