DIAGNOSTIC PARASITOLOGY Flashcards
(122 cards)
1
Q
Liquefy 5 g of phenol crystals with a small amount of distilled water, using a warm water bath at 95 celcius. Dissolve 1 g of basic fuchsin in the liquefied phenol. Add 10 ml of 95% ethanol and mix. Add 100 ml of distilled water. Filter and store in a dark flask, well labelled. The solution is ready for use.
Common Reagents and Preparations
A
Carbol Fuchsin
2
Q
50 mL formaldehyde + 950 mL distilled water or saline (recommended for all-purpose use and for preservation of protozoan cyst).
Common Reagents and Preparations
A
Formalin 5%
3
Q
100 mL formaldehyde + 950 mL distilled water or saline (recommended for helminth eggs and larvae)
Common Reagents and Preparations
A
Formalin 10%
3
Q
2 g potassium iodide (KI) + 1.5 g powdered iodine crystals (add after KI dissolves) + 100 mL distilled water. Store in a brown, glass-stoppered bottle at room temperature and in the dark; the expiration date is 1 year. The solution is ready to use. For routine use, put 20 mL in a brown dropper bottle for 10-14 days.
Common Reagents and Preparations
A
Lugol’s solution
4
Q
Sodium acetate 1.5 g + acetic acid, glacial 2.0 mL + formalin 4 mL + distilled water 92.0 mL
Common Reagents and Preparations
A
SAF (sodium acetate-acetic acid-formalin fixative):
5
Q
simplest and easiest technique to facilitate detection
of intestinal parasites that infected subjects pass in
their feces
A
DIRECT FECAL SMEAR
6
Q
In Direct Fecal Smear, presence of _____________ or _________ can be observed directly with a light microscope
A
intestinal protozoa (trophozoites or cysts)
or helminth eggs
7
Q
In Direct Fecal Smear, small amount of fresh feces is mixed with either ___________ or __________.
A
- saline
- lugol/iodine solution
8
Q
small amount of fresh feces is mixed with _________ (to detect the protozoa motility)
A
saline
9
Q
small amount of fresh feces is mixed with _________ (to reveal the parasite structure).
A
lugol/iodine solution
10
Q
What can you see in a Iodine Preparation
A
cysts of protozoa
10
Q
What can you see in a Saline Preparation
A
- motile trophozoites and larvae
- red blood cells
- Leukocytes
- Charcot–Leyden crystals
11
Q
Types of preparation
A
- Saline Preparation
- Iodine Preparation
12
Q
When examining diarrheic or liquid feces containing mucus, both preparations should be
applied to the _________ of the stools.
A
mucous part
13
Q
- Place 1 drop of saline on the ______ of the slide and 1drop of Lugol’s iodine solution on the _______ of the
slide
PROCEDURE FOR DFS
A
- left side
- right side
14
Q
- Take about ____ of faecal specimen (the amount picked up on the end of an applicator stick) and thoroughly emulsify the stool in the _________
PROCEDURE FOR DFS
A
- 2 mg
- drop of saline
15
Q
- Place a coverslip on each suspension touching the edge of the drop, then gently lower the coverslip onto the slide so that no _________ are produced
PROCEDURE FOR DFS
A
air bubbles
16
Q
- Examine with a ___________.
PROCEDURE FOR DFS
A
microscope
17
Q
Recommended for monitoring large-scale treatment
programmes implemented for the control of soiltransmitted helminth infections because of its simple format and ease of use in the field.
A
Kato-Katz Technique
18
Q
Manner of Reporting in Kato-Katz Technique
A
Eggs per gram stool (epg)
18
Q
Quantify eggs and establishes burden of intestinal infection
A
Kato-Katz Technique
19
Q
Kato-Katz Technique Materials and reagents
A
- Wooden applicator sticks
- screen
- Template
- Spatula
- Microscope slide
- Hydrophillic cellophane
- Flat-bottom jar with lid, forceps and toilet paper
- Newspaper
- Glycerol-malachite green
20
Q
A hole of 9 mm on a 1 mm thick template will deliver about how many mg of faeces?
Kato-Katz Technique
A
50 mg
21
Q
A hole of 6 mm on a 1.5 mm thick template will deliver about how many mg of faeces?
Kato-Katz Technique
A
41.7 mg
22
A hole of 6.5 mm on a 0.5 mm thick template will deliver about how many mg of faeces?
| Kato-Katz Technique
20 mg
23
Size of the hydrophilic cellopane for kato-katz
| Kato-Katz Technique
40-50 um thick
25 x 30 or 35 mm
24
In preparation of Glycerol-malachite green, 1 mL of ______________ is added to 100 ml of __________ and 100 mL of ___________ and mix well.
| Kato-Katz Technique
- 3% aqueous malachite green
- glycerol
- distilled water
25
1. Prepare all the necessary materials:
| Kato-Katz Technique Step by Step Procedure
- template
- nylon screen
- slide
- wooden stick
26
2. Place a small amount of the fecal sample on a ____________ and press a piece of nylon screen on top. Using a _________, scrape the sieved fecal material from the screen.
| Kato-Katz Technique Step by Step Procedure
- newspaper
- spatula
27
3. Label a glass slide with the ________ and place a template with hole on the center of a microscope slide. Fill the hole in the template with the sired fecal material, avoiding air bubbles and levelling the feces off to remove any excess material.
| Kato-Katz Technique Step by Step Procedure
sample number
28
4. Carefully lift off the template and place it in a bucket of water mixed with _____________ and ____________ so that it can be reused.
| Kato-Katz Technique Step by Step Procedure
- concentrated detergent
- disinfectant
29
5. Place one piece of cellophane, which has been soaked overnight in __________, over the fecal sample
| Kato-Katz Technique Step by Step Procedure
glycerol solution
30
6. Invert the microscope slide and firmly press the sample against the __________ on another microscope slide or on a smooth hard surface to spread the feces in a circle
| Kato-Katz Technique Step by Step Procedure
cellophane strip
31
7. Carefully pick up the slide again by gently sliding it sideways to avoid separating the cellophane strip or lifting it off. Place the slide on the bench with the cellophane ________. Water evaporates while ________ clears the feces. When clarified it should be possible to read newspaper print through the stool smear
| Kato-Katz Technique Step by Step Procedure
- upwards
- glycerol
32
For all except hookworm eggs, keep the slide for____________at _________ to clear the fecal material prior to examination under the microscope.
| Kato-Katz Technique
- one or more hours
- room temperature
33
To speed up clearing and examination, the slide can be
placed in a __________ or kept in direct sunlight for
several minutes.
| Kato-Katz Technique
40 °C incubator
33
_________ and __________ will remain visible
and recognizable for many months.
| Kato-Katz Technique
- A. lumbricoides
- T. trichiura eggs
34
Hookworm eggs clear rapidly and will no longer be
visible after ____________
| Kato-Katz Technique
30–60 minutes.
35
___________ may be recognizable for up to several months but it is preferable to examine the slide preparations within 24 hours.
| Kato-Katz Technique
Schistosome eggs
36
The smear should be examined ____________.
| Kato-Katz Technique
systematically
37
Then, multiply by the appropriate FACTOR to give the number of eggs per gram of feces
____ if using a 50 mg template
____ if using a 41.7 mg template
____ if using a 20 mg template
| Kato-Katz Technique
- x 20
- x 24
- x 50
38
Light intensity infections of Ascaris lumbricoides
| Classification of Intensity of Infection
1- 4,999 epg
39
Moderate intensity infections of Ascaris lumbricoides
| Classification of Intensity of Infection
5,000 - 49,999 epg
40
Heavy intensity infections of Ascaris lumbricoides
| Classification of Intensity of Infection
> 50,000 epg
41
Light intesity infections of Trichuris trichiura
| Classification of Intensity of Infection
1 - 999 epg
42
Moderate intensity infections of Trichuris trichiura
| Classification of Intensity of Infection
1,000 - 9,999 epg
43
Heavy intensity infections of Trichuris trichiura
| Classification of Intensity of Infection
> 10,000 epg
44
Light intensity infections of Hookworms
| Classification of Intensity of Infection
1 - 1,999 epg
45
Moderate intensity infections of Hookworms
| Classification of Intensity of Infection
2,000 - 3,999 epg
46
Heavy intensity infections of Hookworms
| Classification of Intensity of Infection
> 4,000 epg
47
Light intensity infections of Schistosoma mansoni
| Classification of Intensity of Infection
1 - 99 epg
48
Moderate intensity infections of Schistosoma mansoni
| Classification of Intensity of Infection
100 - 399 epg
49
Heavy intensity infections of Schistosoma mansoni
| Classification of Intensity of Infection
> 400 epg
50
2 types of blood film for malaria parasites
- Thick blood smear
- Thin blood smear
51
Blood smear used to determine if parasite is present
Thick
52
Blood smear used to confirm the Plasmodium species present
Thin
53
Lysed RBCs
| Thick or Thin Blood Smear
Thick Film
54
larger volume
| Thick or Thin Blood Smear
Thick Film
55
0.25 ul blood/100 fields
| Thick or Thin Blood Smear
Thick Film
56
blood elements more concentrated
| Thick or Thin Blood Smear
Thick Film
57
good screening test
| Thick or Thin Blood Smear
Thick Film
58
positive or negative
| Thick or Thin Blood Smear
Thick Film
59
parasite density
| Thick or Thin Blood Smear
Thick Film
60
more difficult to diagnose species
| Thick or Thin Blood Smear
Thick Film
61
fixed RBCs, single layer
| Thick or Thin Blood Smear
Thin Film
62
smaller volume
| Thick or Thin Blood Smear
Thin Film
63
0.005 ul blood/100 fields
| Thick or Thin Blood Smear
Thin Film
64
good species differentiation
| Thick or Thin Blood Smear
Thin Film
65
requires more time to read
| Thick or Thin Blood Smear
Thin Film
66
low density infections can be missed
| Thick or Thin Blood Smear
Thin Film
67
To quantify malaria parasites against RBCs, count the parasitized RBCs among ____________ on the thin smear and express the results as % parasitemia.
500-2,000 RBCs
68
% parasitemia =
= (parasitized RBCs/total RBCs) × 100
69
If the parasitemia is high [e.g., > 10%], examine _______
500 RBCs
70
If it is parasitemia is low [e.g., <1%] ,examine ___________
2,000 RBCs (or more)
71
In Quantifying Malarial Parasites, Count ___________ and _________ separately.
- asexual blood stage parasites
- gametocytes
72
Only the asexual blood stage parasites are clinically important and gametocytes of ____________ can persist after elimination of asexual stages by drug treatment.
P. falciparum
73
In Quantifying Malarial Parasites againsts WBC, what microscope lens is used?
100x oil immersion lens
74
In Quantifying Malarial Parasites againsts WBC, select area with _______
10-20 WBCs per field
75
In Quantifying Malarial Parasites againsts WBC, count the number of _________ and ______________ in the same fields on thick smear.
- asexual parasites
- white blood cells
76
In Quantifying Malarial Parasites againsts WBC, you need to count how many WBCs
> 200 WBCs
77
In Quantifying Malarial Parasites againsts WBC, assume WBC is ____________
8000/ul
78
parasites per ul =
Parasites counted/WBC counted x WBC count/ul
79
Cellophane swab is used for the diagnosis of:
- Enterobiasis
- Taeniasis
79
Enterobiasis caused by a nematode called?
Enterobius vermicularis
80
Taeniasis caused by tapeworm called?
Taenia solium or Taenia saginata
81
Cellophane Swab is Specimen of choice for the detection of _____________
Enterobius
vermicularis (pinworm) eggs
82
Adult female pinworms may also be seen in __________
Cellophane Swab
83
At night, when the body is at rest, gravid (pregnant) adult female worms exit the host, typically a child, through the rectum and lay numerous eggs in the
________________.
perianal region
84
Time of Collection for Cellophane swab
Early in the morning before the
patient washes or defecates.
85
In cellophane swab, standard protocol for specimens collected daily for the number of negative tests that should be performed to rule out a pinworm infection is ______
5
86
Each worm lay about how many eggs?
10,000 - 11,000 eggs
87
The eggs of Enterobius vermicularis can spread everywhere and become infective in ________
4 - 6 hours
88
In cellophane swab, ____________ may need to explain the procedure to patients, their families, and/or other health care professionals.
Laboratory technicians
89
In cellophane swab, when instructing others, it is also critical to emphasize the importance of exercising ____________ and ___________ during specimen collection to avoid spreading infectious eggs into the environment
- proper hygiene
- preventive measures
90
In Adhesive tape test, what side of the tape to you press on the slide?
Sticky side
91
These procedures allow for the detection of parasitic elements that may be missed when examining only a direct wet smear.
Concentration (sedimentation and flotation)
92
This procedure leads to recovery of ll protozoan cyst and oocysts, helminth eggs and larvae present in the stool specimen
Formalin - ethyl acetate sedimentation concentration
93
It is recommended as being the easiest to perform and the least subject to technical error, allowing recovery of the broadest range of parasitic elements.
Formalin - ethyl acetate sedimentation concentration
94
The specimen can be fresh or fixed stool
Formalin - ethyl acetate sedimentation concentration and concentration by flotation
95
This preparation will often contain more debris than that obtained with the flotation and other procedures
Formalin - ethyl acetate sedimentation concentration
96
Formalin - ethyl acetate sedimentation concentration is not reccomended for ______________________ and ____________________.
- eggs of Fasciola spp.
- larvae of Strongyloides stercoralis
97
In concentration by sedimentation, mix about ____ of faeces with _____ of fixative (SAF or fomalin 5-10%), and leave for at least _______.
- 1 g
- 10 ml
- 30 minutes
98
In concentration by sedimentation, strain the suspension into a ____________ through a sieve or double layer of gauze allocated into a small funnel and centrifuge at _______ for __________
- 15 ml conical tube
- 500 g
- 10 minutes
98
In concentration by sedimentation, the contenst in the tube will separate into four layers:
- sediment (contain parsitic elements)
- saline
- plug of faecal debris
- Top layer of ethyl acetate (or ether or gasoline)
99
This technique allows separation of parasitic elements fromo the coarsest organic debris, using a high specific density flotation solution.
Concentration by flotation
99
Eggs, cysts and oocysts, with a specific density lower than the flotation solution, will rise to the top of the suspension
Concentration by flotation
100
The most widely used flotation solution are:
- zinc sulfate solution
- sodium chloride
101
Heavy eggs such as those of _____________ or _____________ not efficiently concentrated with Concentration by flotation
- Fasciola
- infertile Ascaris eggs
101
In Concentration by flotation, eggs and cyst tend to lose their typical shape after ________
40 - 60 minutes
102
In Concentration by flotation, how many grams of stool do you need to use?
3 g
103
In concentration by flotation, what fixative can you use?
Formalin 5-10%
104
How many g and how long is the first centrifuge of concentration by sedimentation?
- 500 g
- 10 mins
104
How much saline will you add to the sediment after the first centrifuge in concentration by sedimentation?
7 mL
105
How much ethyl acetate will you add to the sediment after adding saline and mixing in concentration by sedimentation?
3 mL
105
In concentration by sedimentation, after adding ethyl acetate, how long will you shake it vigorously?
30 seconds
106
How many g and how long will you centrifuge the second time in concentration by sedimentation?
- 500 g
- 3 mins
106
After the second centrifugation, what are the layers you need to pour off?
| concentration by sedimentation
Top 3 layers
107
What g and how long is the first centrifuge in concentration by flotation?
- 1500 g
- 3 mins
108
after the second centrifugation how much flotation solution will you use to resuspend the sediment?
| concentration by flotation
10 mL
109
How many g and how long is the third centrifugation
| concentration by flotation
- 800-1000 g
- 5 mins
110
Where will you harvest the parasites in concentration by flotation?
upper part of the meniscus
111
What will you use to harvest the upper part of the meniscus in concentration by flotation?
cover slip
