INTRODUCTION TO PARASITOLOGY Flashcards
1
Q
Area of biology with the phenomenon of dependence of one living organism on another (live on and obtain their nutrients)
A
Parasitology
2
Q
Living together the association of two living organisms, each of a different species
A
Symbiosis
3
Q
Association of two different species of organisms that is beneficial to one and neutral to the other
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Commensalism
4
Q
Association of two different species of organisms that is beneficial to both
A
Mutualism
5
Q
Association of two different species of organisms that is beneficial to one at the other’s expense
A
Parasitism
6
Q
Relating to commensalism; the association between two different organisms in which one benefits and has a neutral effect on the other
A
Commensal
7
Q
Parasite that has demonstrated the ability to cause disease
A
Pathogenic
8
Q
Parasite living inside the body of a host
A
Endoparasite
9
Q
The presence of an endoparasite causes
A
Infection
10
Q
Parasite living outside the body of a host
A
Ectoparasite
11
Q
The presence of an ectoparasite causes
A
Infestation
12
Q
Parasite that depends entirely upon host for existence
A
Obligate Parasite
13
Q
May exist in a free-living state or may become parasitic when the need arises
A
Facultative
14
Q
Parasite which establishes itself in a host where it does not ordinarily live.
A
Incidental/Accidental Parasite
15
Q
Remains in or on a host for its entire life cycle
A
Permanent
16
Q
Lives in the host for a short period of time
A
Temporary Parasite
17
Q
Free-living organism that passes through the digestive tract without infecting the host
A
Spurious
18
Q
Harbors the sexual stage / adult stage of the parasite
A
Definitive/Final host
19
Q
Harbors the asexual or larval stage of the parasite
A
Intermediate host
20
Q
Harbors the parasite; it will only serve as a transport medium; no further development occurs.
A
Paratenic host
21
Q
Harbors parasite; allows the parasite life cycle to continue and become additional sources of human infection
A
Reservoir host
22
Q
Sources of infection
A
Soil
Water
Food
Arthropods
Animals
Another person
Autoinfection
23
Q
Modes of transmission
A
Sexual Intercourse
Inhalation of airborne eggs
Mouth / Ingestion / Oral – Fecal Route
Skin penetration
Arthropods
Congenital Transmission
Transmammary infection
24
Q
Most common mode of transmission
A
Ingestion
25
Responsible for transmitting the parasite from one host to another
Vectors
26
3 P's of Parasitoloogy
Parasite
People
Poverty
27
Vector that is essential to parasite life cycle
Biologic Vector
28
Vector that only transport parasite
Mechanical
29
Morphologic forms that invade humans
Infective stage
30
Morphologic form detected via laboratory retrieval method
Diagnostic stage
31
What is the importance of knowing the life cycle of parasite?
Helps in deciding the specimen to be collected, frequency, and timing of the collection
32
Body areas commonly associate with parasitism
Gastrointestinal and urogenital tracts
Blood and tissue
Liver, lung and other major organs
Miscellaneous locations such as cerebrospinal fluid, eye, skin and extremities
33
Most common symptoms associated with parasitic disease processes
Diarrhea
Abdominal pain
Fever
Abdominal cramping
Chills
34
Most commonly submitted sample in the laboratory
Stool
35
The most common procedure in the examination of stool
Ova and Parasites (O&P) Examination
36
3 separate protocols of stool examination
Direct wet smear
Concentration technique
Permanent stained smear
37
Stool examination that provides preliminary result
Direct wet smear
Concentration technique
38
Stool examination that provides definitive result
Permanent stained smear
39
Typical stool collection protocol consists of how many specimen?
3 specimens
40
Number of stool sample/s required to diagnose amobiasis
6 stool samples for 14 days
41
Stool samples are best collected using
Clean, wide-mouthed containers made of waxed cardboard or plastic with a tight-fitting lid
42
Ideal amount of formed stool for examination
Thumb size/walnut-sized specimen (2-5g)
43
Ideal amount of watery stool for examination
5-6 tablespoons of watery stool
44
Liquid stools should be examined within
30 minutes
45
Semiformed stools should be examined within
Within 60 minutes
46
Formed stools should be examined within
Up to 24 hours
47
Storage requirement for stool specimen
3-5C/Refrigerator temperature
48
Effect of refrigeration to trophozoites
It kills it
49
Should we freeze or incubate stool samples when there is a delay in examination?
Never freeze, never keep them in incubator
50
Medications that may interfere with the detection of parasites
Barium
Bismuth
Laxatives
Anti-diarrheals
51
How to collect specimens in patient using medications?
Stool should be collected prior the therapy or a week (5-7 days) after the last intake of these drugs
52
When should we collect specimen from patients using antibiotics or antimalarial drugs?
2 weeks following therapy
53
Normal color of stool
Brown
54
Indication of black stool
May indicate upper GI tract bleeding
55
Indication of fresh blood in stool
May indicate lower GI tract bleeding
56
Soft or liquid stools may suggest the presence of
Protozoan Trophozoites
57
Formed stool may suggest the presence of
Cysts
58
Liquid or Formed stools may suggest the presence of
Helminth eggs
59
All-purpose fixative
Formalin
60
Stool : Preservative Ratio
1:3
61
Formalin concentration recommended for protozoan cyst
5%
62
Formalin concentration recommended for helminth eggs and larvae
10%
63
Fixative that is routinely used for direct examinations and concentration
Formalin
64
Can we use formalin for permanent stained smear?
No
65
Considered the gold standard fixative
Schaudinn’s solution
66
Advantage of Schaudinn’s solution
Permanent stained smear / excellent preservation
67
Disadvantage of Schaudinn’s solution
Contains mercuric chloride (highly toxic)
68
Plastic resin that serves to adhere to stool sample onto slide
Polyvinyl Alcohol (PVA)
69
Advantage of Polyvinyl Alcohol (PVA)
Preparation for permanent stained smear
70
Disadvantage of Polyvinyl Alcohol (PVA)
Not good for concentration technique and antigen tests; use of mercuric chloride
71
Advantage of Sodium Acetate Formalin
Mercury free, used for concentration technique permanent stained smear, and can be used for staining with modified acid fast stain to detect coccidian oocyst
72
Disadvantage of Sodium Acetate Formalin
Images are not as sharp after staining
73
Eco-friendly fixative
Modified Polyvinyl Alcohol
74
Advantage of Modified Polyvinyl Alcohol
Mercury free
75
Specimen required for Direct wet preparation/ Direct Fecal Smear/ Direct Wet Mount
Fresh stool
76
Purpose of Direct wet preparation/ Direct Fecal Smear/ Direct Wet Mount
To observe motile trophozoites
77
Saline concentration for the detection of trophozoites
Saline (0.85% NaCl) mount
78
What is the purpose of Glycerine in Kato Thick smear?
Clearing solution
79
What is the purpose of Malachite green in Kato Thick smear?
Minimize background
80
Kato Thick smear is good in detecting eggs with ____ but not for ____
Thick shells; hookworms
80
Does the Kato Thick smear technique able to detect protozoan cyst and trophozoites?
No
81
What is the purpose of concentration techniques?
To detect small numbers of parasites
To remove debris that might mask the parasites
82
Can we use concentration technique to detect protozoan trophozoites? Why?
No, protozoan trophozoites do not usually survive the procedure
83
Advantage of Sedimentation techniques
Good for heavy eggs; settles at the bottom
84
Advantage of Floatation technique
Good for Light eggs: egg floats
85
Clinical importance of Sedimentation technique
Best technique for the recovery of Schistosoma (heavy spine), Operculated eggs, Trematode eggs, Cestode eggs, Trichuris trichuria eggs and Capillaria philippinensis
86
Clinical importance of Floatation technique
Best technique for recovery of Protozoan cyst, Nematode eggs except Trichuris trichuria eggs and Capillaria philippinensis (heavy due to bipolar plugs)
87
Most widely used sedimentation technique
Formalin-Ethyl Acetate Concentration Technique
88
Main reagents of FEACT and their functions
10% Formalin: all purpose fixative
Ether/ Ethyl acetate: dissolves neutral fats/ lipids and CHO
89
Main reagent of Zinc Sulfate Floatation
33% Zinc solution
90
In Zinc Sulfate Floatation, what is the specific gravity of fresh tool specimen?
1.18
91
In Zinc Sulfate Floatation, what is the specific gravity of formalin preserved specimen?
1.20
92
What happens if parasites are exposed to high specific gravity?
Distortion and shrinkage of protozoan cyst and thin walled nematode eggs may occur
93
Best for recovery of coccidian oocysts
Sheather’s Sugar Floatation
94
Coccidian species detected by Sheather’s Sugar Floatation
Cryptosporidium, Cyclospora, Cytoisospora
95
Final procedure in the O & P examination
Permanent Stains
96
Why is it that permanent stains are not recommended for the identification of helminth eggs or larvae?
These parasites stain too dark or appear distorted
97
Helminth eggs and larvae are best detected and identified using
Concentration technique
98
Sample of choice in permanent stain procedure
PVA preserved specimen
99
How does permanent stain slides are reviewed?
Slides are reviewed under OIO; 300 fields are reviewed before considered negative
100
Most widely used permanent stain
Wheatley Trichrome
101
Stain used for the detection of oocyst of coccidians
Modified Acid Fast
102
Difference between Modified Acid Fast and Conventional Acid Fast
Weaker decolorizer - 1-3% Sulfuric Acid
103
Stain used for the detection of Microsporidia
Modified Trichrome
104
Difference between Modified Trichrome and Conventional Trichrome
10x more dye
105
Uses a measured amount of stool which has been sieved through a wire mesh
Kato-Katz Method
106
Kato-Katz Method is useful for assessing the intensity of infection with
(SHAT)
Schistosoma
Hookworm
Ascaris
Trichiuris
107
Standard multiplication factor of Kato-Katz Method
24
108
In Kato-Katz method, the cellophane coverslips must be soak in the glycerine mixture for at least
24 hours
109
Most widely used dilution egg counting procedure
Stoll dilution egg count
110
Stool diluent used in Stoll dilution egg count and its function
0.1 NaOH; saponifies fat and frees egg from debris
111
Amount of sample required in Stoll dilution egg count
4g feces
112
What is the factor to determine EPG in Stoll dilution egg count
100
113
Baermann Funnel Technique is based on
Active migration or movement of larvae from feces suspended in water
114
In Bearmann procedure, what is the material used to wrap stools that are mixed with moist soil?
Gauze/Cheeseclot
115
Uses test tubes and filter paper strips
Harada – Mori / Test tube method culture
116
Test used to differentiate Hookworms from Threadworms
Harada – Mori / Test tube method culture
117
In the Harada-Mori test how do you determine if the larva is hookworm or threadworm?
Filariform larva will move downwards and be recovered from the water at the bottom of the tube
Strongyloides larvae may instead move upwards and accumulate at the upper end of the filter paper strip
118
Test used to collect duodenal aspirate for the diagnosis of Giardiasis
Enteric Capsule Test/Entero Test/String test
119
When performing EnteroTest, how do you determine if the yarn actually reached the duodenum?
Yarn must be color green or yellow-green due to the uptake of bile (bile is secreted in the duodenum)
120
Gold standard for the detection E. vermicularis
Cellophane Tape Preparation / Scotch Tape Method
121
Ideal time to collect specimen when using Scotch Tape Method?
Early in the morning before the patient has taken a bath or before the patient has washed the perineum. Or late at night
122
Why does E. vermicularis eggs are rarely seen in stool?
They can hatch at a very short period of time
123
Demonstation and rapid diagnosis of malarial parasites
Thick films
124
Useful in species identification
Thin smears
125
Stain of choice in Thin smear
Giemsa
126
How should we review Thin smear slides?
300 or more OIF in 15 to 20 minutes
127
Capillary tube used in Capillary Tube method
Heparinized capillary tube
128
Concentration technique used in cases of low microfilaria
Knott’s Concentration Technique
129
Efficient technique when microfilaria are of low density
Membrane Filtration Technique
130
Medium used for the recovery of hemoflagellates
Novy-Mcneal-Nicole (NNN medium)
131
Culture medium used for opportunistic free-living amoebas
Culture on non-nutrient agar seeded with Eschericia coli
132
Causes African sleeping sickness
Trypanosoma brucei complex
133
Useful in the diagnosis of Trichinella spiralis
Muscle biopsy
134
Method of choice for the detection of Onchocerca volvulus
Skin biopsy / Skin nips
135
Best specimen to examine for the detection of P. westermanii egg
First morning specimen (sputum)
136
Inductants used to increase the amount of sputum collection
10% sodium chloride or hydrogen peroxide
137
The use of antihelminthic drugs in an individual or public health
Deworming
138
Refers to the number of previously positive subjects found to be egg-negative on examination of a stool or urine sample using a standard procedure at a set time after deworming
Cure Rate
139
Is the percentage fall in egg counts after deworming based on examination of a stool or urine sample using standard procedure at a set time after treatment
Egg reduction Rate
140
Involves individual level deworming with selection for treatment based on a diagnosis of infection or an assessment of the intensity of infection or based on presumptive grounds
Selective Treatment
141
Group level deworming where the risk group to be treated may be defined by age, sex, or other social characteristics irrespective of infection status
Targeted Treatment
142
Is population level deworming in which the community is treated irresepective of age, sex, infection status or other social characteristics
Universal Treatment
143
Refers to the proportion of the target population reached by an intervention
Coverage
144
Is a genetically transmitted loss of susceptibility to a drug in a parasite population that was previously sensitive to the appropriate therapeutic dose
Drug resistance
145
The effect of a drug against an infective agent in ideal experimental conditions and isolated from any context
Efficacy
146
Measure of the effect of a drug against an infective agent in a particular host, living in a particular environment with specific ecological, immunological, and epidemiological determinants
Effectiveness
147
The avoidance of illness caused by infections
Morbidity control
148
Health education strategy that aims to encourage people to adapt and maintain healthy Life practices
Information-education-communication
149
The planning, organization, performance, and monitoring of activities for the modification and/or manipulation of environmental factors or their interaction with human beings with a view to preventing or minimizing vector or intermediate host propagation and reducing contact between humans and the infective agent
Environment management
150
Involves interventions to reduce environmental health risks including the safe disposal and hygienic management of human and animal excreta, refuse, and waste water.
Environmental sanitation
151
Is the provision of access to adequate facilities for the safe disposal of human excreta, usually combined with access to safe drinking water
Sanitation
152
Defined as a permanent reduction to zero of the worldwide incidence of infection caused by a specific agent, as a result of deliberate efforts.
Eradication
153
Reduction to zero of the incidence of a specified disease in a defined geographic area as a result of deliberate efforts.
Elimination
154
Urine should not be allowed to contaminate in the stool. True or False?
True
155
Effect of urine in stools contaminated with parasites
It destroys some parasites
156
Both stain and fixative
Merthiolate- Iodine Formalin (MIF)
157
Universal fixative
TOTAL-FIX
158
Semiuniversal Fixative
SAF: contains formalin (no mercury and PVA)
ECOFIX: contains PVA (no mercury and formalin)
159
No formalin, mercury and PVA
Universal fixative: TOTAL-FIX
160
Time required glycerine to clear fecal material
1 hour
161
Recommended stool examination method by WHO
Kato-Katz Method
162
Amount of stool required for Direct Method of Beaver
2mg
163
How to examine thick films
100 OIF in 5 to 10 minutes
164
Does Giemsa stain sheath of W. bancrofti?
No, use hematoxylin based instead (Delafield’s hematoxylin)
165
Process of Knott’s Concentration Technique
1 ml blood + 9 ml of 2% formalin – centrifuge (500xg for 1 minute) – discard supernantant – examine sediment (smeared and stained)
166
Examination of CSF must be within
20 minutes
167
Globular structure exhibiting jerky tumbling motility
T. vaginalis
168
Chyluric sample
W. bancrofti
169
Hematuria lacerate bladder
S. haematobium
170
Fecal contamination
E. vermicularis
