Unit 1 - Virology Intro Flashcards Preview

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Flashcards in Unit 1 - Virology Intro Deck (155):
1

What year did Edward Jenner use cowpox from a milkmaid to vaccinate an 8 year old?

May 14 1796

2

What year was small pox eradicated?

1980

3

What year was HIV defined as the cause of AIDS?

1983

4

What year did David Baltimore and Howard Temin discover reverse transcriptase and retroviruses?

1970

5

What is one thing host cells can never replicate from viruses?

RNA

6

Negative Sense =

non-coding

7

An older term for AR-thropod BO-rne virus. Includes the Bunyaviridae, Togaviridae, some Orbiviruses, and Rhabdoviruses.

Arbovirus

8

a virus parasitizing bacterium; bacterium + to eat

bacteriophage

9

the protein coat of a virus

capsid

10

individual structural proteins that collectively make up the capsid

capsomeres

11

a virus particle having a capsid, but an incomplete nucleic acid content, or and empty particle, which interferes with replication of complete particles

defective interfering particle

12

the phospholipid covering derived from host cell membranes, either nuclear or cytoplasmic (plasma membrane or endoplasmic reticulum) present on some viruses

envelope

13

a polyhedral shape composed of 12 vertices (corners) and 20 triangular faces; cubic symmetry

icosahedron

14

a structural term denoting the combined nucleic acid and capsid; may be helical or cubic in symmetry

nucleocapsid

15

a virus isolated in the absence of disease

orphan virus

16

a gylcoprotein subunit projecting from the enveloped referred to as "spikes" that function in attachment to host cells

peplomere

17

unconventional agents of disease resulting in spongiform encephalopathies by proteins that cause protein folding anomalies.

prions

18

the process by which base sequences in mRNA produce specific amino-acid sequences in a protein

translation

19

the process of forming mRNA from nucleic acid, no necessarily DNA

transcription

20

an individual viral particle

virion

21

a class of infectious agents, ocurring in plants that are smaller than viruses and consist of short strands of RNA without a capsid

viroids

22

complex molecular particle, capable of infecting cells and causing disease by redirecting host cellular synthetic machinery towards the synthesis of new infectious particles

virus

23

Where do most DNA viruses replicate? RNA viruses?

cell nucleus; cytoplasm

24

What are the six steps of the replication cycle?

1. Attachment
2. Penetration
3. Uncoating
4. Synthesis
5. Assembly/Maturation
6. 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