Major RNA Viruses Flashcards Preview

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Flashcards in Major RNA Viruses Deck (107)
1

What are the 5 general properties that apply to RNA viruses?

-Enveloped/non-enveloped
- capsid symmetry
- nucleic acid (ss or ds)
- +/- sense, ambisense
- replication location (?)

2

What is + sense RNA?

same RNA reading as host

3

What is - sense RNA?

needs RNA polymerase

4

What classification system is used to classify viruses?

Baltimore classification based on mRNA synthesis

5

Which RNA virus is double stranded?

Reoviridae

6

Which RNA viruses are nonenveloped?

Picornaviridae, Caliciviridaem Reoviridae

7

Where do most RNA viruses replicate? exception?

cytoplasm

Othomyxoviridae, Retroviridae

8

What class is a dsRNA?

Class III

9

What class is a (+)ssRNA?

Class IV

10

What class is a (-)ssRNA?

Class V

11

What class is ssRNA-RT?

Class VI

12

Describe the characteristics of picornaviridae?

+ssRNA
Nonenveloped
Icosahdral
resistant to pH 3-9

13

Where does the picornaviridae replicate?

cytoplasm

14

How is the picornaviridae classified?

Class IV

15

What are 3 genus for picornaviridae?

Enterovirus
Rhinovirus
Hepatovirus

16

What species are included in Enterovirus?

Poliovirus (1-3)
Coxsackie A (1-24)
Coxsackie B (1-6)
Enterovirus (68-71)

17

How are most Enteroviruses transmitted?

fecal oral

18

What cells are infected by the poliovirus?

oropharyngeal
intestinal mucosa

19

What are the clinical manifestations of poliovirus?

90-95% remain subclinical
5-8% flu-like symptoms
1-2% associated with major manifestations: meningitis
encephalitis
paralytic poliomyelitis

20

What are common viruses responsible for meningitis?

enterovirus
coxsackie A&B
echovirus
Arbovirus
HIV
HSV-2

21

What cells are involved in paralytic poliomyelitis?

cells of the anterior horn - results in flaccid paralysis

medulla - paralysis of the diaphragm >>>death

22

What are the 3 types of paralytic polio?

spinal polio (paralytic)
bulbar polio (muscle weakness)
bulbospinal polio

23

How would you diagnose poliovirus?

isolation of virus from stool
CSF (definitive)

24

How would you treat polio?

no specific treatment > supportive
-pain and muscle spasm control
- orthopedic support to prevent contracture, deformities and fracture

25

How do you prevent polio?

Vaccine
OPV (Oral Polio vaccine)
IPV (Inactivated Polio Vaccine)

26

What are the advantages and disadvantages of OPV?

OPV
Good:
-oral, easily administered
-lifelong immunity
- no boosters necessary
Bad:
- risk of vaccine-associated polio
-can't be administered to immunocompromised patients

27

What are the advantages and disadvantages of IPV?

IPV
Good:
- no risk of vaccine associated polio
-safe for immunocompromised patients
-easier to store and transport

Bad:
Booster needed
Injection
Large dose required

28

How is Coxsackievirus transmitted?

fecal-oral

29

How would you treat or prevent Coxsackievirus?

no vaccine or treatment

30

List 5 diseases due to Coxsackievirus A.

A9, A16 - hand, foot and mouth disease
Aseptic meningitis (summer and fall)
Herpangia
A24 - acute hemorrhagic conjunctivitis
A7 - poliomyelitis-like symptoms

31

List 4 diseases due to Coxsackievirus B.

Pleurodynia - "Devil's grip"
*****Myocarditis (leading cause) and pericarditis
B2, B5 - hand, foot and mouth
B4 - juvenile diabetes (IDDM)

32

What are the clinical manifestations of hand, foot and mouth disease?

vesicular rash on hands, feet, mouth and tongue
mild fever

33

What are the clinical manifestations of Herpangina (Coxsackie A)?

fever
sort throat
anorexia
vomiting

vesicular ulcerating lesions on soft palate and uvula

34

What are the clinical manifestations of Conjunctivitis (Coxsackie A)?

eye pain followed by redness
teary painful eyes
swelling
light sensitivity

**highly contagious

35

What are the clinical manifestations of Pleurodynia (Coxsackie B)?

Acute onset of fever
unilateral low thoracic chest pain

"Devil's Grip"

Males may have testicular pain.

36

How is Rhinovirus transmitted?

contact with respiratory secretions

37

What are the symptoms of Rhinovirus?

- runny nose
- common cold

**infections are localized to the nose

38

How is the hepatovirus transmitted?

fecal-oral

39

What is the characteristic of Hepatitis A?

+ssRNA
nonenveloped
icosohedral

40

What are the symptoms of Hepatitis A?

sudden fever
jaundice (self-limiting)

41

How do you prevent Hepatitis A?

Vaccine
-recommended for at-risk groups

42

What system does Hepatitis A infect?

intestinal epithelial cells
-spreads to liver

43

What are the characteristics of Caliciviridae?

+ssRNA
Nonenveloped
icosahedral
resistant to heat and detergents
can be inactivated by acid (pH 3 99% inactivation)

44

How are most Caliciviridae transmitted?

fecal-oral (Norovirus, Sapovirus)

45

How do most Caliciviridae manifest?

gastrointestinal
-diarrhea
-vomiting

46

What is norovirus associated with?

contaminated water supplies and food
- potluck meals
- outbreaks on cruise ships

47

How would you diagnose norovirus?

virus isolated from stool and vomit

48

What are the symptoms of norovirus?

acute gastroenteritis 12-24 hours after ingestion of food

49

How do you prevent Norovirus?

good hygeine

50

How is Hepatitis E transmitted?

fecal-oral

51

What is Hepatitis E associated with?

- E for Epidemic hepatitis
- contaminated water supply
- high mortality for fetus and mother

52

What are the characteristic of Reoviridae (respiratory enteric orphan)?

**dsRNA
- nonenveloped
- icodahedral

53

How is Rotovirus transmitted?

fecal-oral
(possibly respiratory)

- usually seasonally
-ubiquitous

54

Describe Rotavirus A and B.

Rota (wheel/spokes)

A - most common (90%) - infantile diarrhea with vomiting and fever

B - Adult onset of severe diarrhea (epidemic in Asia)

55

Describe the characteristics of Flaviviridae.

(+) ssRNA
Enveloped

56

What are two genus of Flaviviridae?

Flavivirus (Dengue virus)
Hepatitis C

57

How is Dengue virus transmitted?

Aedes aegypti (mosquito)

58

How does Dengue fever manifest with the 1st encounter? 2nd?

1st
- fever within 4-7 days post exposure
-severe headache
-severe joint and muscle pain
-nausea and vomiting
-rash, maculopapular

2nd Dengue hemorrhagic fever
-symptoms to classic dengue
-gingival and nasal bleeding
-increased menstrual flow
- GI bleeding
-hematuria

59

How is Dengue diagnosed?

ELISA serology (IgM, IgG) and antigens

tourniquet test

60

How do you manage Dengue virus?

-self-limiting
-control fever with antipyretics (avoid aspirin)
- use insect repellent
-no antiviral treatment
(no vaccine)

61

How is Hepatitis C transmitted?

blood

62

What damage is seen in the chronic state of HepC?

cirrhosis
end-stage liver disease
hepatocellular carcinoma

63

What is a symptom of HepC?

jaundice

64

What is the most common way Hep C is transmitted?

IV drug use (60%)
sex (15%)

65

Describe the characteristics of Togaviridae.

(+) ssRNA
Enveloped
icosohedral
enveloped "toga"

66

What two genus of Togaviridae?

Rubivirus (rubella)
Alphavirus (arboviruses)

67

How is Rubella virus transmitted?

contact with respiratory droplets

68

What are the symptoms in up to 70% of people infected with rubella?

asymptomatic

69

What are the clinical manifestations of rubella?

maculopapular rash - begins on face and spreads to trunk, then extremities
- rash fades after a few days
- occipital and post auricular lymphadenopathy

70

How do you prevent rubella?

MMR vaccine (12-18 months and dose 2 at 36 months)

71

Describe the consequences of Rubella during pregnancy?

During the viremic stage, the virus can cross the placenta.

Since Rubella can cross the placenta it can lead to congenital abnormalities, premature delivery and spontaneous abortion.

72

What infections are vertically transmitted?

TORCH

Toxoplasma gondii

Other infections (enterovirus, VZV, P-B19, HIV, Bacteria)

Rubella
CMV
HSV-2

73

Describe the characteristics of Filoviridae.

(-) ssRNA
enveloped
helical

74

What viruses are included in Filoviridae?

Ebola virus
Marburg virus
Cuevavirus (2011 Spain)

75

What are members of Filoviridae associated with?

hemorrhagic fever

(Ebola, Marburg)

*Dengue also can lead to hemorrhagic fever but is not part of this group

76

What are the signs and symptoms of Filoviridae?

Early: muscle aches, fever, vomiting, red eyes, skin rash

Acute: bleeding, skin hemorrhage

77

What are treatments for Filoviridae?

-NO FDA approved vaccine
-IV fluids and electrolytes
-maintain ventilation and perfusion
- manage infections

*antibodies may last up to 10 years

78

What are the characteristics of Orthomyxoviridae?

(-) ssRNA
enveloped (glycoproteins, antigenic variation)
segmented
-causes endemic and pandemic respiratory infections

79

Why is the characteristic of segmentation so important?

opportunity to mutate
mix gene segments

80

What are the three types of influenza and host?

Influenza A - humans, birds, swine (everything)
Influenza B - humans
Influenza C - mainly humans

81

Describe the structure of influenza and how it assists in entry of RNA into the host.

1. Hemoglutinens (HA) attach to sialic acid receptor found on respiratory epithelial cells of host.

2. The neuraminadase (NA) cleaves the sialic acid receptor and virus enters cell.

Matrix protein 2 (M2)- through envelope
Matrix protein 1 (M1)- on inside attached to ribonuclear protein

3. After entry, the whole virus is inside.

4. M2 will allow an H ion to enter the virion and cause dissociation of M1 and . ribonuclear protein.

5. H ion drops the pH and the envelope breaks.

6. (-) ssRNA is released.
7. Complementary copy made and then translated.

82

Which influenza type can undergo antigenic shift?

Influenza type A

83

Which influenza type can underdo antigenic drift?

All types
Influenza A, B, C

84

What is antigenic shift?

-substitution of gene segments with segments from another influenza virus (reassortment)
- only seen in type A
-pandemics
- less common

85

What is antigenic drift?

- small, constant point mutation
- gradual changed in aa composition
- minor antigenic change
- epidemics
- all three types
-annual vaccination

86

How is influenza named?

Nomenclature system:
Host origin
Geographic location
Strain number
Year of isolation
hemaglutinin and neuroaminidase subtypes

ex) A/California/7/2009 (H1N1)

87

How is Influenza transmitted?

person to person
direct contact
aerosol droplets
*infects respiratory epithelial cells

88

What is the incubation time for influenza?

1-4 days

89

What structure in Influenza is targeted by drugs?

M2 - matrix protein 2
neuroaminadase

90

What are the clinical manifestations of influenza?

fever
headache
chills
muscle aches
general fatigue
runny nose (as fever declines)
coughing (as fever declines)

Complications: Bronchitis, Pneumonia

91

What are treatments for influenza?

Zanamivir (Relenza) - targets neuroaminadase (A & B)
Oseltamivir (Tamiflu) - targets neuroaminadase (A & B)

Amantidine (target M2) - no longer recommended due to resistance

92

What is the recommendation for flu vaccine? method of delivery

yearly
flu shot - whole inactivated virus
Flumist - live attenuated

93

What are the characteristics of Paramyxoviridae

(-) ssRNA
enveloped

Matrix protein

G protein - mediates attachment to host cells

Fusion Protein (F) nfection of adjacent cells

94

What are two subfamilies of Paramyxoviridae?

ParamyxoviriNae

Pneumovirinae

95

What are two genus from the subfamily paramyxovirinae?

Rubulavirus (Mumps)

Morbilivirus (Measles)

96

How are mumps transmitted?

respiratory

97

Where does the mump virus replicate?

nasopharynx

98

What are the symptoms of mumps?

nonspecific myalgia
headache
parotitis (30-40%)

99

What are some complications of mumps?

orchitis (20-50) in post pubescent males
CNS involvement (15%)
pancreatitis (2-5%)
death

100

How would you prevent mumps?

MMR vaccine

101

How are measles transmitted?

respiratory droplets
nasal secretions

102

When are the measles highly contagious?

during prodromal period

103

What are the clinical signs of measles?

cough
coryza (rhinitis)
conjunctivitis (3Cs)
Koplic spots
high fever (40 C)
generalized maculopapular rash

104

What are complications of measles?

diarrhea
otitis media
pneumonia
encephalitis
death

105

How would you prevent measles?

MMR vaccine

** major cause of vaccine-preventable death in chldren

106

How is RSV transmitted?

droplets
fingers

107

What is the most common cause of LRI in infants and kids?

RSV