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446- ID and transplant > Introduction to Virology > Flashcards

Introduction to Virology Flashcards

1
Q

viruses are a ____ complex that infect cells

A

nucleoprotein

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2
Q

viruses are metabolically

A

inert

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3
Q

which is false about viruses
1. DNA viruses assemble in cytoplasm
2. mostly highly species specific
3. are metabolically inert
4. virion is the whole spreadable particle

A

1- nucleus

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4
Q

what is the nucleocapsid

A

genome + capsid

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5
Q

capsomere functions

A

helps define shape of capsid

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6
Q

viral envelopes are
1. host
2. virus
3. both host and virus
4. made from capsomeres

A

1

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7
Q

Viruses with similar structural, henomic, and replication properties are grouped into __________ (ex- suffix_________)

A

families
-viridae

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8
Q

families are sudivided into ____

A

genera

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9
Q

virus subtypes are based on

A

nucleotide sequence and antigenic reactivities

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10
Q

viral capsid forms include

A

helical
icosahedral
complex

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11
Q

basic viral envelope forms include

A

icosahedral nonenveloped
icosahedral enveloped

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12
Q

the viral envelope is involved in (4)

A

attachment, entry, assembly, release

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13
Q

envelope proteins are ___, lipids are ______

A

viral
host

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14
Q

T or F: if membrane envelope is destroyed, the virus infects all cells in its proximity by direct benetration

A

F- virus becomes noninfectious

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15
Q

3 forms of adsorption/ attachment

A

direct penetration
fusion
endocytosis

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16
Q

describe direct penetration with viral attachment

A

Usually nonenveloped virus penetrating host cell through receptors on side of plasma membrane = release virus directly into host cell
Capsid is left behind

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17
Q

describe fusion with viral attachment

A

only with enveloped viruses. Viral glycoproteins bind receptors of host cell = fuse envelope with membrane and releases viral capsid inside host cell

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18
Q

describe endocytosis with viral attachment

A

Host cell engulfs virus, capsid, and envelope all together- host cell mem, envelope, and capsid all disintegrate inside host cell

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19
Q

describe uncoating

A

removing all or part of viral capsid
viral genome is accessible to host cell’s transcription and translation machinery

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20
Q

DNA viruses replicate in

A

host cell nucleus mediated by viral enzymes

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21
Q

T or F: viruses come with some of their own enzymes to reproduce within host cell

A

T

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22
Q

T or F: all portions of DNA virus are replicated in host cell cytoplasm

A

F- only DNA in nucleus, rest are in cytoplasm

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23
Q

which virus is the exception to the DNA virus replication rule

A

poxvirus- DNA but synthesize in cytoplasm

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24
Q

____ type RNA acts as mRNA

A

+

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25
viral proteins with RNA viruses are made in
cytoplasm
26
T or F: naked RNA nucleic acid is infectious
T
27
neg sense RNA must first ___________________ before it can replicate
make a + sense RNA/ mRNA
28
viral capsomers _______ assemble into crystal like arrays
self
29
describe the 3 points of viral assembly
Replication of viral genome and synthesis of proteins are complete Viral capsomers self assemble into crystal like arrays Newly formed capsid is filled with viral nucleic acid and buds out
30
enveloped viruses are typically released by
budding
31
is budding always lethal to the host cell?
not always, sometimes
32
how are nonenveloped virions released
when the cell lysis
33
After encountering a host cell, the virus must (3)
Enter the cells Undergo a period of primary replication Spread to its final target tissue- infect and successfully replicate in a susceptible population of host cells
34
3 types of viral infections
lytic latent chronic
35
describe a lytic infection
Multiple rounds of replication results in death of the host cell (virus factory) Polio, influenza
36
describe a latent infection
No immediate production of progeny virus Viral nucleic acid carried as extrachromosomal element or an integrated sequence in the host cell DNA
37
in latent infections, the viral nucleic acid is carried as an ___________ or __________
extrachromosomal element integrated sequence in host cell DNA
38
describe a chronic viral infection
Virus particles continue to shed after the period of acute illness has passed slow release of virus particles without death of host cell
39
4 types of virus host cell interaction
lytic cell transformation latent/ occult cell fusion to form multinucleated cells
40
respiratory route of transmission involves
Aerosol droplets, nasal secretions, or saliva via coughing or sneezing
41
common cold is spread by
aerosols and fomites
42
GI route of viral infection is from
viral shed in feces- contaminate food or water - ingested by susceptible individual stool tainted hands, poor hygeine
43
transcutaneous route of infection involves
Direct inoculation via insect, animal bites or mech devices like needles
44
west nile is spread
transcutaneously
45
why are humans a dead end for west nile
do not develop high levels of virus in bloodstream = can’t pass virus on to other biting mosquitos
46
iatrogenic transcutaneous infections are induced by
medical or diagnostic procedures- contaminated blood products, infected donor material, purposeful as vaccination, etc
47
sexual transmission of viruses may see the virus spread to
to other parts of the body or remain near the site of entry
48
horizontal sexual transmission is between
between members of a susceptible host population
49
vertical sexual transmission is
infection of fetus in utero through virus carried in germ line or infecting the placenta or in the birth canal
50
T or F: viruses may stay at the same site or spread to other area to produce disease
T
51
which has no role in primary response or acute viral infections 1. complement 2. cell mediated immunity 3. antibody response 4. 3+4
3
52
antibody response is very important in ______________. neutralizing antibodies reduce effectiveness by _________, _____, _______
preventing reinfections inhibiting attachment, penetration, or uncoating of virus
53
viruses can trigger the activation of the ___ and _______ pathways of complement
alternate classic
54
virus activated complement enhances _________ = _____________
phagocytosis of viruses = lysis of enveloped virus or virus infected cells
55
what happens in cell mediated immunity
infected cells are susceptible to the action of lymphocytes that recognize viral antigens on their surface = can be lysed
56
CPE applies to
virus induced cellular changes that are visible by light microscope
57
the most effective way to visualize viral changes to cells is by
staining cells with chromatic dyes
58
what is the basic and acidic dye in CPE
basic = hematoxylin acidic = eosin
59
direct detection fluorescent antigen is used for
viruses that create lesions
60
how to prep sample for direct fluorescent antigen observation under UV microscope
Vigorous scraping of lesion base is essential- remove scab before sampling
61
dierct detection fluorescent antigen uses _______________________ for detection
Uses HSV antigen specific murine MAbs (fluorescein labeled) for detection
62
Direct detection fluorescent antigen is observed under
UV microscope
63
pros of viral culture
Can differentiate between viable and non-viable viral particles Able to detect unknown viral etiologies Inexpensive compared to PCR
64
cons of viral culture
Relatively slow Does not support growth for all types of viruses Toxins can resemble cytopathic effects = false + Contamination due to bacteria, fungus and mycoplasma reduce the sensitivity of viral detection Endogenous virus from cells can be mistaken as the infectious agent
65
_________: fourfold or greater increase in antibody titre to spec viral agent in acute and convalescent sera (3-4wks later)
serology
66
IgM antibody is a marker of
current/ acute rxn
67
IgG is a marker of
past infection in the last 3-4weeks
68
molecular studies are the
detection of even single copies of virus genome in tissues or cells from body fluids
69
molecular studies utilize _____ which may be visualized by ____ or _________
PCR gel electrophoresis real time by computer
70
pros of viral amplification
Can detect v low number of viruses Rapid High throughput Multiplexed assays
71
cons of viral replication
Contamination due to high conc of amplicons Detection of dead organisms False + and false - results Expensive Special training

446- ID and transplant (18 decks)

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