Exam2Lec8RNAviruses Flashcards

1
Q

What is the genome and sense of picornavirus

A

RNA genomes and positive sense, ss

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2
Q

What is the capsid symmetry of picornavirus

A

Iscoahedral capsid symmetry

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3
Q

Where is the replication of picornavirus

A

Cytoplasmic

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4
Q

T/F picornavirus has variable host range

A

True

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5
Q

What is the illness of picornavirus

A

Respiratory, GI, cardiac, hepatic illness
“common cold” (rhino, entero)

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6
Q

What are the exact examples we do for class?

A

Rhinovirus (HRV14)
EV-D68
Poliovirus

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7
Q

What is the tropism of entero-

A

GI tract (includes coxsackie A,B and echo)

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8
Q

What is the tropism for coxsackie

A

A: skin, mucous membranes
B: heart, lungs, liver

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9
Q

What is the tropism for Rhino-

A

URT

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10
Q

What is the tropism for Hep A

A

Liver

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11
Q

What does the picornavirus family cause?

A

Respiratory, GI, cardiac, hepatic illness

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12
Q

Positive stranded viral genomic RNA is what?

A

mRNA and considered infectious

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13
Q

What allows the facilitates interaction with ribosomes

A

Viral RNA has a 5’ internal ribosome entry site (IRES) sequence that facilitates interaction with ribosomes.

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14
Q

What is the problem and resolution of single segment?

A

Problem: single gene

Resolution: viral protease
- Clips polyprotein into smaller functional subunits

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15
Q

What is an example of viral protease?

A

Poliovirus

3c=protease

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16
Q

What is not capped in genomic RNA , and has what instead?

A

5’ end of genomic RNA is not capped, instead has viral VPg protein bound

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17
Q

What is the structure of Rhinovirus

A

ss(+) RNA, icosahedral
Serotypes:>200

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18
Q

What is the transmission of Rhinovirus

A

Fomite
Respiratory (surgical / N95)
Sensitive to low pH
Cannot grow above 33oC ⭐️

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19
Q

What is the seasonality of Rhinovirus

A

Peaks in Fall (predominant), Spring
More severe infection in Winter

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20
Q

When you see rhinovirus, what should you think?

A

Common colds

Makes up 1/3 to 1/2 of all acute respiratory infection in humans

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21
Q

What is the common cold symptoms

A

Coryza/rhinitis: congestion, runny nose
Pharyngitis: sore throat
Cough
Low-grade fever, if any

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22
Q

Causes of common cold

A

Rhinoviruses
Coronaviruses
Parainfluenza viruses

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23
Q

What should be used for large droplets

A

surgical mask

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24
Q

what should be used for small droplets

A

N95

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25
Q

Common cold is what type of illness

A

Common cold is a self-limited illness.

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26
Q

Common colds account for how many respiratory infections in humans

A

one-third to one-half

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27
Q

What is the virus that is similar to rhinoviruses

A

Enterovirus D68

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28
Q

What is the structure of Enterovirus D68

A

Structure: ss (+) RNA, icosahedral

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29
Q

What does Enterovirus can cause

A

EV-D68 can cause mild to severe respiratory illness.

Mild symptoms may include fever, runny nose, sneezing, cough, and body and muscle aches.

Severe symptoms may include wheezing and difficulty breathing.

Linked to acute flaccid myelitis (AFM) ⭐️

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30
Q

What is unique to EV-D68 disease

A

Linked to acute flaccid myelitis (AFM) ⭐️

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31
Q

What is seasonality in Enterovirus D68

A

Peaks In summer.fall
- earlier than rhinovirus

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32
Q

Where has the EV D68 have been recently

A

US Europe and Asia

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33
Q

What does poliovirus infect

A

Infects cells in the gut/intestinal lining, specifically the associated lymphoid tissue (GALT)

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34
Q

What are the symptoms of Poliovirus

A

Typically, asymptomatic infection (~70%)

Mild symptoms: sore throat, fever, malaise (~25%)

Rare CNS involvement: aseptic meningitis
Can progress to poliomyelitis

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35
Q

What is unique about poliovirus

A

Rare CNS involvement: aseptic meningitis
Can progress to poliomyelitis

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36
Q

What is poliomyelitis

A

virus targets CNS= paralysis

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37
Q

What is the poliovirus vaccine in the US

A

4 doses of inactivated polio vaccine (IPV, Salk)

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38
Q

What does the current vaccine (US) prevent?

A

ONLY POLIOMYELITIS, not infection

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39
Q

What is the polio vaccine out if the US

A

Live attenuated vaccine (OPV)

Bivalent (Types 1 and 3): Type 2 eradicated in 1999

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40
Q

What is the problem of the live attenuated vaccine out of US

A

can cause circulating vaccine- derived poliovirus (cVDPV)
- mostly type 2

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41
Q

Where is poliovirus endemic in?

A

Pakistan and Afghanistan

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42
Q

What is the Genomes of caliciviruses family

A

RNA Genomes

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43
Q

what is the sense of caliciviruses family

A

positive sense, ss

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44
Q

What is the capsid symmetry of Caliciviruses Family

A

Icosahedral

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45
Q

What is the replication of caliciveuses family

A

Cytoplasmic

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46
Q

What is host range of Caliciviruses family

A

narrow host range

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47
Q

what illness does Caliciviruses family cause

A

GI illness

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48
Q

What is the most common cause of viral gastroenteritis

A

Noroviruses

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49
Q

what is common in Noroviruses

A

Family and community outbreaks common (cruise ship outbreaks)

Especially in closed communities, e.g. day care

50
Q

T/F Noroviruses is not age limited like rotavirus

A

True

Incidence is highest in children < 5 yo
Severe gastroenteritis in elderly (> 65 yo)

51
Q

What is the transmission of Noroviruses

A

Fecal oral route

52
Q

What is the family of rotavirus

A

Reovirus family

53
Q

What is the genome of rotavirus

A

DsRNA

54
Q

What is the structure of rotavirus?

A

Icosahedra

DOUBLE LAYERED

55
Q

What is special of rotavirus?

A

Ds RNA

DOUBLE LAYER

56
Q

Where does rotavirus replicate?

A

replicates in cytoplasm

57
Q

What is the predominant group of rotavirus

A

group A

58
Q

what time of the year is rotavirus more predominant

A

winter month

59
Q

More SERVE gastroenteritis than other GI pathogens

A

Rotavirus

60
Q

rotavirus causes ___ severe gastroenteritis than other GI pathogens

A

more

61
Q

What group of people are more severe

A

8 – 10% of all diarrhea; 35 – 40% of diarrhea requiring hospitalization

Most severe in children 4 – 23 months

62
Q

How is Rotavirus transmitted

A

Fecal-oral transmission

63
Q

What is the incubation period of rotavirus

A

Incubation period 1-3 days

64
Q

What is the clinical characteristic of rotavirus ?

A

Characteristic clinical triad (vomit, diarrhea and fever)
—-Abrupt onset
vomiting (1-3 d) then diarrhea (5-8 d)
—-low grade fever

65
Q

Where do you see fatal disease of rotavirus

A

Severe fatal disease in malnourished or immune suppressed

Resource poor countries - a leading cause of infant mortality

66
Q

What is the prevention of rotavirus

A

Vaccine live, attenuated recombinant (RotaShield)
—Approved for use in 1999
—-Removed from market in late 1999 due to problems with intussuception

Current vaccines
—RotaTeq® (RV5) 3 doses at 2, 4, and 6 months
—-Rotarix® (RV1) 2 doses at 2 and 4 months

GOOD HYGIENE

67
Q

Details about negative strand viruses

A

genomic RNA is complementary sense of mRNA

Viral genomic RNA cannot direct virus life cycle.
– must be first transcribed into mRNA.

Thus, the genome is not infectious when introduced into cells. (in contrast to positive-sense viruses)

68
Q

What are the primary features of (-) strand viruses

A

Gene expression regulated by internal transcriptional initiation from negative-strand template.

Viruses must package functional polymerases in virions.

Negative-sense viruses can have multiple segments in their genome.

Many “emerging” viruses are negative-strand!!

69
Q

What - sense must have?

A

Viruses must package functional polymerases in virions.

70
Q

What are the nonsegmented negative sense RNA viruses

A

filoviruses: Ebola, Marburg

paramyxoviruses: measles, mumps

71
Q

What are the segmented negative sense RNA viruses

A

orthomyxoviruses: influenza A, B, C

72
Q

For paramyxoviruses what is the genome and sense

A

RNA genome

negative sense, ss (~ 15 kb)

73
Q

What is the caspsid symmetry of paramyxovirus

A

Helical
encapsidated

74
Q

What is the replication of paramyxovirus

A

Cytoplasmic

75
Q

what is the host range of paramyxovirus

A

Narrow host range

76
Q

What is the illness of paramyxovirus

A

respiratory and neurologic illness

77
Q

Paramyxovirus gene expression

A

1.Transcription by viral polymerase (L and P).

  1. Single promoter at 3´ end.
  2. Linear array of genes.
  3. Each gene bounded by transcription initiation and transcription termination signals. ⭐️
  4. Sequential transcription of genes.
  5. Transcriptional attenuation due to polymerase dissociation at gene junctions (gradient of expression). ⭐️
78
Q

How does disease state of measles vary among areas

A

Temperate areas : Mild disease
Tropical areas: Severe disease

79
Q

what is the incubation period of measles and the symptoms

A

Incubation up to 2 weeks

Prodromal stage to rash 2-3 days with running eyes and nose
—Koplik spots (enanthem): rash in mouth
—Rash starts in face and migrates to trunk: Maculopapular eruption
—Temperature rises to ~40⁰C
—Bronchitis and pneumonitis (rales)

80
Q

What is the transmission of measles

A

Droplets enter respiratory tract or eye

81
Q

What is the prodromal stage of measles

A

Primary replication on respiratory epithelial cells
- bronchitis and pneumonities (rales)
-running eyes and nose
-high fever

82
Q

Where does measles replicated in the body (primary and secondary)

A

Primary replication on respiratory epithelial cells

Secondary replication in mononuclear cells (lymph nodes)

83
Q

Measles is shed in what ?

A

Shed in body fluids

84
Q

What can measles secondary replication in mononuclear cells cause

A

Causes leukopenia

85
Q

What is responsible for pathogenesis of rash in measles

A

Cytotoxic T cells

86
Q

What plays a role in pathogenesis and severity of measles

A

Giant cell formation

87
Q

What is major reason for killing children with measles? how does this happen

A

secondary infection

measles kills are memory cells so susceptible for second infection

88
Q

The virus travels to body surfaces and causes what?

A

kopek spots (enanthem)

Maculopapular rash (face to trunk)

89
Q

What is unique about the rash of measles

A

face to trunk

90
Q

What is the lung infection of measles

A

temporary respiratory illness

91
Q

What is the oral mucosa infection of measles

A

Koplik’s spots

92
Q

What is the skin infection of measles

A

maculopapular rash

93
Q

What is the overall impact of measles

A

Transient generalized immunosuppression

2 infections

94
Q

For Filoviruses what is the genomes and sense

A

RNA genomes

single strand, negative sense (~19kb)

95
Q

For Filoviruse family what is the genomes and sense

A

RNA genomes

single strand, negative sense (~19kb)

Longest genome of any negative sense virus

96
Q

What is the caspid symmetry for filoviruse family

A

encapsulated, helical capsid symmetry

filamentous

97
Q

What is the replication of filoviruse family

A

cytoplasmic

98
Q

What does filoviruses family cause

A

acute infection

99
Q

extra details of filoviruses

A

Tropism for monocytes, hepatocytes, endothelial cells

Receptor (EBOV): Niemann-Pick C1

100
Q

When does ebola symptoms appear?

A

Symptoms may appear anywhere from 2 to 21 days after exposure to Ebola virus, although 8-10 days is most common.

101
Q

How does ebloa spread?

A

one person to another through direct contact with blood, urine, saliva, feces, vomit, semen and needles

102
Q

who has the highest risk of Ebola

A

Healthcare works, family, friends and others who come into close contact with ebola infected patients

103
Q

What does elbow primarily infects ?

A

Endothelia cells, dendiritic cells and macrophages

104
Q

What happens with endothelial cell infection

A

hemorrhage and organ failure

105
Q

What happens with dendritic cells infection

A

decrease immune system

106
Q

What happens with macrophages infection

A

Induces release of excess cytokines (cytokine storm) which causes systemic inflammation

107
Q

What is the genome of Orthomyxozovirus family

A

RNA genome
neg sense
ss
encapsulated
8 SEGMENTS

108
Q

What is the capsid symmetry of orthomyxovirus family

A

Helical

109
Q

What are the two types of particles that orthomyxovirus family can cause

A

spherical and filamentous

110
Q

what is the replication of orthomyxovirus family

A

nuclear replication ⭐️

111
Q

what does the orthomyxovirus family cause

A

respiratory illness

112
Q

What is in the orthomyxovirus family

A

Influenza

113
Q

How many types of Influenza is there

A

3 human types
-immunize : A and B
-C is not problematic

114
Q

When does synpotims begin for Influenza

A

1-4 days after infection

115
Q

when is the infectious phase of Influenza

A

1 day before 3-4 days after symptoms begin

116
Q

What are the symptoms of Influenza

A

sudden onset of chills and fever
sore throat, dry cough
fatigue and malaise
myalgia headaches dizziness
diarrea
bronchitis pneumonia

117
Q

How long is recovery of Influenza and due to what

A

recovery takes 1-3 weeks after viral clearance due Tod damage left behind

118
Q

What is the vital attachment of Influenza

A

HA (hemagglutinin)

119
Q

What is the enzyme that cleaves the hemagglutin

A

NA (neuraminidase)

120
Q

What is antigenic drift and shift

A

drift: accumulation of point mutations (small changes ) to Influenza surface antigens (HA and NA)

shift:reassortment of genomic segment (big change) leading to entirely different surface antigen (HA and NA)

121
Q

what is responsible of influenza epidemics?

A

antigenic drift