Major RNA Viruses Flashcards
1
Q
What are the 5 general properties that apply to RNA viruses?
A
- Enveloped/non-enveloped
- capsid symmetry
- nucleic acid (ss or ds)
- +/- sense, ambisense
- replication location (?)
2
Q
What is + sense RNA?
A
same RNA reading as host
3
Q
What is - sense RNA?
A
needs RNA polymerase
4
Q
What classification system is used to classify viruses?
A
Baltimore classification based on mRNA synthesis
5
Q
Which RNA virus is double stranded?
A
Reoviridae
6
Q
Which RNA viruses are nonenveloped?
A
Picornaviridae, Caliciviridaem Reoviridae
7
Q
Where do most RNA viruses replicate? exception?
A
cytoplasm
Othomyxoviridae, Retroviridae
8
Q
What class is a dsRNA?
A
Class III
9
Q
What class is a (+)ssRNA?
A
Class IV
10
Q
What class is a (-)ssRNA?
A
Class V
11
Q
What class is ssRNA-RT?
A
Class VI
12
Q
Describe the characteristics of picornaviridae?
A
+ssRNA
Nonenveloped
Icosahdral
resistant to pH 3-9
13
Q
Where does the picornaviridae replicate?
A
cytoplasm
14
Q
How is the picornaviridae classified?
A
Class IV
15
Q
What are 3 genus for picornaviridae?
A
Enterovirus
Rhinovirus
Hepatovirus
16
Q
What species are included in Enterovirus?
A
Poliovirus (1-3)
Coxsackie A (1-24)
Coxsackie B (1-6)
Enterovirus (68-71)
17
Q
How are most Enteroviruses transmitted?
A
fecal oral
18
Q
What cells are infected by the poliovirus?
A
oropharyngeal
intestinal mucosa
19
Q
What are the clinical manifestations of poliovirus?
A
90-95% remain subclinical 5-8% flu-like symptoms 1-2% associated with major manifestations: meningitis encephalitis paralytic poliomyelitis
20
Q
What are common viruses responsible for meningitis?
A
enterovirus coxsackie A&B echovirus Arbovirus HIV HSV-2
21
Q
What cells are involved in paralytic poliomyelitis?
A
cells of the anterior horn - results in flaccid paralysis
medulla - paralysis of the diaphragm»_space;>death
22
Q
What are the 3 types of paralytic polio?
A
spinal polio (paralytic) bulbar polio (muscle weakness) bulbospinal polio
23
Q
How would you diagnose poliovirus?
A
isolation of virus from stool
CSF (definitive)
24
Q
How would you treat polio?
A
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
