1. LABORATORY DIAGNOSIS OF PARASITIC INFECTIONS
Lecturer. Mohamed El-Sakhawy

2. Provisional diagnosis
Case diagnosis
History (Age, occupation, residency, previous infection)
Complaint
Clinical examination
Invesigations
- Laboratory investigations
- Radiology
- Surgical intervention (Exploratory)
Provisional diagnosis
Confirm the diagnosis

4. Ether
Dissolve fat
M.f
Acetic acid
RBC haemolysis
Clear ova

5. Clean conical glass receptacle
URINE EXAMINATION
SEDIMENTATION
CONCENTRATION
Clean conical glass receptacle
15-20 min
Centrifuge (2 min)

6. URINE EXAMINATION Membrane filtration technique
air
10 ml urine
Nucleopore filter
+ Saline
Eggs of Schistosoma

7. URINE EXAMINATION HELMINTHES PROTOZOA ARTHROPODES E. vermic. egg
S. haem.egg
E. vermic. egg
S. mansoni egg
Micrfilaria (Ov, Wb)
H sand
Tricomonas. Vaginalis
troph
Pthirus pubis
L. higher deptera

8. URINE EXAMINATION

10. STOOL EXAMINATION

12. STOOL EXAMINATION Temporary
Saline smear
Iodine smear
saline
Iodine 1%
Huge number of:
Eggs
Protozoal troph. Motility
(Amoeb, flagellates)
Huge number of:
Cyst morphological details

13. Staining the saline preparation with methylene blue

14. Lugol iodine–acetic acid solution causes the trophozoite forms to become nonmotile.
Using a fine Pasteur pipette, allow a drop of methylene blue solution to run under the coverslip over the saline preparation (Fig. 7). This will stain the nuclei of any cells present and distinguish the lobed nuclei of polymorphs from the large single nuclei of mucosal cells.
If a drop of eosin solution is added, the whole field becomes stained except for the protozoa (particularly amoebae), which remain colourless and are thus easily recognized.

15. STOOL EXAMINATION Scanty infection Concentration techniques
Sedimentation
Floatation
Non Operculated eggs
Trematodes ( S. m.)
Cestode
Nematode(Hookworms,Trichostong)
Cysts
Heavy eggs (Ascaris egg)
Operculated eggs (Trematodes)
Larvae (Strong sterc.)
Cysts

17. STOOL EXAMINATION Saline sedimentation
Mesh wire gauze
Saline
Emulsify
Conical flask
10 g stool
Sediment

18. STOOL EXAMINATION Formol Ether Sed. Conc.
debris
10% Formalin
formalin
1 g stool
Sediment
Thorough mixing
Conical flask centrif. tube
Ether adsorbs fecal debris & floats.
Formalin fixes & preserves the specimen.

20. Clean light eggs & cysts
STOOL EXAMINATION
Clean light eggs & cysts
Tin container
Seive
20 min
Centrif. 2 min

22. STOOL EXAMINATION Permanent Stained smears
Iron haematoxylin stain
Trichrome stain
Modified Ziehl Neelsen stain (Crptosporidum.)

24. STOOL EXAMINATION Kato technique
Mesh screen
Hole
Template
Remove the template
Cellophane soaked by glycerin (clears faeces(
Egg count/ g stool
Egg quant. Of: Ascaris, T. trich., Hookworms, S. mansoni

25. STOOL EXAMINATION Stoll’s technique
Egg quant. Of: Ascaris, T. trich., Hookworms, S. mansoni
24 hr stool
60 CC
4 g Stool
56 CC
NaOH
Shake well
0.15 CC
Egg count/ slide
Eggs/1g= Eggs/slideX100
Erlynmeyer flask
Egg/day=Eggs/1g X stool wt/g in 24 hrs

26. STOOL EXAMINATION Baermann’s technique
Stool/soil
seive
25-50 CC
Warm water
Glass funnel
30 min
centrifuge
clamp
Detec. Of Nematode L. /stool, soil

27. STOOL EXAMINATION Cultures for Nematode larvae
Filter paper culture
Filter paper
Slide
Sealed petri dish
Water
Scanty infection
Larvae of:
St. stercoralis (A,L)
Hookworms
Trichostrong

29. NaOH
Sputum
Centfifuge

32. floor
Edge

35. BLOOD EXAMINATION BLOOD FILMS
Thin
Thick
Bld drop
Circular motion
spread
Air dry
Air dry
methyl alcohol
Geimsa
Geimsa
Malaria, Babesia, Filaria, Tryp.

36. BLOOD EXAMINATION Buffy coat film
plasma
WBC (BC)
centrifuge
Air dry
Fix
30 min
RBC
spread
Geimsa
Citrated bld
Tryp., L. donovani

37. BLOOD EXAMINATION QBC technique
RBC +parasite
Acridine orange
centrifuge
RBC
Microhaematocrit tube
Malaria, Filaria, Trypanosomes

38. BLOOD EXAMINATION KNOTT’S CONC. TECHNIQUE
Citrated bld
1 ml
10 ml
centrifuge
Air dry
Geimsa
fix
2 min
Formalin 2 %
sediment
Filaria

39. INDIRECT IMMUNOLOGICAL METHODS
Scanty infection.
Tissue parasite no portal of exit (Hydatid dis.)
Migratory stage (Fasciola)
Chronic infection fibrosis (Bilharziasis)

41. INDIRECT IMMUNOLOGICAL METHODS
IHAT
LAT Ag Ag + +
Patient’s serum
(?? AB)
Latex particle
Patient’s serum
(?? AB)
Sensitized
Sheep’s RBC
(O–ve)
Agglutination
Agglutination

42. INDIRECT IMMUNOLOGICAL METHODS INDIRECT FLUORESCENT ANTIBODY TEST
fluorescein
Anti human AB
Patient’s serum
(?? AB)
parasite

43. INDIRECT IMMUNOLOGICAL METHODS ELISA
OPD
Peroxidase E
OPD
Anti human AB
Patient’s serum
(?? AB) AB Ag
Flat bottom plastic micrititre plate

44. INDIRECT IMMUNOLOGICAL METHODS CFT
Sheep’s RBC
Anti sheep AB
+ve Ab
No Sheep RBChaemolysis AB
complement
Patient’s serum
(?? AB)
-ve Ab Ag
haemolysis
Tube / microplate

45. INDIRECT IMMUNOLOGICAL METHODS Double Electro Immuno Diffusion
Line of ppt
Electric current
+ve Ab Ag
-ve
Buffered gel

46. INDIRECT IMMUNOLOGICAL METHODS Immunodiagnostic Strip Test (Dip Stick Test) Ag
+ve
-ve
Pt bld (?Ag)
Coloured dye
Monoclonal Ab
Nitrocellulose strip
Malaria, Filaria, African tryp.

48. MOLECULAR BIOLOGICAL TECHNIQUES DNA Probes
Radio active material
Commercially prepared DNA sequence
DNA Probe
Hybridization
+ve parasite
Nitrocellulose paper
Sample (Serum/ stool)
?? parasite
Radioactivity

49. MOLECULAR BIOLOGICAL TECHNIQUES Polymerase Chain Reaction (PCR)
Single stranded DNA
Replication
Detection
T cruzi, T gondii

50. 10 X Objective

51. Relative sizes of helminth eggs as seen in microscope field using the 10 objective (with 10 eye-pieces). Eggs are as
seen in a saline preparation.
1. E.vermicularis, 2. A.lumbricoides, 3. S.stercoralis larva (motile), 4. Hookworm, 5. T.trichiura, 6. D.latum, 7. O.sinensis,
8. Fasciola sp, 9. S.mansoni, 10. Paragonimus sp, 11. S.japonicum, 12. S.intercalatum, 13.Taenia sp, 14.V.nana, 15. H.dimunuta.

52. 40 X Objective

53. Relative sizes of trophozoites and cysts of intestinal protozoa, common nematode eggs and larva of Strongyloides as seen in microscope field using the 40 objective (with 10 eyepieces).
1. I.belli oocyst, 2. A lumbricoides egg, 3. Leucocytes, 4. E.histolytica/E.dispar cyst, 5. E.histolytica trophozoite (motile),
6. Red cells, 7. S.stercoralis larva (motile), 8. E.coli cyst (mature), 9. G.lamblia cyst, 10. C.mesnili cyst, 11. Hookworm
egg, 12. G.lamblia trophozoite (motile).
Iodine preparation: 13. E.coli cyst, 14. I.buetschlii cyst, 15. E.histolytica/E.dispar cyst, 16. V.nana cyst, 17. T.trichiura egg,
18. Blastocystis hominis, 19. G.lamblia cyst.

54. Non-parasitic structures found in faeces: Care
must be taken not to report as parasites those structures that can be normally found in faeces such as:
muscle fibres, vegetable fibres, starch cells (stain blue-black with iodine), pollen grains, fatty acid crystals, soaps, spores, yeasts, and hairs .
Large numbers of fat globules may be seen in faeces when there is malabsorption.
Charcot Leyden crystals (breakdown products of eosinophils) can sometimes be seen in faeces (also in sputum) in parasitic infections. They appear as slender crystals with pointed ends, about 30–40m in length

55. Structures found in faeces that required differentiation from parasites.

56. Image illustrating Red Blood Cells in slide preparation.
Image illustrating Fat Globules in slide preparation
Image illustrating Yeast Cells in slide preparation
Note similarity to parasitic oocysts.
Image illustrating Vegetable cell in slide preparation.

57. Image illustrating Vegetable Spiral in slide preparation.
Image illustrating a Vegetable Spiral in slide preparation. Such spirals may appear similar to proglottids.
Image illustrating Vegetable cell in slide preparation.

58. Image illustrating geranium pollen cells in slide preparation.
Image illustrating pollen in slide preparation that could be mistaken for a Taenia egg. The shell is thinner, of non-uniform thickness, and no hooks are visible.
Image illustrating pollen resembling a Hymenolepis nana egg. Hooks and polar filaments are not visible.
Image illustrating geranium pollen cells in slide preparation.
Image illustrating pollen in slide preparation using a color filter

59. Image illustrating vegetable hairs in slide preparation.
Image illustrating peach hair in slide preparation. Note the similarity to Strongyloides stercoralis.
Image illustrating vegetable hairs in slide preparation.