MLT069: PARASITOLOGY LABORATORY
1. Illustrates the importance and drawbacks of salt floatation methods?
Answer 1: These methods 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.
➢ Flotation Methods
a) Saturated Salt Methods
Material
1. 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.
2. Half fill a wide- mounted flat bottomed container with the saturated salt solution. 3.
Emulsify 1gm of feces in the solution and strain it to remove the debris from the surface.
4. Pour the filtrate into the meniscus and fill it to the top with saturated salt solution. 5.
Lay a glass slide or large coverslip over the top, avoiding any bubbles being trapped. 6.
Leave for 20 min before quickly inverting the slide.
7. Scan for ova using the 10x objectives.
Advantages:
● It is cheap preparation using simple apparatus.
● It concentrates nematode ova well.
Disadvantages:
● It doesn’t concentrate cysts.
b) Sheather’s Sugar Centrifugal Flotation Technique
Material and method
■ Sheather’s sugar solution:
● Table sugar --------------------------------------500gm
● Distilled water ---------------------------------- 320ml
1. Illustrates the importance and drawbacks of salt floatation methods?
Answer 1: These methods 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.
➢ Flotation Methods
a) Saturated Salt Methods
Material
1. 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.
2. Half fill a wide- mounted flat bottomed container with the saturated salt solution. 3.
Emulsify 1gm of feces in the solution and strain it to remove the debris from the surface.
4. Pour the filtrate into the meniscus and fill it to the top with saturated salt solution. 5.
Lay a glass slide or large coverslip over the top, avoiding any bubbles being trapped. 6.
Leave for 20 min before quickly inverting the slide.
7. Scan for ova using the 10x objectives.
Advantages:
● It is cheap preparation using simple apparatus.
● It concentrates nematode ova well.
Disadvantages:
● It doesn’t concentrate cysts.
b) Sheather’s Sugar Centrifugal Flotation Technique
Material and method
■ Sheather’s sugar solution:
● Table sugar --------------------------------------500gm
● Distilled water ---------------------------------- 320ml
