PARALAB Flashcards
to be continued
What happens if parasites are exposed to high specific gravity,
distortion and shrinkage of protozoan cysts and thin walled nematode eggs may occur
Between PVA and formalin, what reagent could recover most parasites?
formalin
Examples of parasites that can be recovered using FECT
Ascaris lumbricoides
Schistosomes
Hookworm
Capillaria
D.latum
H. nana
Fasciola spp.
In general, helminth eggs, larvae, and protozoan cysts
Facilitates separation of parasites from background debris through the use of saturated table salt solution
BRINE FLOTATION METHOD by WILLIS
How many minutes would leave a coverslip on top of the vial in brine flotation method?
10-15 minutes
It is more efficient for the recovery of cestode eggs and Giardia cyts than ether.
Ethyl acetate
Enumerate the 4 layers of FECT from top to bottom
Ether
Fecal debris
Formalin
Sediments
True or False. The under surface of the coverslip should not come in contact with the brine solution and that no bubbles are trapped.
False, the under surface of the coverslip should come in contact with the brine solution and that no bubbles aretrapped.
What is the main reagent used for zinc sulfate flotation method?
33% Zinc Sulfate
After FECT, this may be used to stain protozoan cyst
2% Iodine Solution
With this procedure, visualization of oocyts can be better appreciated through the use of a phase microscope
SHEATHER”S SUGAR FLOATATION
Why brine flotation is not useful for operculated eggs like Clonorchis, Opistorchis & Heterophyids?
because they have higher specific gravity and thus; do not float in brine solution
No need for centrifugation Low-cost procedure
BRINE FLOTATION METHOD by WILLIS
Arrange the following Brine Flotation procedure:
- Report number of eggs of parasites per coverslip or in plusses.
- Slowly add more brine solution up to the brim of the vial.Carefully lower a cover slip on top of the vial and leave it there for 10-15 minutes.
- Place half a gram stool in vial with a small amount of brine solution.
- After 15 minutes, lift the coverslip squarely and place on a glass slide and examine the entire coverslip under the microscope.
3, 2, 4, 1
What is the use of hydrochloric acid for sedimentation method?
dissolve albuminous material
Why do we need to leave the coverslip on the top of the vial for 10-15 minutes in brine solution method?
During this time interval, helminth eggs will be rising to the top of the solution and stick to the surface of the coverslip.
Why do we need to use tap water in FECT?
to wash fecal sediment and aid in centrifugation until supernatant is clear
Helminth eggs like hookworm & Schistosoma become badly shrunken in this method
BRINE FLOTATION METHOD by WILLIS
What is the principle behind brine flotation method?
The flotation procedure facilitates separation of parasites from
background debris through the use of saturated table salt solution
A method recommended for the recovery of Trichuris, Capillaria, and Schistosoma
Acid-Ether Concentration Technique
Considered the best for the recovery of coccidian oocyts, mainlyCryptosporidium,Cyclospo, and Cytoisospora.
SHEATHER”S SUGAR FLOATATION
flotation method use specifically to recover for both helminth eggs and larvae and protozoan cyst
ZINC SULFATE FLOATATIONMETHOD
Why do we need to leave the coverslip on the top of the vial for 10-15 minutes in brine solution method?
During this time interval, helminth eggs will be rising to the top of the solution and stick to the surface of the coverslip.
Whyuse of ether has been a cause for concern in the laboratory sector?
because of problems in storage and handling of this explosive and flammable compound
Arrange the following procedures for Acid-Ether Technique
- With a clean applicator stick, loosen the interspace film at the acid-ether junction. The acid-ether layers are rapidly poured off.
- Add enough ether (3ml) stopper and shake vigorously for 1 minute.
- Place 5 ml of 40% HCl solution into a tube.
- Strain suspension through one layer of wet gauze and receive in a centrifuge tube
- Shake the sediment and w/ a pipette, transfer a drop into the glass side.
- Report number of parasite eggs counted for the entire coverslip preparation or mount or in plusses
3, 4, 2, 1, 5, 6
In place of ether & ethyl acetate, what may be used in sedimentation procedures?
Gasoline
What is the 3rd layer of FECT consists of?
Formalin
What is the principle behind FECT?
Since the number of parasites form on wet mounts or stained smears may be too low, concentrating the sample may increase the probability of detecting & identifying any diagnostic stage of parasites. This procedure is efficient for the recovery of helminth eggs, larvae. and protozoan cysts that have been preserved with 10% formalin.
In this method, parasite has a lower specific gravity and will therefore float on the surface of the preparation
Flotation Method
Two Types of Concentration Technique
sedimentation , flotation.
Why do we need to let the sample stand for 30 minutes after adding stool with formalin for FECT?
This reduces distortion of protozoan cysts.
Original Zinc sulfate flotation procedure was developed by __________
Faust in 1938
Can separate protozoan cysts and helminth eggs from a large amount of stool based on the differences in specific gravity
Concentration technique
True or False.
Sediments from FECT can be stored for along period of time
True
A method of choice if stool material comes from animals like cats and dogs
Acid-Ether Concentration Technique
In this methods, parasite has a higher specific gravity than the reagent, therefore the parasite will fall to the bottom of the preparation.
Sedimentation Method
What are the two main reagent use for Acid-ether technique?
40% Hydrochloric acid and Ether
Boiled sugar solution preserved with phenol is used in this method
SHEATHER”S SUGAR FLOATATION
Efficient for the recovery of helminth eggs, larvae,and protozoan cysts that have been preserved w/10% formalin
FECT
The only layer in the FECT that you should not decant?
Last layer: sediment
Why do we need to concentrate the sample? What is the principle behind AECT?
Since the number of parasite on wet mount or stained smear may be too low, concentrating the sample will increase the probability of selecting and identifying any diagnostic parasitic stage . HCl is used to dissolve albuminous material. This procedure is recommended for the recovery of Trichuris, Capillaria, & Schistosoma
Ideal number of washing for FECT procedure?
3
In brine flotation method, after putting half a gram of stool in a vial, what must you put next?
Brine solution
A reagent that is used to dissolve neutral fats in stools
Ether
Arrange the following Zinc flotation procedure:
- Centrifuge for 3-5 minutes. Decant the supernatant
- Add zinc sulfate to within 2.5 cm of the rim ofthe tube. Mix thoroughly with an applicator stick
- Place a coverslip and exclude bubbles. Examine the mount immediately or within an hour under the miscroscope.
- Strain a well-mixed fecal suspension through one layer of gauze into a tube
- Carefully transfer the tube into a rack. Avoid disturbing the surface films which now contains the floating parasites. Stand for 1 minute
4, 1, 2, 5, 3
Between PVA and formalin, which could preserved much better parasite morphology?
Formalin
True or False. Mounts prepared from flotation techniques are cleaner than those from sedimentation.
True, because procedures for flotation techniques are easier to conduct unlike with sedimentation that requires numerous washing and straining.
Composition of Brine Solution
NaCl powder- 40 g
Distilled water -100 ml