Virology Flashcards
1
Q
Characteristics: Obligate intracellular; unable to reproduce itself outside host cell
A
Viruses
2
Q
Viruses are acellular and they replicate in ____
A
host cells
3
Q
all viruses are haploid except:
A
retroviruses - diploid
4
Q
Viruses have either __ or __ but not both
A
RNA or DNA
5
Q
Measure of viruses
A
20-300 mm in diameter
6
Q
Virus may be _______: infection that leads to death
A
virulent
7
Q
____ viruses produce infections but do not cause death
A
temperate
8
Q
Entire infectious unit of virus
A
Virion
9
Q
contains the genetic material (either rna or dna)
A
Genome/Nucleic acid
10
Q
encloses the genome; protein in nature; may be helical, icosahedral or complex
A
Capsid
11
Q
Capsid assembling in a cubic manner
A
icosahedral
12
Q
Rod like capsid
A
helical
13
Q
Virus with complex symmetry
A
Poxviridae
14
Q
genome enclosed in a capsid
A
nucleocapsid
15
Q
morphological units on capsid surface
A
Capsomeres
16
Q
smallest functional unit equivalent to building units of the capsid
A
Protomers
17
Q
composed of lipids and polysaccharides: ether sensitive
A
Enveloped
18
Q
without outer membrane: ether resistant/stable
A
Naked/non-enveloped
19
Q
usually seen on enveloped
facilitates transfer of nucleic acid from one host cell to another
A
Protein spikes
20
Q
In general, RNA viruses replicate
A
cytoplasm
21
Q
DNA viruses replicates
A
nucleus
22
Q
suffix: refers to virus family
A
-idae
23
Q
suffix: subfamily classification of virus
A
-inae
24
Q
suffix for genera/genus for virus
A
virus
25
virus-like infectious protein particles causing neurologic diseases in animals and in man
prions
26
Example of prions
Scrapie
Kuru
Creutzfeldt-jakob disease
Bovine spongiform encephalopathy (Mad Cow Disease)
27
Steps in Viral Replication
Attachment/Adsorption
Penetration and uncoating
Biosynthesis (eclipse case)
Morphogenesis/Assembly to produce one virion
Release extracellular fluid
28
Collection period of convalescent specimen in virus
2-3 weeks
29
Before freezing the specimen (virus)
Dilute or emulsify in transport media
30
Best specimen for maximum recovery of viruses
directly aspirated secretions
31
Swabs of viruses must be made with
synthetic swab (dacron fibers or nylon)
32
Calcium alginate swab must be avoided as this is toxic to ____ virus
HSV
33
Urine specimen of virus should be neutralized with ____ to remove vaginal flora
7.5% sodium bicarbonate
34
Blood specimen for viruses recommended volume:
3-5 mL
35
preferred anticoagulant for virus collection
Heparin or Citrate
36
serum specimen preferred anticoagulant ________ for nucleic acid testing of virus
EDTA (pearl top tube)
37
____ inhibits DNA polymerase and therefore not to be used in nucleic acid testing
Heparin
38
Viral Transport Media: maintain pH at ___
7.2
39
Indicator for Viral Transport medium
phenol red
40
Components of viral transport medium
buffered isotonic solution, protein, antibiotics
41
Specimens for virus collection must be kept cool at ____
4 deg C
42
Storage temperature up to 5 days: virus
4 deg C
43
Storage temperature for 6 days or longer: virus
-20 deg C or -70 deg C
44
Storage temperature of virus within 72 hours
2-8 deg C
45
Specimen for freezing/emulsified in VTM dilution
1:2 or 1:5
46
Example of viral transport medium
modified stuart media
modified hanks medium
veal infusion broth
levibovits - emory medium
hank’s balance salt solution
47
Specimen for detecting: influenza virus
Throat swab
48
Specimen for detecting parainfluenza
nasal washing
49
Specimen for detecting RSV (gastroenteritis)
nasopharyngeal aspirate
50
Specimen for detecting norwalk agent
Rectal swab
51
Specimen for detecting rotavirus
stool
52
Specimen for detecting VZV
skin scrapings/lesion swab
53
Specimen for detecting HSV
Vesicular fluid
54
Specimen to rule out CMV
Urine
55
Specimen for detecting ENCEPHALITIS/ASEPTIC Meningitis / togavirus
Blood/CSF
56
least sensitive for virus detection
Direct Microscopic Exam/ Cytology & Histology
57
Used to to visualize pox viruses (largest DNA viruses)
Light microscopy
58
For visualizing virus morphology
Electron microscopy
59
Used to detect viral inclusions (virus particles found in either nucleus and cytoplasm of infected cells)
Phase contrast microscope
60
Viral inclusion: negri bodies
Rabies virus
61
Viral inclusions for Yellow fever virus
Torres inclusion bodies
62
Viral inclusions for Fowl Pox Virus
Bollinger bodies
63
Viral inclusions for Variola and Varizella
Guarneri paschen bodies
63
Cells seen in PAP stained smears
used for diagnostic of HPV infection
Koilocytes
64
atypical squamous with very large nucleus surrounded by a non staining halo
Koilocytes
65
Smear for detection of VZV, HSV inclusion from a stained smear (giemsa/paps - routine stain)
Tzanck smear
66
Gold standard for Virology
Most widely used for virus isolation (shell vial)
Viral culture/Cell culture
67
type of culture that uses normal mature adult cells (passage/use once or twice)
Primary cell culture
68
Most common primary cell culture
Kidney cells (rhesus monkey or rabbit kidney)
69
Primary Monkey Kidney cells (African Green Monkey) are excellent for recovery of
myxoviruses and many enteroviruses, RSV and measles virus, adenoviruses
70
uses embryonic or fetal cells (actively dividing; cell division)
Diploid cell line/ Semi-continuous cell lines
71
Passage of diploid cell line
50
72
Diploid cell line are usually taken from
embryonic tissues; usually fibroblasts from lung or foreskin
73
Diploid cell line for detecting CMV
Human diploid fibroblast/ Human embryonic fibroblast
74
human fetal diploid is used for isolation of
VZV and HSV
75
Continuous cell line uses ___ and passage indefinitely
malignant or cancer cells
76
Cell line for adenovirus, HSV and RSV
Hep-2 continuous cell line
77
From cervical cancer cells
HeLa
78
Hep2 are from ______
laryngeal cancer cells
79
Change in either nucleus or cytoplasm due to the presence of virus
CPE/Cytopathic Effect
80
CPE: Pyknosis condensation of nucleus; exhibited by
picornavirus
81
Formation of fused cells: formation of large cells are seen in
paramyxovirus
82
Vacuoles in cytoplasm: foamy degeneration (type of CPE) seen in
papillomavirus, polyomavirus
83
Swelling and clumping of cells (grape like cluster) are seen in
adenovirus
84
Proliferation of nuclear membrane are seen in
alpha herpes viruses
85
CPE Interpretation: Uninfected monolayer
Negative
86
CPE Interpretation: Atypical alteration of monolayer involving few cells
Equivocal
87
CPE Interpretation: 1% to 25% of monolayer exhibits cytopathic effects (CPE)
1+
88
CPE Interpretation: 25% to 50% of monolayer exhibits CPE
2+
89
CPE Interpretation: 50% to 75% of monolayer exhibits CPE
3+
90
CPE Interpretation: 76% to 100% of monolayer exhibits CPE
4+
91
Viral culture incubation temp
35 to 37 deg C
92
Fluorescein Isothiocyanate: rapid and specific; directly stains virus
Direct Immunofluorescence
93
Fluorescein Isothiocyanate Interpretation: No apple-green fluorescence
Negative
94
Fluorescein Isothiocyanate Interpretation: faint yet unequivocal apple-green fluorescence
1+
95
Fluorescein Isothiocyanate Interpretation: apple green fluorescence
2+
96
Fluorescein Isothiocyanate Interpretation: bright apple-green fluorescence
3+ / 4+
97
refers to the attachment or adherence of the RBCs to the surface of the virus
Hemadsorption
98
Hemadsorption can be observed to those that do not produce CPEs such as: (PIM)
Influenza, Parainfluenza & Mumps
99
Extensive antigenic cross reactivity for serologic testing is seen in
HSV and VZV
Japanese B encephalitis and Dengue
CMV and EBV
100
Test extremely sensitive: to determine viral genome
PCR; Molecular technique
