Flotation Methods Medical parasitology lab. Faculty of health sciences Medical Laboratory Sciences Department Medical parasitology lab. Flotation Methods

Concentration Methods Sedimentation method Modified Formal- Ether sedimentation technique Acid- Ether sedimentation technique Flotation method Saturated Salt Solution technique Sheather’s Sugar Centrifugal Flotation technique Zinc Sulphate Centrifugal Flotation technique

Flotation technique Advantage: Disadvantage: These method use the high specific gravity of a solution to float the lighter ova and cyst. They can be improved by centrifugation. Advantage: Easy to perform . Disadvantage: Delay in examination can result in distortion. Larvae and some fluke eggs do not concentrate. Frequent checking of specific gravity.

Saturated salt solution Flotation Methods Saturated salt solution

Materials and Method Boil granular sodium chloride in excess in water to produce a saturated solution which when cooled has a specific gravity of 1.18 - 1.2. Half fill a wide- mounted flat bottomed container with the saturated salt solution. Emulsify 1gm of feces in the solution and strain it to remove the debris from the surface. Pour the filtrate into meniscus and fill it to the top with saturated salt solution. Lay a glass slide or large coverslip over the top, avoiding any bubbles being trapped. Leave for 20 min before quickly inverting the slide. Scan for ova using the 10x objectives.

Saturated Salt solution technique Advantages: It is cheap preparation using simple apparatus. It concentrates nematode ova well. Disadvantages: It doesn’t concentrate cysts.

Sheather’s Sugar Centrifugal Flotation Technique Flotation Methods Sheather’s Sugar Centrifugal Flotation Technique

Materials and Method Sheather’s sugar solution: Table sugar --------------------------------------500gm Distilled water ---------------------------------- 320ml Phenol crystal ( melt in hot water bath) ----- 6.5gm

Procedure: Soften 1gm of feces with water to a soft. Strain the aqueous suspension through a wire sieve. Mix 1 part aqueous suspension with 2 part of Sheather's sugar solution. Pour into a centrifuge tube, centrifugation 1500 rpm for 10 minutes. Pour the supernatant into a meniscus and add a sufficient solution to bring the meniscus to the top. Place a coverslip and wait for 10 minutes. Examine under microscope.

Sheather’s Sugar solution technique Advantages: Reveals most nematode eggs and protozoan cyst. Disadvantages: Flukes eggs and tape worm eggs are not demonstrate well. Also most nematode larvae are not demonstrate well.

Entamoeba histolytica/ dispar E. histolytica inhabit large intestine and cause amoebic dysentery. There is two diagnostic stages for E. histolytica/ dispar: Cyst is 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.

Entamoeba histolytica/ dispar

Entamoeba histolytica/ dispar Trophozoite

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