Midterm Flashcards
(121 cards)
1
Q
What characteristics are considered in classifying viruses?
A
host range, virion morphology, nucleic acid type, specific genes, phylogenetic groupings
2
Q
What is the suffix for phylogenetic order?
A
ales (virales)
3
Q
What is the suffic for subfamily?
A
inae (virinae)
4
Q
What is the suffix for genus?
A
virus
5
Q
What are the steps in viral replication known as the “eclipse” phase?
A
uncoating –> assembly
6
Q
Which viral families an replicate in either the cytoplasm or nucleus?
A
retroviruses, hepadnaviruses
7
Q
Which types of viruses replicate in the nucleus?
A
most DNA viruses and orthomyxo (exception: pox)
8
Q
What types of viruses replicate in cytoplasm?
A
most RNA viruses and pox
9
Q
What two virus families have a ssDNA genome and replicate using host DNA replication system?
A
circo and parvo
10
Q
What are the two important RNA dependent RNA polymerases? What do they do?
A
replicase - copies viral RNA to produce progeny genomes
transcriptase - produces mRNA
11
Q
What kind of replication system is retroviruses?
A
SS + RNA with DNA intermediate (integrates into host genome)
12
Q
What are the 3 enzymatic activities of reverse transcriptase?
A
- RNA dependent DNA polymerase
- RNase H activity (degrades RNA from RNA/DNA hybrids)
- DNA dependent DNA polymerase
13
Q
What step is required right before a virion becomes infectious?
A
cleaving Gag and Gag/Pol polyproteins
14
Q
What is the definition of a quasispecies?
A
source of phenotypic variants that can rapidly respond to selective pressures by shifting population composition
15
Q
What are the 4 determinants of tissue tropism?
A
susceptibility, permissivity, accessibility, defense
16
Q
What are the 3 main functions of Type 1 interferons?
A
resistance to viral replication
increase MHC class 1 and antigen presentation
activate NK cells
17
Q
How does the virus entering cell turn on the antiviral response?
A
TLRs –> IFNs –>ISGs –> Antiviral response
18
Q
What cell types do DNA viruses “transform”?
A
primary non-permissive
19
Q
What cell types do RNA viruses transform?
A
permissive or non-permissive
20
Q
What types of oncogenes are involved in DNA virus transformation?
A
unique early viral genes, essential for replication
21
Q
What types of oncogenes are involved in RNA virus transformation?
A
c-onc or homologue (v-onc), non essential for replication
22
Q
What is the MOA of transformation with DNA viruses?
A
inhibit stop signals, inactivates TSP
23
Q
What are the 2 MOA of transformation in RNA viruses?
A
activate go signals
- transduction : v-onc
- insertional mutagenesis: near c-onc
24
Q
How does the interaction of transformation differ between RNA and DNA viruses?
A
RNA = steady state productive
both can be non-productive or integration
25
What is the cell tropism for parvo?
crypt cells and myeloid system cells (panleukopenia)
26
What is the pantropic form of parvo in neonatal dogs and cats?
dogs - myocardium
| cats - cerebellum
27
What problems does parvo porcine virus cause?
infertility
| >30 days --> mummification
28
What does the DsDNA of circovirus code for? (genomic and cdna strand)
genomic strand --> replication enzymes
| CDNA strand --> encodes capsid
29
How does circovirus differ from parvo in assembly?
circo assemblies in cytoplasm
30
What is the cell tropism for circovirus?
lymph nodes
| respiratory tract
31
How is PCV2 transmitted?
vertical (other circos are horizontal)
32
What is needed for viral clearance of PCV2?
cell mediated immunity
33
What syndrome is caused by porcine circovirus type 2?
post weaning multisystemic wasting syndrome
34
What other virus can PCV2 be synergistic with?
porcine parvo
35
What are the non permissive cells in the skin?
undifferentiated --> dermal/basal
36
What are the permissive cells in the skin?
differentiated --> keratinizing layer
37
How does the papilloma virus get into daughter cells in the skin?
episome sits in basal cell and is transmitted to daughter cells
38
What causes equine sarcoids?
bovine papilloma virus 1 or 2
39
What is the MOA of amantidine and rimantidine?
ion channel locker -->penetration inhibitor (prevents influenza virus from uncoating)
40
What drug is a nucleoside analog?
acyclovir
41
What drug is a pyrophosphate analog?
foscarnet
42
What viruses may be affected by foscarnet?
some DNA and RNA viruses (herpes and retro)
43
What drug is a reverse transcriptase inhibitor?
AZT (zidovudine)
44
What are the 3 protease inhibitors?
ritonavir, saquinavir, indinavir
45
What is the MOA of protease inhibitors?
blocks polyprotease --> the gag-pol polyprotein processing of retroviruses
46
What is the MOA of oseltamivir andd zanamivir?
neuraminidase inhibitor --> alteration of particle aggregation and release (keeps virus from budding)
47
What are the virus characteristics for adenoviridae?
ds DNA, nonenveloped
48
What are the epitopes of adenovirus that determine species specificity?
pentamers (vertices of capsid)
49
What are the epitopes of adenovirus that determine genus host specificity?
hexamers
50
What is the significance of the fibers on an adenovirus?
epitopes for antigens and help in initial attachment onto host cell
51
What 3 systems do adenoviruses have tropism to?
epithelial --> especially respiratory, enteric, and kidney
52
What is the incubation period of adenoviruses?
long - weeks
53
What is the overall pathogenesis of adenoviruses?
remains localized
54
Where does the adenovirus persist in the host animal?
pharyngeal or gut associated lymphoid tissue
55
What is the definition of ubiquitous in relation to viruses?
highly species specific
56
What adenovirus is an exception to the localized infection rule?
canine adeno 1 (infectios canine hepatitis)
57
What CS are there in the hepatic form of canine adenovirus 1?
hepatocellular destruction, hemorrhages, encephalitis
58
What 2 immune complex dzs are caused by CADV1?
arthus rxn - glomerulonephritis and blue eye
59
What dz does CADV2 cause?
tracheobronchitis, mild
60
What dz does equine adenovirus cause?
mild respiratory - bad in SCID foals
61
What is the problem with vaccines to adenoviruses?
too many serotypes (except CAdV)
62
What should you think when you hear poxvirus?
skin lesions and zoonotic potential
63
What are the characteristics of the poxviridae family?
ds DNA, complex virion, very big, can be enveloped or non-enveloped
64
What are the two morphological forms of pox viruses?
brick shaped - most
| ovoid - parapoxvirus
65
Where does poxvirus replicate?
cytoplasm (exception to DNA rule)
66
What is the cell tropism of pox?
epithelial cells (permissive)
67
What are the 2 forms of pathogenesis of pox?
localized infection - skin
| systemic by respiratory inhalation - skin and organ lesions
68
What is the incubation period for pox?
short
69
What are the 3 ways of transmission of pox?
skin abrasions, respiratory, mechanical vectors (NO vertical)
70
What two important viruses are in the orthopoxvirus subfamily?
smallpox, cowpox,
71
What is the resevoir for cowpox?
rodents
72
What is the diff dx of cowpox?
bovine mammilitis (BHV-2)
73
What are the 2 important viruses in the parapoxvirus subfamily?
orf, pseudocowpox
74
What are the CS of orf in lambs and kids?
severe oral lesions, high mortality
75
What are the CS of orf in adult sheep?
localized - eyelids, feet, teats,
| generalized skin lesions
76
What does pseudocowpox cause in humans?
milkders nodules
77
What are the CS of pseudocowpox in cows?
localized infection - teats, mouths of calves, ring or horseshoe scab
78
What are the two forms of fowlpox virus?
```
skin (dry form)
mucous membrane (wet) - systemic, diphtheritic, high mortality
```
79
What are the viral characteristics for asfaviridae?
ds DNA, enveloped (but stable in cold environment)
80
What is the tropism for asfaviridae?
lymphoreticular tissues - primary macrophages and monocytes so systemic infection is possible
81
How is asfaviridae transmitted (4 ways)?
respiratory (primary)
arbovirus (tick)
oral
reservoir
82
What is the pathogenesis of hemorrhage in asfaviridae?
apoptosis of lymphocytes -> endothelial damage ->DIC -> hemorrhage
83
What is the incubation period of asfaviridae?
5-15 days, varies
84
What causes hypergammaglobulinemia in asfaviridae infection?
high titers of non neutralizing antibodies that doesnt confer protection against virus
85
What is the acute form of ASF in swine?
fatal febrile hemorrhagic dz
86
What happens to swine that survive ASF?
persistently infected
87
What is the differential diagnosis for ASF?
classical swine fever (hog cholera)
88
What is the method of control for ASF?
rapid dianostics - slaughter, quarantine
no effective vax
disinfectants
89
What are the characteristics of herpes?
ds DNA, enveloped, large
90
What 7 important viruses are in the alphaherpes subfamily?
avian infectious laryngotracheitis, mareks dz, IBR, EHV 1 and 4, feline rhinotracheitis, pseudorabies
91
What is the host range for alpha, beta, and gamma herpes?
alpha - variable animal host range
beta - host specific
gamma - restricted host range
92
What does beta herpes cause in cells?
cytomegalia
93
Where do latent infections stay in beta herpes? (3)
secretory glands, lymphoreticular tissue, kidneys
94
Where do latent infections stay in gamma herpes?
lymphoid tissue
95
What disorders do gamma herpes cause?
lymphoproliferative disorders
96
How does herpes exit the cell from the nucleus?
buds thru nucleus -> ER cisternae -> exocytosis or cytolysis
97
What are the 4 different outcomes for viral-cell interations for all herpes viruses?
cytolysis
syncytia formation
latency - natural host
transformation
98
What is the MOA for latency in herpes virus?
episome reactivates - usually sublinical
99
What is the cell tropism for alpha herpes?
pneumotrophic and neurotropic (TQ)
100
What can a localized infection of a virus produce in the fetus?
systemic dz
101
How is herpes transmitted?
horizontal - close contact, lactogenic and blood
| vertical - tranplacental - systemic
102
What causes infectious bovine rhinotracheitis?
BHV type 1
103
What 2 dzs does IBR cause?
red nose - abortions (systemic) (inhalation)
| genital dz by coitus (abortion rare)
104
What causes equine abortion virus?
EHV-1
105
What can cause equine herpesvirus myeloencephalopathy in adult horses?
EHV1 mutates - increased virulence - neuropathogenic
106
What virus causes equine rhinopneuomonitis?
EHV4
107
What are the ages and CS of equine rhinopneumonitis?
after weaning - acute resp dz
| adults - subclinical, sporadic abortion
108
What are the CS of feline rhinotracheatis in young kittens?
rhinotracheitis, stomatitis, ulcerative keratoconjunctivitis
109
What are the CS of feline herpes in adult cats?
latent infection
abortion 2nd to fever and toxemia
herpetic ulcerative dermatitis from stress
110
What disease causes "pump handle" respiration in young chickens?
avian infectious laryngotracheitis
111
What are the permissive and semi permissive cells for mareks disease?
respiratory and feather follicle epithelium -- permissive
| lymphoblastic cells - semi-permissive
112
What is the end result of mareks dz pathogenesis?
polyneuritis (neural lymphomatosis = range paralysis)
113
What are gross lesions associated with mareks dz?
enlarged nerves, lymphoproliferation in various organs and skin
114
What are the 4 overlapping syndromes of mareks dz and what kind of dz do they cause? (acute, classical, ocular, cutaneous)
acute - respiratory
classical - neural lymphomatosis
ocular lymphomatosis - gray eye
cutaneous - lymphoproliferative skin form
115
What herpes virus is enzootic in feral pig population?
pseudorabies
116
What 2 diseases does pseudorabies cause in dead end hosts?
mad itch -> death
| pseudorabies -> death
117
What species are betaherpesviruses economically important for?
cattle, swine, horses
118
What are the resevoirs for bovine malignant catarrhal fever?
sheep, zoos, wild deer
119
What is the cell tropism for bovine malignant catarrhal fever?
lymphoid tissue - > viremia --> latency
| epithelial cells - resp and GI
120
What are the two primary clinical features of bovine malignant catarrhal fever
peripheral corneal opacity
| profuse nasal and ocular discharge and diarrhea
121
Which subfamily of herpes viruses has continuous shedding?
gamma
