Page 20 - MNU-PM503 Parasitology practical book

Pharm D- Clinical Pharmacy Program Third Level Parasitology and virology (PM503)

b. Take about 2 mg of stool, with an applicator stick, and thoroughly emulsify it in

saline.

c. Cover with cover slip and examine microscopically.

d. A new mount can be prepared with iodine alone.

e. The iodine will stains protozoan cysts for second examination.

The direct saline smear is used mainly to detect motile protozoan trophozoites.

The iodine will kill trophozoites present, thus no motility will be seen after the iodine

is added.

ii- Kato Thick-Smear Technique:

Egg-counts made by this technique are used for the quantitative diagnosis of

helminth infections.

2- Concentration Techniques:

a- Sedimentation Methods: Three methods are of value.

i- Simple Saline Sedimentation: Like urine

ii- Formalin-Ether Sedimentation Technique:

This technique leads to the recovery of all protozoan cysts, and helminthic eggs

and larvae present. Formalin is added for fixation and preservation of the parasitic

stages, while ether is used as an extractor of debris, fat and oils from the stool. Also,

fecal debris absorbs ether and becomes lighter than the sediment.

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