Unit 1 - Virology Intro Flashcards
(155 cards)
1
Q
What year did Edward Jenner use cowpox from a milkmaid to vaccinate an 8 year old?
A
May 14 1796
2
Q
What year was small pox eradicated?
A
1980
3
Q
What year was HIV defined as the cause of AIDS?
A
1983
4
Q
What year did David Baltimore and Howard Temin discover reverse transcriptase and retroviruses?
A
1970
5
Q
What is one thing host cells can never replicate from viruses?
A
RNA
6
Q
Negative Sense =
A
non-coding
7
Q
An older term for AR-thropod BO-rne virus. Includes the Bunyaviridae, Togaviridae, some Orbiviruses, and Rhabdoviruses.
A
Arbovirus
8
Q
a virus parasitizing bacterium; bacterium + to eat
A
bacteriophage
9
Q
the protein coat of a virus
A
capsid
10
Q
individual structural proteins that collectively make up the capsid
A
capsomeres
11
Q
a virus particle having a capsid, but an incomplete nucleic acid content, or and empty particle, which interferes with replication of complete particles
A
defective interfering particle
12
Q
the phospholipid covering derived from host cell membranes, either nuclear or cytoplasmic (plasma membrane or endoplasmic reticulum) present on some viruses
A
envelope
13
Q
a polyhedral shape composed of 12 vertices (corners) and 20 triangular faces; cubic symmetry
A
icosahedron
14
Q
a structural term denoting the combined nucleic acid and capsid; may be helical or cubic in symmetry
A
nucleocapsid
15
Q
a virus isolated in the absence of disease
A
orphan virus
16
Q
a gylcoprotein subunit projecting from the enveloped referred to as “spikes” that function in attachment to host cells
A
peplomere
17
Q
unconventional agents of disease resulting in spongiform encephalopathies by proteins that cause protein folding anomalies.
A
prions
18
Q
the process by which base sequences in mRNA produce specific amino-acid sequences in a protein
A
translation
19
Q
the process of forming mRNA from nucleic acid, no necessarily DNA
A
transcription
20
Q
an individual viral particle
A
virion
21
Q
a class of infectious agents, ocurring in plants that are smaller than viruses and consist of short strands of RNA without a capsid
A
viroids
22
Q
complex molecular particle, capable of infecting cells and causing disease by redirecting host cellular synthetic machinery towards the synthesis of new infectious particles
A
virus
23
Q
Where do most DNA viruses replicate? RNA viruses?
A
cell nucleus; cytoplasm
24
Q
What are the six steps of the replication cycle?
A
- Attachment
- Penetration
- Uncoating
- Synthesis
- Assembly/Maturation
- Release
25
What do viruses look for to attach to host cells?
specific receptors
26
What are the two methods of penetration or entry into the host cell?
fusion, endocytosis
27
Which type of penetration is only seen in enveloped viruses?
fusion
28
List two methods used for release from the host cell?
cell lysis, budding
29
all proteins in a mature virus particle even if they make no contribution to the morphology or rigidity of the virion
structural protein
30
viral proteins found in the cell but not packaged into the virion
non-structural protein
31
morphologic changes in the host cells caused by viruses
CPE (cytopathic effect)
32
List the two uses of CPE:
1. identify the virus isolate
| 2. quantitate infectious virus particles by the plaque-forming unit
33
the first in vitro cultures of cells taken directly from the organs
primary culture
34
a cell line that can be subcultured and grow continuously
cell-line
35
interaction between host and virus affecting development and outcome of an infection:
host-virus relationship
36
What are the two types of host response to viral infections?
non-specific, specific
37
Which antibody is produced earliest?
IgM
38
What is IgM composed of?
pentamer of 5 IgG molecules
39
stimulate cytotoxic cellular response and activate B cells
T helper cells
40
control and regulate the cytotoxic cellular response by suppressing Th cells
T suppressor cells (Ts)
41
main effector cells which kill virus-infected target cells
cytotoxic T cells (Tc)
42
release macrophage activation factor
delayed hypersensitivity T cells (Td)
43
direct killing of virus-infected cells
NK cells
44
modulate immune response
IL-1, IL-2
45
injection of antibodies that can temporarily protect against infection
artificial passive immunization
46
the transfer of maternal antibody from dam to fetus or newborn
natural passive immunity
47
What is the most applicable way of preventing viral disease?
immunization
48
Are the replication enzymes of parvovirus coded for and supplied by the host cell?
yes
49
What are the parvovirus replication enzymes?
DNA dependent RNA polymerase, DNA dependent DNA polymerase
50
Describe the genetic information for parvovirus:
small single linear strand of DNA
51
Parvovirus is associated with what species?
dogs
52
Panleukopenia is associated with what species?
cats
53
What is the virus that causes parvo in cats?
FPV
54
What are the symptoms of feline parvovirus?
enteritis, teratogenesis; cerebellar hypoplasia or aplasia
55
What are the viruses that cause parvo in dogs?
CPV, MPV
56
What are the symptoms of canine parvovirus?
enteritis, myocarditis
57
What is parvovirus called in Geese?
Derzy's dz virus, DDV
58
What are the symptoms of parvo in geese?
hepatitis, enteritis, influenza, myocarditis
59
What are the symptoms of parvo in pigs?
mummified or aborted fetuses
60
What are the symptoms of parvovirus in cows?
enteritis, repro. disease
61
What are the name associations for parvovirus in cows?
BPV, or HADEN virus
62
List the 8 steps of viral infection of host cells:
1. attachment 2. penetration 3. uncoating 4. transcription 5. translation 6. replication 7. assembly 8. release
63
At what stage do enveloped viruses gain their lipid bilayer to allow for cytocidal or persistent infection?
release
64
How was parvovirus first recognized pathologically?
producing malformations in the brains of rats and hamsters
65
Canine Parvovirus in utero exposure results in:
fetal death/abortion
66
Canine Parvovirus in neonates <2 weeks old results in:
generalized infection leading to acute death at 10-14 days old
67
Canine parvovirus in neonates 3-8 weeks old results in:
death < 3 months, cardiac arrhythmias; death >3 months, myocardial fibrosis
68
Canine parvovirus from oronasal exposure for over 8 week old puppies can affect what three different areas?
1. lymphoid, tissue, marrow
2. intestinal epithelial cells
3. lungs, liver, kidneys
69
Does anything happen if parvovirus infects the lungs, liver, or kidneys?
minimal pathology
70
All parvoviruses are:
cytocidal
71
When is the ideal time to collect specimens for viral isolation?
during the acute stage of illness before antibodies form
72
How are viruses grown in lab (on what type of material)?
embryonated eggs, cell cultures, liver animals
73
What is used in direct method detection of viruses?
the virus itself, or components antigens or molecules of the virus
74
What is used in indirect method detection of viruses?
serologic evidence in the form of specific antibodies
75
Why will many viruses replicate in embryonated chicken eggs?
because the cells and extra-embryonic membranes of the developing embryo lack a high degree of specialization
76
List 5 reasons chicken embryos are used almost exclusively:
1. availability
2. economy
3. convenient size
4. relatively aseptic
5. lack of antibody production
77
List the six methods of inoculating embryonated chicken eggs?
yolk sac, chorioallontoic cavity, chorioallantoic membrane, amniotic sac, IV, intracerebral
78
What type of cells do viruses readily grow in when the chicken embryos are innoculated via the chorioallantoic cavity?
entodermal cells
79
List the 5 factors influencing the growth of viruses in chicken embryos:
age, route of inoculation, concentration/volume of virus, incubation temperature, and time of incubation
80
What is the most common method for isolation of viruses from clinical material?
cell cultures
81
Cell culture denotes the growing of cells...
in vitro
82
a tissue culture started from material taken directly from an animal
primary cell culture
83
What types of animal inoculations are there?
intracerebral, intranasal, intraperitoneal
84
best chance for successful propagation of an unknown virus is in the:
natural host (animal inoculation)
85
What animal is used for intracerebral inoculation?
mice
86
What animal is used for intranasal inoculation?
mice, sometimes ferrets
87
What animal is used for intraperitoneal inoculation?
guinea pigs, (and less commonly) rats
88
Tissue of choice for samples from intraperitoneal inoculation:
spleen
89
How do we morphologically characterize viral particles?
TEM with phosphotungstic acid negative staining
90
What parts of an animal can you test with TEM?
excretions, secretions, and solid tissues
91
What additive allows for easily sedimentation of viruses and why?
antibody; causes viral particles to clump
92
detection of virus/viral antigen involves capture by specific antibody attached, either absorbed or covalently bound, to a solid substrate
ELISA
93
What is the result of an ELISA based on?
a visible color change following the addition of a substrate
94
Are ELISAs direct or indirect?
both
95
List the 4 direct methods of viral detection we went over (includes some under the category of BOTH):
ELISA, PCR, radioimmunoassay, electron microscopy, fluorescent antibody test
96
What is the only significant difference between radioimmunoassay and the ELISA?
the indicator system is isotope labeled antibody rather than enzyme labeled antibody
97
method being used to detect and analyze most infectious agents:
PCR
98
frequently applied in the detection and analysis of certain viruses, many of which utilize RNA in their genetic code
RT-PCR
99
an enzyme that catalyzes the formation of DNA from an RNA template
reverse transcriptase
100
spread by the blood stream:
viremia
101
List the 3 mechanisms of spread in the body:
1. local spread on epithelial surfaces
2. subepithelial invasion and lymphatic spread
3. viremia
102
What is the most important route of virus shedding?
respiratory
103
What is the least important route of virus shedding?
skin
104
List the 7 virus shedding routes:
respiratory, skin, feces, saliva, genital secretions, urine, milk
105
infections that persist for the life of the animal, although episodes of clinical disease might occur infrequently:
persistent infections
106
Why are persistent infections important?
1. source of infection
2. reactivation
3. immunopathologic disease
4. associated with neoplasms
107
virus is not demonstrable except when reactivation occurs:
latent infections
108
virus is always demonstrable and often shed and disease may be absent, chronic, or may develop late
chronic infections
109
virus gradually increases during a very long preclinical phase, leading to a slowly progressive lethal disease
slow infections
110
like an extracellular plasmid
episome
111
Where do most prions concentrate?
brain and spinal cord
112
misfolded proteins that concentrate in the tissues of the CNS
prions
113
3 Modifications of host defense mechanisms:
1. defective antibody response 2. defective cell-mediated immunity 3. growth in macrophages
114
Why is it beneficial for viruses to grow in macrophages?
avoid host immune response
115
interaction between host and virus affecting development and out come of an infection
host-virus relationship
116
What are the two types of host-response to viral infections?
non-specific, specific (kind of like innate versus adaptive)
117
a molecule which induces the formation of antibody
antigen
118
a single antigenic determinant as a smallest unit of antigen
epitope
119
a molecule produced by animals in response to antigen
antibody
120
B lymphocytes respond to an antigenic stimulus by producing and secreting specific antibodies
humoral immunity
121
responds to an antigenic stimulus by the activation of several kinds of T lymphocytes and the production and secretion of several kinds of lymphokines
cell-mediated immunity
122
earliest antibody produced:
IgM
123
What is IgM made of?
pentamer of 5 IgG molecules
124
Which immunoglobulin does not cross the placenta from dam to fetus in any species?
IgM
125
Which immunoglobulin is found in body secretions?
IgA
126
elimination of virus infected cells; mediated by T-lymphocytes, macrophages, neutrophils, and cytokines
cellular immune response
127
Which immunoglobulin is responsible for immunity against reinfection?
IgG
128
Which immunoglobulin is important resistance to infection of the respiratory, intestinal, and urogenital tracts?
IgA
129
What happens when an immune system goes wrong?
causes tissue damage in vital organs, virus evades the immune system and establishes a persistent infection
130
A variety of cell types which carry antigen in a form that can stimulate lymphocytes
antigen presenting cells
131
list the types of antigen presenting cells:
macrophages, monocytes, dendritic cells
132
A genetic locus encoding class I and II proteins
MHC
133
Where are class I glycoproteins (MHC) found?
plasma membrane of most types of cells
134
Where are class II glycoproteins (MHC) found?
confined principally to APCs
135
Which immunoglobulin is able to cross the placenta?
IgG
136
What is the most important form of transfer for domestic animals?
postnatal (colostrum)
137
Replicates in the host, induces a lasting immune response without causing disease, produces a subclinical infection
live-virus vaccines
138
Vx administration routes (6):
SQ, IM, oral, aerosol, eye drops, water
139
goes through serial passage through cell cultures, laboratory animals, or embryonic eggs; temp-sensitive
attenuated live vaccines
140
uses viruses as vectors to carry the genes for the protective antigens or other viruses
virus-vectored vaccines
141
made from virulent virus and use chemical or physical agents to destroy infectivity while maintaining immunogenicity
inactivated vx
142
produces large amounts of viral protein by recombinant DNA technology
virus subunit vx
143
Most DNA viruses replicate in the:
cell nucleus
144
Most RNA viruses replicate in the:
cytoplasm
145
cells without receptors are not susceptible to:
viral attachment
146
What is the only type of virus that can do fusion penetration?
enveloped
147
entry by fusing with the plasma membrane
fusion
148
entry by endosomes at the cell surface (invagination of clathrin-coated pits into endosomes)
endocytosis
149
all proteins in a mature virus particles even if they make no contribution to the morphology or rigidity of the virion
structural protein
150
viral proteins found in the cell but not packaged into the virion
non-structural protein
151
morphological changes in the host cells caused by viruses
cytopathic effect
152
What is the use of cytopathic effect (CPE)?
identify the virus isolate
153
the first in vitro cultures of cells taken directly from the organs
primary culture
154
a cell line that can be subcultured and grown continuously
cell line
155
Which type of virus is more stable: DNA or RNA?
DNA
