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RNA Virus 1 Flashcards

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1
Q

RNA Viruses:
replicate in…
ds or ss?
special machinery requirements?

A

Replicate in cytoplasm (except influenza and retrovirus)

most ss RNA

(+) can be read like mRNA. Genome encodes for RNA-depedent RNAPolymerase

(-) require synthesis to (+) before viral proteins can be made… Virus particle contains RdRNAp

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2
Q

Naked viruses

A

Pico *
Calici *
Astro *
Reo *

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3
Q

Enveloped virus

A 
Toga *
Flavi *
Bunya
Arena
Rhabdo
Paramyxo
Corona
Filo
Retro
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4
Q

Enterovirus disease

A
  • Vesicular disease / aseptic meningitis
  • gastrointestinal disease
  • respiratory disease
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5
Q

Arbovirus diseases

A

encephalitis and hemorrhagic fever

spread by arthropods

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6
Q

PicoRNAvirus:

types

A

Enterovirus
Hepatovirus
Rhinovirus

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7
Q 
Picornavirus:
genome (ss/ds, +/-)...
envelope?
capsid...
attachment...
replication...
release...
A
  • Single strand
  • Positive sense
  • Naked (no envelope)
  • Icosahedral capsid of 60x non-glycosylated proteins
  • attach/entry via receptor-mediated endocytosis
  • replicate in cytoplasm
  • release by lysis
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8
Q

Picorna attachment

A

cell receptors part of IG superfamily (binds to canyon region on vertices of virus)

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9
Q

receptor for Polio attachment

A

PVR/CD155

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10
Q

receptor for rhinovirus and several coxsackievirus

A

ICAM-1

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11
Q

Picornavirus replication scheme

A

One polyprotein is translated and then cleaved by viral protease.

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12
Q

Picornavirus transmission

A

Transmitted via fecal-oral and respiratory secretions

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13
Q

Picornavirus disease

A

Enterovirus (10-15mil/yr)

Rhinovirus (mils/yr) — most common cause of common cold

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14
Q

Rhinovirus pH/temp optimums

A 
acid labile (neutral better)
Topt = 33*C (cooler in the nose)
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15
Q

Enteroviruses / HepA

pH/temp optimums

A 
Acid resistant (pH 3-9)
also resistant to detergents, heat, mild sewage treatment
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16
Q

Where do enteroviruses replicate?

A

mucosa and lymphoid tissues GI tract… causes viremia

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17
Q

Enterovirus primary and secondary viremia patterns

A

1* viremia spreads virus to target tissues

2nd phase of viral replication occurs at targets, resulting in 2* viremia and SYMPTOMS

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18
Q

Poliovirus infections symptoms

-where does it infect?

A
  • mostly asymptomatic
  • symptoms range from mild fever / diarrhea to flaccid paralysis
  • 2% aseptic meningitis
  • 1% permanent paralysis
  • infects:
    ant. horn cells of spine
    motor cortex of brain
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19
Q

Poliovirus vaccination

A

-three serotypes covered

  • Inactivated Polio Vaccine (IPV) - killed
  • Oral Polio Vaccine (OPV) - live attenuated

-only IPV used in US since 2000

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20
Q

Coxsackie A virus diseases

A

aseptic meningitis
herpangina
hand, foot and mouth disease
conjunctivitis

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21
Q

Coxsackie B virus diseases

A

aseptic meningitis
myocardial and pericardial infections
pleurodynia

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22
Q

Echovirus diseases

A

aseptic meningitis (outbreaks every summer)

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23
Q

Parechovirus diseases

A

respiratory
gastrointestinal
encephalitis (rare)
myocarditis (rare)

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24
Q

Kobuvirus disease

A

gastrointestinal

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25
What characterizes enterovirus vesicular disease?
Hand foot and mouth disease (papular skin rash) | Herpangina (blister-like sores in mouth)
26
What are most common causes of vesicular disease
Coxsackie A16 | Enterovirus
27
treatment for enterovirus vesicular disease
only symptom relief
28
diagnose enterovirus vesicular disease
typically clinical
29
when is enterovirus meningitis most common
summer / early fall
30
most common / other causes of viral meningitis
``` ** Enterovirus Mumps Herpesviruses (EBV, HSV, VSZ) Measles Influenza Arbovirus LCMV ```
31
Symptoms of viral meningitis in infants and young adults
fever irritability poor eating hard to awaken
32
Symptoms of viral meningitis in adults
``` high fever severe headache stiff neck sensitivity to bright light sleepiness / trouble rousing nausea vomiting lack of appetite ```
33
viral meningitis time course and recovery
usually last for 7-10 days - recover normally
34
treatment for viral meningitis
nothing specific... supportive care
35
diagnosis for viral meningitis
detection of virus particles | serology (retrospective)
36
What about Entervirus 68? disease... virus particles found... transmitted...
Entervirus respiratory disease... symptoms with wide range of severity virus found in respiratory secretions (saliva, mucus, sputum) spread by sneezing / coughing, and fomites
37
Other manifestations of enterovirus | besides respiratory / meningitis / vesicular
``` viral conjunctivitis (cox A, entero 70) myocarditis pericarditis encephalitis paralysis ```
38
Diagnose Enterviruses | methods
PCR (RT-PCR) for virus in tissues Virus isolation / culture Serology (acute & convalescent) is helpful
39
Diagnose Enteroviruses | limitations
sensitivity... viremia undetectable at time of symptoms (viremia occurs first) CSF specimen during acute phase are sometimes negative
40
Treatment for enterovirus
supportive care
41
Principle agent of common cold
Rhinovirus
42
Rhinovirus binds to ____ on cell surface
ICAM-1
43
Where does Rhinovirus infect?
upper respiratory tract
44
Why is reinfection with rhinovirus so common
IgA immunity is short-lived | More than 100 independent serotypes of Rhinovirus
45
Rhinovirus incubation period and acute symptom timeline
1-2 days of incubation | 3-7 days of acute symptoms
46
Treatment for Rhinovirus
nothing specific no good vaccine *possible block of receptor attachment
47
``` HAV: Transmission: 1* Replication site: Virus particles excreted (when): Spreads to: ```
Hepatitis A Virus Fecal-Oral transmission Initial replication in enteric mucosa Virus excreted in feces BEFORE symptoms Spreads to liver w/ 2* viremia
48
HAV incubation
15-45 days | "short incubation"
49
``` HAV Early Symptoms (Prodrome) ```
``` fever nausea anorexia abdominal pain (RUQ) dark urine clay-colored stool ```
50
HAV | Icteric phase symptoms
jaundice pruritis (itching) enlarged / tender liver (3-4 weeks)
51
HAV | Fulminant infection
Rare develop rapidly lead to severe / life-threatening liver failure
52
Diagnose HAV - clinical - lab
Clinically - elevated ALT - jaundiced Lab - positive IgM anti-HAV
53
Is HAV commonly cause a chronic or acute disease?
acute common... lasting 3-6 months
54
Other causes of viral hepatitis (besides HAV)
CMV EBV Coxsackie virus
55
Other causes of hepatitis (besides viral)
``` Toxoplasmosis (and other inf) Drugs, alcohol Cholescystitis Pancreatitis Autoimmune disease ```
56
HAV vaccination is recommended for:
- international travelers - Men having sex with men - drug users
57
HAV vaccination form (inactive, dead, etc)
- inactivated whole virus | - it's a cell culture adapted, inactivated with formalin
58
What is twinrix?
The HAV and HBV mixed vaccine
59
When should HAV-Ig be administered to patient living with someone who's Hep-A infected
within 2 weeks of last exposure | 80-90% effective at preventing clinical Hep-A
60
RNA viruses that cause gastroenteritis
calicivirus astrovirus rotavirus (reovirus family)
61
Two main factors contributing to wide-spread transmission of viruses causing gastroenteritis
- large quantities of virus are shed in the stool | - virus is resistant to the environment
62
Calicivirus: genome (ss/ds, +/-)... envelope? capsid...
- positive sense, single strand genome - naked - single icosahedral capsid
63
Norovirus is the primary agent responsible for ____
most acute diarrheal disease - cruise ships - day care centers (90% of all viral gastroenteritis)
64
Norovirus named from
Norwalk strain (Norwalk, ohio)
65
How many genogroups?
five (G-I to G-V) | GII.4 is predominant
66
Norovirus transmission
Fecal-oral contaminated food fomites aerosol (vomiting)
67
How are virus particles spread?
high levels shed in diarrhea and vomitus
68
Norovirus only requires ____ for infection
10 virus particles
69
Norovirus incubation time
24-48 hours
70
Norovirus pathogenesis
- GI infection leads: - maldigestion / accumulation of carbs - malabsorption of nutrients - inhibition of water absorption - mucosa remains intact
71
Treat Norovirus
supportive care | - recovery usually complete
72
Diagnose Norovirus
- RT-PCR - sequencing for genotype determination - - rapid enzyme immunoassay - poor sensitivity - - cannot be grown in cluture
73
Astrovirus genome (ss/ds, +/-)... envelope? capsid...
- positive sense, single strand genome - naked - single icosahedral capsid
74
What does astrovirus look like on TEM
star-shaped
75
Astrovirus is associated with _____, particularly in children
mild gastroenteritis outbreaks
76
Astrovirus in acid / heat...
Acid-stable | Heat-resistant
77
How is astrovirus cultured?
It's cannot be cultured, dummy!
78
Reovirus | important types
Rotavirus | Colorado Tick Fever
79
``` Reovirus: genome (ss/ds, +/-, circular/segmented)... envelope? capsid... nucleocapsid... ```
- segmented, double-strand RNA genome - icosahedral capsid - naked - nucleocapsid has three concentric shells, surrounding 11 segments of ds RNA
80
What is the leading cause of severe acute gastroenteritis among children worldwide
Rotavirus
81
What are the main antigenic determinants of Rotavirus
VP7 and VP4
82
What is the name of the protease-cleaved protein on the rotavirus capsid?
VP4 (P protein)
83
What is the name of the glycoprotein on the rotavirus capsid?
VP7 (G protein)
84
how many serotypes are there for rotavirus?
5 strains (G1-G4, G9), based on capsid antigens
85
How is rotavirus transmitted?
Fecal-oral route | Highly contagious
86
Is the rotavirus particle stable?
You better believe it
87
When do rotavirus infections typically occur in the US
Late fall - early spring
88
Rotavirus: replication site incubation
- replicates in villous epithelium of small intestine | - incubation 1-3 days, followed by abrupt disease onset
89
Describe Rotavirus infection.
It's localized, causing decreased intestinal absorption of glucose, water and sodium.
90
What are the symptoms of Rotavirus?
- Vomiting - abdominal cramps - low-grade fever - frequent, copious, watery stools
91
Treat Rotavirus
supportive | rehydration, electrolytes
92
Most severe cases of Rotavirus occur in which population?
infants and children | severe diarrhea
93
Diagnose Rotavirus
detection of viral particles and antigens in stool. | Rapid antigen detection test
94
What are the two rotavirus vaccines? Method of delivery? Live/dead? Only for whom?
RotaTeq and Rotarix Oral administration Live virus only for Infants
95
RotaTeq...
[RV5] | pentavalent human-bovine Reassortment Rotavirus Vaccine
96
Rotarix
[RV1] Monovalet Human Rotavirus Vaccine
97
Rotavirus hazard
Intussusception --- bowel blockage from folding back onto itself.
98
Colorado Tick Fever disease characterized by
acute disease with fever, headache, sever myalgia
99
Colorado Tick Fever is caused by what agent?
Reovirus
100
Describe the Reovirus genome
12 ds RNA segments
101
``` Hepatitis E virus genome (ss/ds, +/-)... envelope? capsid... incubation... mode of transmission... ```
- positive sense, single strand RNA - naked - icosahedral capsid - avg 40 days / range 15-60 days - Fecal-Oral transmission
102
What is the natural host of HEV?
Humans
103
What's the major cause of acute hepatitis worldwide?
HEV
104
Incidence of HEV in the US? (high or low)
Low
105
How does HEV disease present?
frequently subclinical... acute disease may fulminate... 15-25% in pregnant women.
106
In which groups is HEV common?
common in adolescents and pregnant women.
107
How does HEV present in children?
children usually have mild or no symptoms
108
HEV risk factors
Poor sanitation (fecal-oral)
109
HEV prevention
drink clean water
110
Treat HEV
hydrate or die
111
Diagnose HEV
IgG detection (not routine)

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