Microbiology III Flashcards
1
Q
How does the cell produce an immune response toward virus?
A
Viral proteins cut up
Class I HLA presents
Cytotoxic T-cells destroy
Ab intercepts
2
Q
T/F
All known life has viruses
A
True
3
Q
What does a fast mutation of “spikes” mean?
A
Epitopes change and Antibody can’t recognize
4
Q
What are 4 possible genome categories for viruses?
A
dsDNA
dsRNA
ssDNA
ssRNA
5
Q
What surrounds the genetic material in a virus?
What shape is it?
A
capsid
icosahedral or helical
6
Q
After replicating, what are the 2 ways a virus leaves a cell?
A
Budding (envelope with spikes)
Lysis
7
Q
Lytic viruses are…
Non-lytic viruses are…
A
Naked
Enveloped
8
Q
A Latent virus, like Herpes, can be…
HPV cause cancer because they…
A
Latent
Transformation (hyperproliferation)
*hyperproliferation causes the cell to divide, thereby replicating the virus that is part of the genome
9
Q
Aside from being enveloped or non-enveloped, a virus can be…
A
Complex
characteristics of both
10
Q
Define sense and antisense:
A
sense (+): same as mRNA
antisense (-): same as template DNA
11
Q
What are the 4 structural possibilities for a virus?
A
Icosahedral (naked or enveloped)
Helical (naked or enveloped)
12
Q
plus(+) sense ssRNA viruses must bring what with it?
A
RNA-dependent RNA polymerase
makes template strand for ssRNA sequence for every replicated virus
- sense strand directly codes for proteins
- *type I virus
13
Q
anti-sense(-) ssRNA viruses must bring what with it?
A
RNA-dependent RNA polymerase
anti-sense(-) to sense(+)
- sense strand codes for proteins AND (-)ssRNA
- *type II virus
14
Q
Upon entering the cell, what does dsRNA need to replicate?
A
RNA-dependent RNA polymerase to make sense(+) strand from DNA template.
AND to make dsDNA from (+)sense strands
- sense strand makes mRNA’s and viral proteins
- *type III virus
15
Q
Describe the replication of Type IV (+)ssRNA.
A
sense strand enters
Viral RNA-dependent DNA polymerase creates (-)DNA
Viral RNA-dependent DNA polymerase creates (+)DNA
host cell integration
all host machinery from here
*aka Reverse Transcriptase
16
Q
T/F
RNA viruses need their own polymerase at some step, while DNA viruses do not.
A
True
17
Q
T/F
(+)ssRNA are the only viruses that don’t need to bring a polymerase with them into the cell.
A
True
they are already mRNA, so code for needed proteins
18
Q
What are viruses that lack capsids?
What do they infect?
A
Viroids
(free nucleic acids)
Infect only plants
19
Q
What are infectious proteins?
A
Prions
20
Q
Infections are spread:
Horizontally
Vertically
A
person to person
mother to neonate
21
Q
What is the low profile of an infectious agent called?
A
Iceberg effect
22
Q
What is required for a pathogen to have a big iceberg effect?
A
Many carriers (infectious, no symptoms)
23
Q
Name two diseases that exhibit large iceberg effects?
A
Polio (huge)
Measles
24
Q
How does antigen at one mucosal site stimulate antibody protection at all others?
A
IgA reacts with Ag at all sites
APC’s cause T and B to react and clone
Daughter B cells migrate to other mucosal sites
25
What receptor is integral in moving new IgA from B-emmigrant cells onto mucosal surface?
poly-lg Fc receptors
| takes off B cells
26
What protects sIgA dimers from proteases on the mucosal surface?
Where does this come from?
secretory component
protease that cleaved sIgA from poly-lg Fc receptor
27
How does sIgA protect neonates?
Through mother's milk
| Stays in intestinal lumen
28
What 2 places does a baby's passive immunity come from?
sIgA in gut through milk
| IgG through placental transfer
29
IgA found outside the body is _____, while IgA found inside the body is typically ______.
Dimeric
| Monomeric
30
T/F
| sIgA is a poor activator of Complement and an inconsistent opsonizer.
True
31
What does anergy refer to in oral tolerance?
| What is the main inhibitory cytokine involved?
High Ag feeding induces tolerance
| TGF-beta
32
What is the immunoglobulin complex that sticks to mucins?
What is this resistant to?
What does it block?
sIgA2
Proteases
Colonization
33
What are the specialized APC's found in the mucosa?
M-cells
34
What does sIgA stick to on mucosal surfaces?
mucins
35
What type of virus is Polio?
Picornavirus
36
Polio is enveloped/naked
is a (what stranded) RNA
usually found what part of body
Naked
(+)RNA
enterovirus
37
Where does Polio bind in the body and replicate?
Oropharynx/GI tract
38
How is Polio transmitted?
| What are its viremic effects?
Oro-fecally
| Neurotropic
39
What prevents initial colonization of the Polio virus?
| What prevents viremia?
sIgA
| IgG
40
What Polio vaccine is killed and induces IgG?
| Which one is attenuated-live and induces sIgA and IgG?
Salk
| Sabin
41
What are the Oro-Fecal considerations of the Polio vaccines?
Salk - 2 month window of continued fecal Polio excretion
Sabin - Fecal sIgA will confer bystander immunity
42
Even though it confers IgG, sIgA, and bystander immunity, what is a downside to the Sabin vaccine?
Can infect immunocompromised
43
Because Polio is a non-enveloped virus, it is very...
Hardy
44
T/F
| Poliomyelitis causes permanent damage.
True
*destroys motor neurons in the spinal cord
45
How big is the iceberg effect in Polio?
| How many infected are paralyzed?
95% asymptomatic
| 0.5%
46
Where is the reservoir for Polio?
Humans
*only infects humans
47
How long is the Polio virus present in stool?
3-6 weeks
*long infective period
48
When was the "last case" of Polio in US?
1981
*Global eradication goal of year 2000 not met
49
What type of virus is Influenza?
family?
enveloped/naked?
+/- RNA/DNA?
Orthomyxovirus
Enveloped
(-)ssRNA
50
What must Influenza bring with it into the cell?
Functional RNA polymerase
*-ssRNA virus
51
What allows the Influenza virus to so effectively mutate?
It is a segmented virus
*allows for genome mixing
52
What are the 2 important spike proteins of influenza?
| Why are they important?
N - neuraminidase
H - hemagglutinin
complete segments are exchanged with other viruses in the cell.
53
What is the mixing of different expressions of the N and H protein called?
Antigenic shift
*can cause Pandemics
54
What is a viral point mutation causing new epitope expression called?
Antigenic drift
55
H and N of the following:
2009 swine flue
avian influenza
H1N1
| H5N1
56
Why are RNA viruses more mutagenic than DNA?
lacks "spell check" mechanism
57
When influenza infects a cell
__ gets in
__ gets out
H
N
*these are both Spike proteins
58
Where does influenza replicate in the cell?
Nucleus
59
T/F
Hemagglutin facilitates viral attachment
Nuraminidase helps viral release
True
60
What is a fast way to determine if someone is carrying antibodies to a specific influenza strain?
Hemagluttination Inhibition Assay
61
What causes many deaths from Influenza?
Lung becomes "denuded" and susceptible to secondary opportunists (staph and strep)
62
What identifies the 3 Influenza types?
What are they?
Which cause human disease?
Capsid antigens
A,B,C
A and B
63
What does it mean that flu vaccines are usually "trivalent?"
They have 2 A and 1 B component
64
What do the following Antiviral Drugs do?
Amantadine and Rimantadine
Oseltamivir (Tamiflu) and Zanamivir (Relenza)
Blocks viral uncoating
| Inhibits neuramidase viral release from cell
65
Influenza Pandemics most often come from _____ and epidemics most often come from _____.
Type A
| A and B
66
What determines the subtypes of the A influenza virus?
Hemagglutinin
| Neuraminidase
67
How many types of Hemagglutinin are there?
| Neuraminidase?
16
| 9
68
What is the reservoir for Type A influenza?
Animals
*we can't vaccinate ourselves out of the disease
69
What does Type A influenza cause?
Epidemics and Pandemics
70
What is the reservoir for Type B influenza?
Humans only
| milder, mostly young and old are infected
71
With influenza, what type of mutation is major?
Shift mutation
*this causes new subtypes of H and N
72
What causes minor mutations in influenza?
Drift mutaions
*point mutations
73
How is the inactivated flu vaccine administered?
| Activated/attenuated?
shots
| mist
74
How does the Quadravalent flu vaccine differ from the Trivalent?
Quad - 2 most probable A and B types
75
What is the average efficacy of the influenza vaccine?
60%
*depends on age, works poorly with elderly
76
What are the normal animal vector pathways used by the Influenza virus?
Fowl to Pig to Human
| or vice versa
77
What does Hepatitis mean?
Inflammation of the Liver
78
There is no cross immunity of the Hepatitis viruses with what exception?
HBV and HDV
79
What is the viral load in the blood with both HBV and HCV?
Huge.
80
With so many viruses that damage the liver, how do we determine a Hep virus?
If it lives in and damages hepatocytes
81
What blood factor is increased by Hep virus liver damage?
Transaminase
82
Which Hepatitis viruses are non-enveloped?
| How are they transmitted?
HAV and HEV
| oro-fecally
83
Which Hep viruses are enveloped?
| How are they transmitted?
HBV, HCV, HDV
| vertical, sex, droplets
84
Which Hep viruses have no chronic condition?
Hep A and Hep E
*either live or die, Acute Only
85
What 2 ways can we prevent Hep A infection?
HAIG (immune globulin) - can be used pre or post infection
Vaccine
86
T/F
| Hep B has immunoglobulin therapy and available vaccine.
True
HBIG and vaccine
87
T/F
| There are no products that prevent HepC
True
*although there is now an expensive $84k cure
88
What does HBV prevention also affect?
HDV
89
T/F
| There are no prevention measures for HEV other than sanitation measures
True
90
What demographic is susceptible to HEV?
Women 3rd Trimester
20% Die
*Developing countries
91
What Hep causes most deaths/yr in the US?
HCV
| 20k chronic
92
T/F
| Fulminant (acute) Hep death is rare.
True
93
HAV virus:
type?
enveloped/naked?
Picornavirus (+ssRNA)
Naked
*sturdy and acute
94
T/F
| HAV has a single serotype worldwide
True
95
T/F
| HAV can be asymptomatic
True
96
T/F
| HAV vaccine has been available since the 1960's
False
| 1996
97
Does HAV have carriers?
| Why?
No
Acute (or asymptomatic) infection only
*after which immune
98
HBV:
type?
enveloped/naked?
dsDNA Hepadnaviridae
| Enveloped
99
T/F
| There is single worldwide serotype for HBV
True
100
T/F
| There can be an acute, asymptomatic, or chronic infection with HBV.
True
101
If exposed to HBV, what is the rate of developing a chronic infection for an adult?
For a baby?
10% (90% resolution)
90% (25% go on to major consequences)
102
T/F
| HBV vaccine has been available since 1981
True
*inactivated
103
What is the primary component of the Hepatitis B vaccine?
HBsAg
(surface antigen)
*this is a Spike Protein
104
Why are health care personnel so at risk for HBV?
very big viral loads among chronically infected
105
What are the 2 major consequences of chronic HBV?
Liver tumors
| Cirrhosis
106
What is responsible for the pathology surrounding HBV?
Cell-mediated immunity and inflammation
*this also eliminated HBV infection
107
T/F
| HBV is double-stranded DNS virus
True
108
What 3 immune components eliminate HBV in 90% of adult cases?
B, Th, and Tc
109
dsDNA virus in HBV goes DNA RNA RNA DNA
True
110
T/F
| There is no treatment for Chronic HBV
True
*unlike HCV (new)
111
How do retroviruses reverse the process of the host cell?
Enter as (+)ssRNA
(mRNA equivalent)
converted to dsDNA
112
T/F
| HIV is a diploid virus.
True
113
T/F
| HIV frequently changes host range and causes tumors inhumans
True
114
What is the enzyme in retroviruses that transcribes RNA to DNA?
Reverse Transcriptase
115
Exogenous viruses are transferred...
| Endogenous viruses are transferred...
```
Horizontally
Vertically (these are integrated into germ line)
```
116
What is a sexually transmitted human leukemia?
| Where is it endemic?
HTLV-1
| Japan, SE asia
117
HIV-1 and HIV-2 are what type of Retrovirus?
Lentivirus
118
What percentage of the human genome is made of past retrovirus?
8%
(almost all turned off)
*endogenous
119
What are the 3 Exogenous retrovirus families?
Oncovirus
Lentivirus
Spumavirus
*spuma has to overt pathology
120
Why are STI's a major risk factor in contracting HIV?
Some cause ulcers, and any breach in mucosa greatly increases risk
*Chlamydia type in Africa causes ulcers
121
T/F
| Babies born to mothers with HIV generally carry the disease
False
If Mother is on anti-retrovirals good chance child HIV free
122
How many people have HIV worldwide?
| New infections/yr?
35 million
| 2 million
123
How many deaths are there from HIV worldwide per year?
1.6 million
124
What type of HIV causes the preponderance of infection?
HIV-1
125
Why do Anti-HIV drugs eventually stop working?
| What is generally the 1st symptom of crisis phase?
High mutation
| Thrush
126
What makes up the ends of HIV?
| What makes up the spike complex?
LTR - long terminal repeat
| GP120 and GP41
127
What protein in HIV is targeted by a number of protease drugs?
Reverse transcriptase
128
Describe how HIV enters a cell.
GP120 binds first to CD4
| GP41 binds and activates Chemokines
129
What is the receptor for GP120?
| What is the receptor for GP41?
CD4
| CCR5
130
What cells have CD4 and CCR5 receptors?
Th (mostly)
| macrophage (some)
131
What are the 6 steps of HIV replication?
```
Attachment
Entry
Reverse Transcription
Integration
Transcription/Translation
Assembly of new HIV
```
132
What base deletion is responsible for HIV resistance?
| What percentage has this in both alleles?
CCR5
1% northern europeans
*CCR5 removal VERY promising HIV therapy
133
What is the current treatment for HIV?
HAART - Highly active anti retroviral therapy
| 5 drugs
134
Why is a dentist often the first to notice AIDS?
Oral diseases appear first as Th cells fall below 200.
135
What is the most communicable disease?
Measles
aka Rubeola
*300k keeps infection going
136
T/F
| There is no iceberg effect with measles
True
*because of its communicability
137
What class of virus causes Measles?
Enveloped/nake?
RNA/DNA?
Paramyxovirus
Enveloped
-ssRNA
138
How is measles transmitted?
Respiratory droplets
139
What causes the characteristic Measles rash?
Tc cells targeting infected capillary endothelium
140
T/F
| Cytotoxic T-cells (Tc) and Immunoglobulins usually completely eliminate measles.
True
141
What feature in Measles infection synergizes with poverty and malnourishment?
Immune Amnesia
*Measles targets memory cells causing window of immunosuppression
142
What 2 diseases are caused by (-)ssRNA Paramyxovirus?
Measles and Mumps
143
What is the main difference between Measles and Mumps?
Mumps has an iceberg effect
*Measles has no asymptomatic carriers
144
What is the characteristic symptom of Mumps?
Parotitis
(painful swelling of salivary glands)
*can also infect testicular ducts
145
What is German Measles?
Rubella
146
T/F
| Rubella is comparatively benign
True
147
When would a fetus be at risk for Rubella?
1st Trimester
*leads to birth defects
148
Rubella:
type?
Enveloped/naked?
Transmission?
Togavirus (+ssRNA)
Enveloped
Respiratory droplets
149
When is the Measles Mumps Rubella vaccine generally given?
12-14 months
booster before school
150
What is the reservoir for the MMR viruses?
Humans Only
151
What is by far the most important of the MMR diseases?
Measles
*because drop in vaccinations/loss of Herd Immunity
152
T/F
| MMR are all ssRNA and enveloped
True
153
What white spots associated with Measles used to be diagnostic?
Koplik spots
154
What can Mumps viremia cause in the 1st trimester?
Spontaneous abortion
155
Why are ssRNA, enveloped, zoonotic infections on the rise?
Encroachment into reservoirs
| Rapid transmission
156
Novel, vector borne viruses can either be _____ or _____.
Accidental
Dead End
*often very virulent
157
Why is zoonotic infection more common outside Hunter/Gatherer societies?
Diseases tend to Burn Out in Hunter/Gatherer
Large population/interaction
158
What is a novel virus from an insect?
| From rodent?
Arbovirus
| Robovirus
159
Arbovirus and Robovirus often cause what 2 conditions in humans?
Encephalitis
| Hemorrhagic fevers
160
T/F
| All vector borne viruses are enveloped and ssRNA
True
161
What type of pathology is induced by the Togaviruses (Rubella) and Flaviviruses (West Nile, Dengue)?
these are Arboviruses
Encephalatic: Rubella, West Nile
Hemmorhagic: Dengue
*Rubella exception, was once vector born Arbovirus but now its ours and is spread via respiratory aerosols
162
What is the reservoir for Hanta?
| What kind of virus is it?
Desert Mous rat
Robovirus
*causes hemorrhagic fever (capillaries collapse)
163
How are roboviruses transmitted?
Fecally by rodents
| including bats, etc
164
Why do vector-borne zoonotics often jump species?
ssRNA enveloped viruses have very high mutation rate
165
What do Prions cause?
Transmissible Spongiform Encephalopathies
166
Name 5 Prion diseases.
```
Kuru
Creutzfeldt-Jacob
Scrapie
BSE
Chronic wasting
```
167
T/F
| Prions are larger than bacteria
False
168
Do Prions elicit an immune response?
No
169
Describe a PrP
Protease resistant
Hydrophobic glycoprotein
(aggregate)
170
What is an accumulation of PrP's in the CNS called?
Ameloid
171
Prions were once called...
Slow viruses
172
How are new Prions formed?
| What is the disease progression?
Contact existing Prion causes folding
| Prions > Ameloid > disease
173
If infected with smallpox, what were the chances of dying?
| Terrible scarring?
1/3
| 1/3
174
What is the 1st and only infectious disease eliminated worldwide?
Smallpox
175
Smallpox:
nucleic acid type?
enveloped/naked?
transmission?
dsDNA
Complex (both enveloped and naked)
Respiratory droplets
176
The Middle Age technique of harvesting scabs at the end of a smallpox outbreak and applying it to cuts on the forehead after a time is called?
Variolation
177
What were the probable vectors for SARS and MERS?
Bats
