Virology Midterm 1 - Fall 2Nd Year

Front 1

What are the DNA viruses in the baltimore classification?

Back 1

dsDNA
ssDNA(+)
gapped circular dsDNA

Front 2

What are the RNA viruses in the baltimore classification?

Back 2

dsRNA
ssRNA(+)
ssRNA(-)
ssRNA(+) reverse transcribing viruses

Front 3

Where do most DNA viruses replicate inside the cells?

Back 3

nucleus

Front 4

Where do most RNA viruses replicate inside the cells?

Back 4

cytoplasm

Front 5

What are the steps in virus replication?

Back 5

Virus attachment and entry
Genome replication
Virus assembly
Virus exit/maturation

Front 6

What are some general cellular structures that viruses attach to?

Back 6

Glycoproteins
Carbohydrate residues

Front 7

The type of cell within a host that a virus can infect is referred to as the virus ____________.

Back 7

tropism

Front 8

There are three ways that the virus can cross the outer cell membrane to infect a host cell. What are they?

Back 8

Translocation
Endocytosis
Membrane fusion
(I guess also injection in the case of bacteriophages)

Front 9

The release of the viral nucleic acid from its protective coat is known as ______________.

Back 9

uncoating

Front 10

What are methods of uncoating discussed?

Back 10

Uncoating at plasma membrane
Uncoating within endosomes
Uncoating at nuclear membrane

Front 11

What part of the virus binds to the host receptor?

Back 11

protein capsid or glycoprotein on envelope

Front 12

Which parts of the virus need to be reproduced to produce the virion?

Back 12

genome and capsid

Front 13

What are some example dsDNA viruses?

Back 13

Polymaviridae, Adenoviridae, Herpesviridae, poxviridae

Front 14

What are some example ssDNA viruses?

Back 14

Circoviridae, parvoviridae

Front 15

What are some example viruses of the dsRNA genome?

Back 15

Reoviridae

Front 16

What are some example viruses of the ss (-) RNA genome?

Back 16

Orthomyxoviridae, paramyxoviridae, Rhabdoviridae

Front 17

What are some example viruses of the ss (+) RNA genome?

Back 17

Retroviridae (uses reverse transcriptase; DNA intermediate)
Coronaviridae, Flaviviridae, Picornaviridae (no DNA intermediate)

Front 18

What are some example viruses of the gapped, circular, dsDNA genome?

Back 18

Hepadnaviridae

Front 19

T or F:
Viruses with an unsegmented genome tend to translate their proteins from a monocistronic mRNA.

Back 19

False!
This describes viruses with a segmented genome.

Front 20

T or F:
Monocistronic describes the translation of a protein into one huge piece that is subsequently broken into smaller proteins.

Back 20

False!
This describes polycistronic.

Front 21

What proteins are encoded by the viral genome?

Back 21

Structural proteins (gag)
Polymerase proteins (pol)

Front 22

Which protein is critical for negative ssRNA virus replication?

Back 22

RNA dependent RNA polymerase

Front 23

Which protein is critical for positive ssRNA virus replication?

Back 23

RNA dependent DNA polymerase

Front 24

Which viruses assemble in the cytoplasm?

Back 24

Picornaviruses, Poxviruses, Reoviruses

Front 25

Which viruses assemble in the nucleus?

Back 25

Adenoviruses, Papovaviruses, Parvoviruses

Front 26

Which viruses assemble at the cell membrane?

Back 26

Retroviruses

Front 27

What are the building blocks of the capsid?

Back 27

protomers assembled into pentamers (these are the capsid subunits)

Front 28

What is the stage of the viral cycle when the viron becomes infectious?

Back 28

maturation and exit

Front 29

How do non-enveloped viruses escape the cell?

Back 29

lysis

Front 30

How do enveloped viruses escape the cell?

Back 30

uses budding to "steal" some of the cell membrane

Front 31

What enzyme breaks the viral bond to the cell membrane?

Back 31

neuraminidase

Front 32

What is the interval between viral attachment and the appearance of infectious viral particles?

Back 32

Latency

Front 33

What are Koch's postulates for viruses?

Back 33

1. agent must be present in every case of dz.
2. agent must be isolated from host and grown in vitro
3. dz reproduced when pure culture is inoculated into healthy animal
4. same agent must be recovered from infected animal
5. agent must pass through ceramic filter that would retain smallest bacteria

Front 34

What is the range of sizes for viruses?

Back 34

20 to 300nm

Front 35

single-stranded RNA molecules
that lack genes required for their replication are known as...

Back 35

...virusoids/satellites

Front 36

An infectious protein is a(n)...

Back 36

...prion

Front 37

What components comprise the virion?

Back 37

genome
capsid
+/- envelope

Front 38

What is the basic capsid structure of a virus?

Back 38

icosahedron

Front 39

How are viruses classified today?

Back 39

Host
Morphology
Genome
Replication

Front 40

A group of species sharing common characteristics is a(n)... and taxonomic suffix

Back 40

genus; -virus

Front 41

A group of genera sharing close phylogenetic relationship is a(n)... and its taxonomic suffix

Back 41

family; -viridae

Front 42

What are the best type of cells for virus isolation?

Back 42

Primary cell cultures

Front 43

A cell culture that can exist indefinitely is a(n) ___________________.

Back 43

cell line

Front 44

T or F:
Both primary and secondary cell cultures are explanted from a donor organism.

Back 44

True

Front 45

T or F:
Due to their immortality, cell lines are considered cancer or tumor cells.

Back 45

False!
Some are cancer or tumor cells but not all.

Front 46

What are the types of viral infections possible in a host?

Back 46

Acute (<2wks)
Persistent
Latent

Front 47

What effects on the cell can viral infection incur?

Back 47

No effect
Cytopathology
Malignant transformation
Cell death

Front 48

T or F:
Cytopathic effects cannot be viewed via light microscopy.

Back 48

False! They CAN be viewed with light microscopy

Front 49

What are the cytopathic effects?

Back 49

Altered shape
Detachment from substrate
Lysis
Membrane fusion
Syncytia
Inclusion body
Apoptosis
Altered membrane permeability
Cytoskeleton change

Front 50

Which viruses cause the CPE syncytia?

Back 50

(i) Lentivirus
(ii) Paramyxoviruses
(iii) Morbilliviruses
(iv) Pneumoviruses
(v) Some herpesvirus

Front 51

Where and/or how can some inclusion bodies be found?

Back 51

Cytoplasmic/nuclear
single/multiple
large/small
round/irregular
basophilic/acidophilic

Front 52

What are some viruses that cause inclusion body CPEs?

Back 52

(i) Poxvirus
(ii) Reovirus
(iii) Paramyxoviruses
(iv) Rabies virus
(v) Herpesvirus
(vi) Adenovirus
(vii) Parvovirus

Front 53

What are some viruses that cause apopotsis CPEs?

Back 53

(a) Adenoviruses
(b) Alphaviruses
(c) Chicken anemia virus
(d) FIV
(e) Herpesvirus

Front 54

What are some viruses that can cause cytoskeletal change CPEs?

Back 54

(i) Canine distemper virus
(ii) Vesicular stomatitis viruse
(iii) Vaccinia virus
(iv) Herpesvirus
(v) Enterovirus

Front 55

What are some mechanisms of viral damage to the host cell?

Back 55

1) Inhibition of host cell nucleic acid synthesis (DNA and RNA)
2) RNA transcription inhibition.
3) inhibit mRNA processing
4) inhibit protein translation
5) cytopathic effects of viral toxins

Front 56

The incorporation of viral glycoprotein peplomers into the plasma membrane of infected cells where they serve as ligands for RBCs is called...

Back 56

...hemadsorption

Front 57

What are some viruses that exhibit hemadsorption?

Back 57

(a) Orthomyxovirus
(b) Paramyxovirus
(c) Togavirus
(d) calicivirus

Front 58

T or F:
Noncytocidal viruses rarely cause cell death.

Back 58

duh...true

Front 59

What are some examples of virus-induced noncytocidal change?

Back 59

behavior change
delayed growth
hyperglycemia

Front 60

T or F:
The vast majority of virus infections are sub-clinical, i.e. asymptomatic!

Back 60

True

Front 61

Which viruses have a selective tropism for the skin?

Back 61

Papillomaviruses

Front 62

What are routes of viral infection?

Back 62

Skin
Eyes
Respiratory mucosa
GI (including mouth)
Urogenital tract

Front 63

Which viruses commonly enter through the GI tract? Why/how can they do this?

Back 63

Enteroviruses
Acid resistant

Front 64

T or F:
Hepatitis A and B both function epidemiologically as an enterovirus.

Back 64

False! This describes A not B.

Front 65

What are some viruses that commonly use the urogenital tract as a port of entry?

Back 65

(b) Papillomaviruses
(c) HSV
(d) Hepatitis
(e) HIV

Front 66

Which viruses use the eye as a common port of entry?

Back 66

Adenovirus: “swimming pool conjunctivitis” and “shipyard eye”
Enterovirus: coxsackievirus A24 and enterovirus type 70
Vaccinia and HSV

Front 67

Which viral group is transmitted by an insect vector?

Back 67

Arbovirus

Front 68

Which virus is only transmitted via the bite of a host?

Back 68

Rabies virus

Front 69

How does local virus spread occur?

Back 69

cell to cell

Front 70

Viruses that are released on the apical edge of the cell spread __________ while viruses released on the basal edge spread __________.

Back 70

locally; systemically

Front 71

Viruses that are released on the _________ edge of the cell spread locally while viruses released on the _________ edge spread systemically.

Back 71

apical; basal

Front 72

How does systemic virus spread occur?

Back 72

afferent lymph drainage to regional lymph nodes then to lymph ducts
via bloodstream
via nervous system

Front 73

What are some viruses that spread neurally?

Back 73

Polio (piconaviridae)
rabies (rhabdoviridae)
bovine herpesvirus 1 and 2

Front 74

Viruses circulating in the blood plasma or associated with formed blood elements is known as _______.

Back 74

viremia

Front 75

What are the three types of viremia (maybe stages of viremia)?

Back 75

Active
Primary
Secondary

Front 76

The type of viremia that is not associated with any formed blood elements is __________ viremia.

Back 76

plasma

Front 77

If the virus is within circulating blood cells, it is called _______________ viremia.

Back 77

cell-associated

Front 78

Where can virus enter the circulation?

Back 78

efferent lymphatics
vascular endothelium
peripheral monocytic cells

Front 79

Release of the virus by the host into the environment is known as ____________.

Back 79

shedding

Front 80

What are some viruses shed by oral secretion?

Back 80

BHV-1, paramyxo-, corona-, and bovine respiratory syncytial virus

Front 81

What are some viruses shed via the skin?

Back 81

Cowpox, vaccinia, orf, pseudocowpox, molluscum contagiosum viruse, papillomaviruses, herpesvirus, Mareck's dz virus

Front 82

What are some viruses shed form the urinary tract?

Back 82

Rinderpest virus, Flu viruses, Picornaviruses, hepatitiss virus, FMDV, arenaviruses,

Front 83

What are some viruses shed via the genital tract?

Back 83

(a) Equine arteritis
(b) Herpesvirus
(c) Papillomavirus

Front 84

What does “infectious” mean?

Back 84

Ability to transmit disease to other organisms

Front 85

Why is a virus infectious?

Back 85

transmissible

Front 86

Which viruses are shed via milk?

Back 86

(a) Caprine arthritis-encephalitis virus
(b) Mouse mammary tumor virus
(c) Tick-borne flaviviruses

Front 87

Which viruses are shed via blood?

Back 87

(a) Equine infectious anemia virus
(b) Bovine leukemia virus

Front 88

Which organs are responsible for viral clearance?

Back 88

Liver, lung, spleen, and lymph nodes

Front 89

What is the role of DNA-dependent RNA polymerase (DRP) in the eukaryotic cell?

Back 89

- Transcribes RNA from DNA template
in eukaryotic cells, DRPI direct synthesis of ribosomal RNAs, mRNA, and tRNAs

Front 90

What is the term for the measure of the pathogenicity of the infecting virus?

Back 90

Virulence

Front 91

What does LD50 measure?

Back 91

Dose of virus required to cause death in 50% of individuals

Front 92

What does ID50 measure?

Back 92

dose of virus required to cause infection in 50% of individuals

Front 93

What does TCID50 measure?

Back 93

infectious dose that causes cytopathic effect in 50% of individuals

Front 94

T or F:
The humoral and cell mediated immune response both kill virus infected cells.

Back 94

False.
Only the cell-mediated pathway kills intercellularly.

Front 95

What is bad about a non-neutralizing antibody in viral infection?

Back 95

Non-neutralizing antibody only opsonizes the virus but does not inactivate it; allows for viral spread via phagocytes

Front 96

Are virus-infected cells killed via the CD4/MHCII path or the CD8/MHC1 path?

Back 96

CD8/MHC1

Front 97

What are the 8 types of viral vaccine?

Back 97

Live whole virus vaccines
Killed whole virus vaccines
Subunit vaccines
Recombinant virus vaccines
Synthetic peptides
Anti-idiotype antibodies
DNA vaccines
Peptide vaccine

Front 98

When should puppies be vaccinated against rabies?

Back 98

@ 16 weeks

Front 99

When should kittens be vaccinated against rabies?

Back 99

12 weeks

Front 100

When should foals/livestock be vaccinated?

Back 100

no earlier than 3-4mos then 4 week intervals

Front 101

T or F:
Live vaccines should always be used for intraoral or intranasal vaccines.

Back 101

True!

Front 102

Why should you not give a "booster" for a mucosal vaccine?

Back 102

Secondary immune responses are difficult to elicit.
High IgA levels prevent antigen absorption.

Front 103

Which virus typically does the most damage: RNA or DNA virus?

Back 103

DNA virus (herpes and pox)

Front 104

What are the basic evasion mechanisms of viruses?

Back 104

Passive (innocuous)
Active (produce proteins that affect immune system)
Aggressive (directly target immune system)

Front 105

What are some passive evasion mechanisms of viruses?

Back 105

Evasion by noncytocidal infxn
evasion by cell-to-cell spread (masks from immune system)
evasion via infxn of nonpermissive cells
Restricted viral gene expression

Front 106

What are some active viral evasion mechanisms?

Back 106

Evasion of neutralizing Ab (immune decoys)
Interfere w/antigen processing
Complement evasion
Inhibit interferons

Front 107

What are some aggressive viral evasion mechanisms?

Back 107

Immunosuppression by targeting leukocytes
Use virokines

Front 108

A viral product that suppresses or inhibits cytokines is a(n) ___________.

Back 108

virokine

Front 109

What is the common feature for a virus family?

A. Same host
B. Same genome type
C. Same morphology
D. Same replication strategy
E. ABC
F. BCD

Back 109

F. BCD

Front 110

What is the suffix for a virus family?

A. Virale
B. Viridae
C. Virinae
D. Virus

Back 110

B. Viridae

Front 111

What is the suffix for a virus subfamily
A. Virale
B. Virdae
C. Virinae
D. Virus

Back 111

C. Virinae

Front 112

How does virus get into cells?
A. Special passport
B. Poke a hole
C. Endocytosis
D. Translocation, fusion
E. A, C
F. C, D

Back 112

F. C, D

Front 113

What are the essential component that –ssRNA virions must carry before infecting a cell?
A. Passport
B. RNA genome
C. RNA dependent RNA poly
D. B and C
E. Envelope

Back 113

D. B and C

Front 114

Name some factors that influence viral susceptibility...

Back 114

1) Genetic constitution
2) Immune response (Overreaction of immune response usually)
3) Cell differentiation
4) Cellular receptor
5) Age
6) Hormonal factors
7) Fever
8) Multiple infection

Front 115

Is the virus stable at room temperature?

Back 115

nope

Front 116

Is virus stable at pH extremes?

Back 116

not generally (I guess enterovirus is)

Front 117

How much sample is needed for virus diagnosis?

Back 117

~5mL (1-2mL)

Front 118

What are the methods of virus DETECTION?

Back 118

via electron microscopy
virus isolation in cultured cells
virus isolation in animals/chick embryos

Front 119

What are some methods of direct detection and identification of viral nucleic acids?

Back 119

Hybridization (in situ, southern, dot-blots)
PCR (RT, real time, and semi quant)

Front 120

What are some diagnostic methods for identifying a virus?

Back 120

1) Detection and ID of viral antigens
2) Direct detection and ID of viral nucleic acids
3) Virus isolation and identification
4) Detection and quantification of antiviral antibodies

Front 121

What are some tools available for detecting viral antigens?

Back 121

Elisa
Fluorescence antigen microscopy
IHC and immunofluorescence
immunoelectron microscopy
agglutination
immunodiffusion

Front 122

Serology detects the presence of the (choose one) antigen or antibody.

Back 122

Antibody!

Front 123

What did you see in cells infected w/BAV?

A. Enlarged nuc and nuc inclusion body
B. Cell lysis
C. Irregular cell morphology
D. All of the above

Back 123

D. All of the above

Front 124

What did you see in cells infected w/BVDV
A. Inclusion body in the nuc
B. Enlarged nuc
C. Inclusion body in the cytoplasm
D. Membrane fusion

Back 124

C. Inclusion body in the cytoplasm

Front 125

How do you isolate viruses from tissue collected from infected animal?

Back 125

Grind tissue
Freeze/thaw
Centrifuge; virus will be in supernatant
Put on cell line and culture!

Front 126

How big are circoviruses? What is their capsid morphology?

Back 126

17-22nm
Icosahedral

Front 127

Describe the genome of circoviruses?

Back 127

Circular, ssDNA genome
ORF1, ORF2, ORF3 – only 3 proteins

Front 128

PMWS (Porcine Multisystemic Wasting Syndrome) is caused by which virus?

Back 128

Circovirus (Porcine Cicrcovirus type 2)

Front 129

Which virus causes beak and feather disease?

Back 129

Circovirus

Front 130

What is the general pathology of a circovirus infection?

Back 130

young animals
Hemorrhage (subcut and muscle)
Pale viscera
Fatty bone marrow
Thymic atrophy

Front 131

What happens when RBCs are replaced by fat cells in bone marrow? Which virus is characterized by this pathology?

Back 131

Anemia; circovirus

Front 132

How does circovirus infection cause immunosuppression?

Back 132

monocyte/macrophage destruction

Front 133

What is the 2nd smallest DNA virus?

Back 133

Parvovirus

Front 134

What did you see in cells infected w/BVDV
A. Inclusion body in the nuc
B. Enlarged nuc
C. Inclusion body in the cytoplasm
D. Membrane fusion

Back 134

C. Inclusion body in the cytoplasm

Front 135

How do you isolate viruses from tissue collected from infected animal?

Back 135

Grind tissue
Freeze/thaw
Centrifuge; virus will be in supernatant
Put on cell line and culture!

Front 136

How big are circoviruses? What is their capsid morphology?

Back 136

17-22nm
Icosahedral

Front 137

Describe the genome of circoviruses?

Back 137

Circular, ssDNA genome
ORF1, ORF2, ORF3 – only 3 proteins

Front 138

PMWS (Porcine Multisystemic Wasting Syndrome) is caused by which virus?

Back 138

Circovirus (Porcine Cicrcovirus type 2)

Front 139

Which virus causes beak and feather disease?

Back 139

Circovirus

Front 140

What is the general pathology of a circovirus infection?

Back 140

young animals
Hemorrhage (subcut and muscle)
Pale viscera
Fatty bone marrow
Thymic atrophy

Front 141

What happens when RBCs are replaced by fat cells in bone marrow? Which virus is characterized by this pathology?

Back 141

Anemia; circovirus

Front 142

How does circovirus infection cause immunosuppression?

Back 142

monocyte/macrophage destruction

Front 143

What is the 2nd smallest DNA virus?

Back 143

Parvovirus (18-26nm)

Front 144

Which of the following is untrue regarding parvoviridae?
A. nonenveloped
B. icosohedral
C. 3 capsid proteins
4. pH resistant
5. sensitive to temperature extremes

Back 144

5. sensitive to temperature extremes

Front 145

Describe the genome of parvoviridae.

Back 145

i. Linear, non-seg
ii. 5.2kb ssDNA
iii. Palindromic ends

Front 146

T or F:
FPV (Feline Panleukopenia) is a type of parvovirus.

Back 146

True

Front 147

Describe the genome of adenoviridae.

Back 147

30-42kb
Linear, ds DNA

Front 148

What is major capsid protein for parvo?

Back 148

BP2

Front 149

Can parvo infect many different tissues in fetus and neonate?

Back 149

yup

Front 150

Why do we see cerebellar hypoplasia in newborn (with parvovirus infection)?

Back 150

growing cerebellar cells

Front 151

Why does parvovirus infection manifest in diarrhea?

Back 151

kills growing crypt cells

Front 152

What are the two main classes of antiviral drugs?

Back 152

Small molecules
Biologicals

Front 153

What are the subcategories of biological antiviral drugs?

Back 153

Antibodies
Peptides
siRNA
interferons

Front 154

Which mechanisms are targeted for antiviral activity? Which is specific to retroviruses?

Back 154

Binding and entry inhibition
Integration inhibitors (retrovirus)
Replication inhibitors
Egress inhibitors
Protease inhibitors

Front 155

What is the major mechanism of replication inhibition?

Back 155

chain termination during replication

Front 156

What are two mechanisms that viral entry inhibitors may use?

Back 156

mimics receptor of virus
mimics host target protein

Front 157

What type of cell line was used in lab to observe CPE?

Back 157

immortalized rabbit kidney cells (RK-13B)

Front 158

T or F:
The virus titer is the approximate number of pathogenic viral particles per mL of serum.

Back 158

True!

Front 159

What type of CPEs were observed on the BVDV?

Back 159

inclusion bodies in cytoplasm

Front 160

What type of CPEs were observed on ERV-1?

Back 160

inclusion bodies in cytoplasm and altered cell morphology

Front 161

What type of CPEs were observed in BHV-1 (IBR)?

Back 161

fusion

Front 162

What type of CPEs were observed on BAV?

Back 162

intranuclear occlusions; apoptotic bodies

Front 163

What is a virus?

Back 163

sub-microscopic, obligate intracellular parasites

Front 164

What is a viroid?

Back 164

Obligate intracellular parasite that replicated like a virus but has no capsid or envelope and genome is made of circular RNA molecules

Front 165

What is a morphologically complete virus particle, which is infectious, called?

Back 165

virion

Front 166

Taxonomic suffix for subfamily

Back 166

-virinae