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Flashcards in Microbiology III Deck (177)
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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
Q

What receptor is integral in moving new IgA from B-emmigrant cells onto mucosal surface?

A

poly-lg Fc receptors

takes off B cells

26
Q

What protects sIgA dimers from proteases on the mucosal surface?
Where does this come from?

A

secretory component

protease that cleaved sIgA from poly-lg Fc receptor

27
Q

How does sIgA protect neonates?

A

Through mother’s milk

Stays in intestinal lumen

28
Q

What 2 places does a baby’s passive immunity come from?

A

sIgA in gut through milk

IgG through placental transfer

29
Q

IgA found outside the body is _____, while IgA found inside the body is typically ______.

A

Dimeric

Monomeric

30
Q

T/F

sIgA is a poor activator of Complement and an inconsistent opsonizer.

A

True

31
Q

What does anergy refer to in oral tolerance?

What is the main inhibitory cytokine involved?

A

High Ag feeding induces tolerance

TGF-beta

32
Q

What is the immunoglobulin complex that sticks to mucins?
What is this resistant to?
What does it block?

A

sIgA2
Proteases
Colonization

33
Q

What are the specialized APC’s found in the mucosa?

A

M-cells

34
Q

What does sIgA stick to on mucosal surfaces?

A

mucins

35
Q

What type of virus is Polio?

A

Picornavirus

36
Q

Polio is enveloped/naked
is a (what stranded) RNA
usually found what part of body

A

Naked
(+)RNA
enterovirus

37
Q

Where does Polio bind in the body and replicate?

A

Oropharynx/GI tract

38
Q

How is Polio transmitted?

What are its viremic effects?

A

Oro-fecally

Neurotropic

39
Q

What prevents initial colonization of the Polio virus?

What prevents viremia?

A

sIgA

IgG

40
Q

What Polio vaccine is killed and induces IgG?

Which one is attenuated-live and induces sIgA and IgG?

A

Salk

Sabin

41
Q

What are the Oro-Fecal considerations of the Polio vaccines?

A

Salk - 2 month window of continued fecal Polio excretion

Sabin - Fecal sIgA will confer bystander immunity

42
Q

Even though it confers IgG, sIgA, and bystander immunity, what is a downside to the Sabin vaccine?

A

Can infect immunocompromised

43
Q

Because Polio is a non-enveloped virus, it is very…

A

Hardy

44
Q

T/F

Poliomyelitis causes permanent damage.

A

True

*destroys motor neurons in the spinal cord

45
Q

How big is the iceberg effect in Polio?

How many infected are paralyzed?

A

95% asymptomatic

0.5%

46
Q

Where is the reservoir for Polio?

A

Humans

*only infects humans

47
Q

How long is the Polio virus present in stool?

A

3-6 weeks

*long infective period

48
Q

When was the “last case” of Polio in US?

A

1981

*Global eradication goal of year 2000 not met

49
Q

What type of virus is Influenza?
family?
enveloped/naked?
+/- RNA/DNA?

A

Orthomyxovirus
Enveloped
(-)ssRNA

50
Q

What must Influenza bring with it into the cell?

A

Functional RNA polymerase

*-ssRNA virus

51
Q

What allows the Influenza virus to so effectively mutate?

A

It is a segmented virus

*allows for genome mixing

52
Q

What are the 2 important spike proteins of influenza?

Why are they important?

A

N - neuraminidase
H - hemagglutinin

complete segments are exchanged with other viruses in the cell.

53
Q

What is the mixing of different expressions of the N and H protein called?

A

Antigenic shift

*can cause Pandemics

54
Q

What is a viral point mutation causing new epitope expression called?

A

Antigenic drift

55
Q

H and N of the following:
2009 swine flue
avian influenza

A

H1N1

H5N1

56
Q

Why are RNA viruses more mutagenic than DNA?

A

lacks “spell check” mechanism

57
Q

When influenza infects a cell
__ gets in
__ gets out

A

H
N

*these are both Spike proteins

58
Q

Where does influenza replicate in the cell?

A

Nucleus

59
Q

T/F
Hemagglutin facilitates viral attachment
Nuraminidase helps viral release

A

True

60
Q

What is a fast way to determine if someone is carrying antibodies to a specific influenza strain?

A

Hemagluttination Inhibition Assay

61
Q

What causes many deaths from Influenza?

A

Lung becomes “denuded” and susceptible to secondary opportunists (staph and strep)

62
Q

What identifies the 3 Influenza types?
What are they?
Which cause human disease?

A

Capsid antigens
A,B,C
A and B

63
Q

What does it mean that flu vaccines are usually “trivalent?”

A

They have 2 A and 1 B component

64
Q

What do the following Antiviral Drugs do?
Amantadine and Rimantadine
Oseltamivir (Tamiflu) and Zanamivir (Relenza)

A

Blocks viral uncoating

Inhibits neuramidase viral release from cell

65
Q

Influenza Pandemics most often come from _____ and epidemics most often come from _____.

A

Type A

A and B

66
Q

What determines the subtypes of the A influenza virus?

A

Hemagglutinin

Neuraminidase

67
Q

How many types of Hemagglutinin are there?

Neuraminidase?

A

16

9

68
Q

What is the reservoir for Type A influenza?

A

Animals

*we can’t vaccinate ourselves out of the disease

69
Q

What does Type A influenza cause?

A

Epidemics and Pandemics

70
Q

What is the reservoir for Type B influenza?

A

Humans only

milder, mostly young and old are infected

71
Q

With influenza, what type of mutation is major?

A

Shift mutation

*this causes new subtypes of H and N

72
Q

What causes minor mutations in influenza?

A

Drift mutaions

*point mutations

73
Q

How is the inactivated flu vaccine administered?

Activated/attenuated?

A

shots

mist

74
Q

How does the Quadravalent flu vaccine differ from the Trivalent?

A

Quad - 2 most probable A and B types

75
Q

What is the average efficacy of the influenza vaccine?

A

60%

*depends on age, works poorly with elderly

76
Q

What are the normal animal vector pathways used by the Influenza virus?

A

Fowl to Pig to Human

or vice versa

77
Q

What does Hepatitis mean?

A

Inflammation of the Liver

78
Q

There is no cross immunity of the Hepatitis viruses with what exception?

A

HBV and HDV

79
Q

What is the viral load in the blood with both HBV and HCV?

A

Huge.

80
Q

With so many viruses that damage the liver, how do we determine a Hep virus?

A

If it lives in and damages hepatocytes

81
Q

What blood factor is increased by Hep virus liver damage?

A

Transaminase

82
Q

Which Hepatitis viruses are non-enveloped?

How are they transmitted?

A

HAV and HEV

oro-fecally

83
Q

Which Hep viruses are enveloped?

How are they transmitted?

A

HBV, HCV, HDV

vertical, sex, droplets

84
Q

Which Hep viruses have no chronic condition?

A

Hep A and Hep E

*either live or die, Acute Only

85
Q

What 2 ways can we prevent Hep A infection?

A

HAIG (immune globulin) - can be used pre or post infection

Vaccine

86
Q

T/F

Hep B has immunoglobulin therapy and available vaccine.

A

True

HBIG and vaccine

87
Q

T/F

There are no products that prevent HepC

A

True

*although there is now an expensive $84k cure

88
Q

What does HBV prevention also affect?

A

HDV

89
Q

T/F

There are no prevention measures for HEV other than sanitation measures

A

True

90
Q

What demographic is susceptible to HEV?

A

Women 3rd Trimester
20% Die

*Developing countries

91
Q

What Hep causes most deaths/yr in the US?

A

HCV

20k chronic

92
Q

T/F

Fulminant (acute) Hep death is rare.

A

True

93
Q

HAV virus:
type?
enveloped/naked?

A

Picornavirus (+ssRNA)
Naked

*sturdy and acute

94
Q

T/F

HAV has a single serotype worldwide

A

True

95
Q

T/F

HAV can be asymptomatic

A

True

96
Q

T/F

HAV vaccine has been available since the 1960’s

A

False

1996

97
Q

Does HAV have carriers?

Why?

A

No
Acute (or asymptomatic) infection only

*after which immune

98
Q

HBV:
type?
enveloped/naked?

A

dsDNA Hepadnaviridae

Enveloped

99
Q

T/F

There is single worldwide serotype for HBV

A

True

100
Q

T/F

There can be an acute, asymptomatic, or chronic infection with HBV.

A

True

101
Q

If exposed to HBV, what is the rate of developing a chronic infection for an adult?
For a baby?

A

10% (90% resolution)

90% (25% go on to major consequences)

102
Q

T/F

HBV vaccine has been available since 1981

A

True

*inactivated

103
Q

What is the primary component of the Hepatitis B vaccine?

A

HBsAg
(surface antigen)

*this is a Spike Protein

104
Q

Why are health care personnel so at risk for HBV?

A

very big viral loads among chronically infected

105
Q

What are the 2 major consequences of chronic HBV?

A

Liver tumors

Cirrhosis

106
Q

What is responsible for the pathology surrounding HBV?

A

Cell-mediated immunity and inflammation

*this also eliminated HBV infection

107
Q

T/F

HBV is double-stranded DNS virus

A

True

108
Q

What 3 immune components eliminate HBV in 90% of adult cases?

A

B, Th, and Tc

109
Q

dsDNA virus in HBV goes DNA RNA RNA DNA

A

True

110
Q

T/F

There is no treatment for Chronic HBV

A

True

*unlike HCV (new)

111
Q

How do retroviruses reverse the process of the host cell?

A

Enter as (+)ssRNA
(mRNA equivalent)
converted to dsDNA

112
Q

T/F

HIV is a diploid virus.

A

True

113
Q

T/F

HIV frequently changes host range and causes tumors inhumans

A

True

114
Q

What is the enzyme in retroviruses that transcribes RNA to DNA?

A

Reverse Transcriptase

115
Q

Exogenous viruses are transferred…

Endogenous viruses are transferred…

A
Horizontally
Vertically (these are integrated into germ line)
116
Q

What is a sexually transmitted human leukemia?

Where is it endemic?

A

HTLV-1

Japan, SE asia

117
Q

HIV-1 and HIV-2 are what type of Retrovirus?

A

Lentivirus

118
Q

What percentage of the human genome is made of past retrovirus?

A

8%
(almost all turned off)

*endogenous

119
Q

What are the 3 Exogenous retrovirus families?

A

Oncovirus
Lentivirus
Spumavirus

*spuma has to overt pathology

120
Q

Why are STI’s a major risk factor in contracting HIV?

A

Some cause ulcers, and any breach in mucosa greatly increases risk

*Chlamydia type in Africa causes ulcers

121
Q

T/F

Babies born to mothers with HIV generally carry the disease

A

False

If Mother is on anti-retrovirals good chance child HIV free

122
Q

How many people have HIV worldwide?

New infections/yr?

A

35 million

2 million

123
Q

How many deaths are there from HIV worldwide per year?

A

1.6 million

124
Q

What type of HIV causes the preponderance of infection?

A

HIV-1

125
Q

Why do Anti-HIV drugs eventually stop working?

What is generally the 1st symptom of crisis phase?

A

High mutation

Thrush

126
Q

What makes up the ends of HIV?

What makes up the spike complex?

A

LTR - long terminal repeat

GP120 and GP41

127
Q

What protein in HIV is targeted by a number of protease drugs?

A

Reverse transcriptase

128
Q

Describe how HIV enters a cell.

A

GP120 binds first to CD4

GP41 binds and activates Chemokines

129
Q

What is the receptor for GP120?

What is the receptor for GP41?

A

CD4

CCR5

130
Q

What cells have CD4 and CCR5 receptors?

A

Th (mostly)

macrophage (some)

131
Q

What are the 6 steps of HIV replication?

A
Attachment
Entry
Reverse Transcription
Integration
Transcription/Translation
Assembly of new HIV
132
Q

What base deletion is responsible for HIV resistance?

What percentage has this in both alleles?

A

CCR5
1% northern europeans

*CCR5 removal VERY promising HIV therapy

133
Q

What is the current treatment for HIV?

A

HAART - Highly active anti retroviral therapy

5 drugs

134
Q

Why is a dentist often the first to notice AIDS?

A

Oral diseases appear first as Th cells fall below 200.

135
Q

What is the most communicable disease?

A

Measles

aka Rubeola

*300k keeps infection going

136
Q

T/F

There is no iceberg effect with measles

A

True

*because of its communicability

137
Q

What class of virus causes Measles?
Enveloped/nake?
RNA/DNA?

A

Paramyxovirus
Enveloped
-ssRNA

138
Q

How is measles transmitted?

A

Respiratory droplets

139
Q

What causes the characteristic Measles rash?

A

Tc cells targeting infected capillary endothelium

140
Q

T/F

Cytotoxic T-cells (Tc) and Immunoglobulins usually completely eliminate measles.

A

True

141
Q

What feature in Measles infection synergizes with poverty and malnourishment?

A

Immune Amnesia

*Measles targets memory cells causing window of immunosuppression

142
Q

What 2 diseases are caused by (-)ssRNA Paramyxovirus?

A

Measles and Mumps

143
Q

What is the main difference between Measles and Mumps?

A

Mumps has an iceberg effect

*Measles has no asymptomatic carriers

144
Q

What is the characteristic symptom of Mumps?

A

Parotitis

(painful swelling of salivary glands)

*can also infect testicular ducts

145
Q

What is German Measles?

A

Rubella

146
Q

T/F

Rubella is comparatively benign

A

True

147
Q

When would a fetus be at risk for Rubella?

A

1st Trimester

*leads to birth defects

148
Q

Rubella:
type?
Enveloped/naked?
Transmission?

A

Togavirus (+ssRNA)
Enveloped
Respiratory droplets

149
Q

When is the Measles Mumps Rubella vaccine generally given?

A

12-14 months

booster before school

150
Q

What is the reservoir for the MMR viruses?

A

Humans Only

151
Q

What is by far the most important of the MMR diseases?

A

Measles

*because drop in vaccinations/loss of Herd Immunity

152
Q

T/F

MMR are all ssRNA and enveloped

A

True

153
Q

What white spots associated with Measles used to be diagnostic?

A

Koplik spots

154
Q

What can Mumps viremia cause in the 1st trimester?

A

Spontaneous abortion

155
Q

Why are ssRNA, enveloped, zoonotic infections on the rise?

A

Encroachment into reservoirs

Rapid transmission

156
Q

Novel, vector borne viruses can either be _____ or _____.

A

Accidental
Dead End

*often very virulent

157
Q

Why is zoonotic infection more common outside Hunter/Gatherer societies?

A

Diseases tend to Burn Out in Hunter/Gatherer

Large population/interaction

158
Q

What is a novel virus from an insect?

From rodent?

A

Arbovirus

Robovirus

159
Q

Arbovirus and Robovirus often cause what 2 conditions in humans?

A

Encephalitis

Hemorrhagic fevers

160
Q

T/F

All vector borne viruses are enveloped and ssRNA

A

True

161
Q

What type of pathology is induced by the Togaviruses (Rubella) and Flaviviruses (West Nile, Dengue)?

these are Arboviruses

A

Encephalatic: Rubella, West Nile

Hemmorhagic: Dengue

*Rubella exception, was once vector born Arbovirus but now its ours and is spread via respiratory aerosols

162
Q

What is the reservoir for Hanta?

What kind of virus is it?

A

Desert Mous rat
Robovirus

*causes hemorrhagic fever (capillaries collapse)

163
Q

How are roboviruses transmitted?

A

Fecally by rodents

including bats, etc

164
Q

Why do vector-borne zoonotics often jump species?

A

ssRNA enveloped viruses have very high mutation rate

165
Q

What do Prions cause?

A

Transmissible Spongiform Encephalopathies

166
Q

Name 5 Prion diseases.

A
Kuru
Creutzfeldt-Jacob
Scrapie
BSE
Chronic wasting
167
Q

T/F

Prions are larger than bacteria

A

False

168
Q

Do Prions elicit an immune response?

A

No

169
Q

Describe a PrP

A

Protease resistant
Hydrophobic glycoprotein
(aggregate)

170
Q

What is an accumulation of PrP’s in the CNS called?

A

Ameloid

171
Q

Prions were once called…

A

Slow viruses

172
Q

How are new Prions formed?

What is the disease progression?

A

Contact existing Prion causes folding

Prions > Ameloid > disease

173
Q

If infected with smallpox, what were the chances of dying?

Terrible scarring?

A

1/3

1/3

174
Q

What is the 1st and only infectious disease eliminated worldwide?

A

Smallpox

175
Q

Smallpox:
nucleic acid type?
enveloped/naked?
transmission?

A

dsDNA
Complex (both enveloped and naked)
Respiratory droplets

176
Q

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?

A

Variolation

177
Q

What were the probable vectors for SARS and MERS?

A

Bats

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