UR viral Flashcards
What is the temperature that upper respiratory viruses replicated?
33-35 C
What is the most common viral infection of the upper respiratory tract?
Rhinovirus
What are the symptoms of the common cold? What are not?
Rhinitis
Pharyngitis
No high fever, respiratory tract involvement
What is the incidence of colds?
2-3/year for adults, 6-8/yr for child
What are the three major complications associated with the common cold?
OM
Sinus infection
Asthma exacerbation
What should always be included in the dx for chronic upper respiratory tract infections?
Allergies
What are the four most common causes of the common cold in order?
- Rhinovirus (most)
- Coronavirus
- Other known
- Unidentified
Rhinoviruses are members of what family? What type of genome? What are the three viral species? Are they enveloped?
Picronavirus
+ssRNA
A, B, C
No envelope
How are rhinoviruses spread?
Respiratory secretions
How much virus is needed for inoculation?
Very small amount
What is the incubation period for rhinoviruses?
1-3 days
True or false: rhinoviruses do not exacerbate asthma or COPD?
False
What is the MOA of rhinovirus?
- attach to cilia
- disrupt epithelial cell layer
- fluid outpouring from the LP
What are the treatments for rhinovirus? When are abx indicated?
Symptom management
Abx only if there is an associated bacterial infx
Why is it hard to get immunity to rhinoviruses?
Over 100 serotypes
Is there any vaccine for rhinoviruses? If so, which serotypes?
No–too many serotypes
What is the genomic make up of corona viruses? Enveloped? Where do they replicate?
+ ssRNA
Enveloped.
Replicate in the epithelial cells of the upper respiratory tract
What is the optimal temp for Non-SARS coronaviruses? SARS one? What is the significance of this?
33-35 C for non
37 for SARS
This explains the differing symptoms
Transmission of the coronavirus through what?
Large droplets
What is the incubation period of coronavirus?
3 days
What is the treatment for infx with coronavirus? Is there a vaccine? If so, which serotypes?
symptomatic
No vaccine
What is the only common cold virus that has a DNA genome? Is it enveloped?
Adenovirus (dsDNA)
Non-enveloped
What is the surrounding halo around adenoviruses?
Toxins
What are the most common adenoviruses that cause respiratory disease?
1, 2, and 5
Individuals can shed adenoviruses for how long?
18 months
Where can adenoviruses survive where other viruses cannot? What is the significance of this?
Lymphoid tissue–allows a longer period to shed
Which of the upper respiratory tract viruses have no seasonal pattern of disease?
Adenovirus
What is the cause of pharyngealconjunctival fever?
Adenovirus
Serotypes 40 and 41 or adenovirus cause what diseases?
GI diseases
Are there vaccines to adenovirus? If so, for which serotypes?
yes, one for serotypes 4 and 7
What is the viral cause of croup, bronchiolitis, and penumonia?
Paravirus
Rhinoviruses infect which cells?
The ciliated mucosal epithelial cells.
Early in an infection with rhinovirus, nasal secretions are primarily due to what? Later?
Initially increased vascular permeability
Later d/t increase in lactoferrin, lysozyme, and IgA
The damage caused by viral infections and predispose patients to bacterial infections how? (2)
Interruption of mucociliary escalator
Weakened immune system
Why is it possible to get reinfected with a coronavirus?
We develop poor immunity to the virus
What is the treatment for infection with adenoviruses?
Symptomatic
Do you developed good immunity to adenoviruses?
Yes, but there are so many serotypes
What is the family of coxsackieviruses? Are they enveloped? What is their genetic material?
Subfamily of picornaviruses
Non-enveloped
+ssRNA
Where can coxsackie viruses survive, where other viruses cannot?
GI tract (can survive low pH)
What is the mode of transmission for coxsackie viruses?
Fecal-oral route
Are there vaccines available for the coxsackie virus? If so, which serotypes?
None
What is the prognosis for infection with coxsackie viruses?
Full recovery in a few weeks
What is the viruses that causes herpangina?
Coxsackie virus
What are the symptoms of herpangina? (2)
Abrupt fever
Small vesicles on soft palate.
What are the possible complications associated with herpangina?
Meningitis or encephalitis
What is the virus that causes hand-foot-and mouth disease? Symptoms? (2)
Coxsackie
Fever
Vesicular lesions on the soles of the hands, feet, and in oral areas.
What are all the viruses that cause the common cold? (6)
- Rhinovirus
- Non-SARS corona
- Adenovirus
- Coxsackie
- Parainflu (B &C)
- Respiratory syncytial virus
- Flu
What is the only common cold virus that is not caused by droplets?
Coxsackie
What is the only dsDNA virus that causes the common cold?
Adenovirus
What are the symptoms of croup? (3)
Fever, seal’s bark, inspiratory stridor
What is the prodrome for croup?
Rhinorrhea, mild cough, pharyngitis
What are the complications for croup?
Hypoxia
Why is croup more worrisome in children?
Smaller airway
What are the two things that should be in your differential when seeing croup?
- Obstruction
2. Bacterial epiglottitis
What is the treatment for uncomplicated croup?
Humidified air
What is the treatment for complicated croup?
Oxygen
Epi
Glucocorticoids
What is the test for differentiating between complicated and uncomplicated cases of croup?
Stridor at rest
What is the most common virus that causes croup?
parainfluenza (serotype 1)
The parainfluenza virus is from what family? Enveloped? Genome type?
From paramyxovirus fam
Helical nucleocapsid + envelop
-ssRNA
How is parainfluenza virus transmitted?
Droplets
What is the incubation period for parainfluenza virus?
2-10 days
In which cells does the parainfluenza virus replicate?
ciliated epithelium
How long does immunity against parainfluenza virus last?
Short lived
What are the major symptoms of the flu that are different from the common cold?
- Myalgias
- Shaking chills
- HA
- cough
What is the incubation period for the flu?
2 days
What is the biggest complication associated with the flu?
Pneumonia
Primary influenza virus pneumonia is caused by which flu strain?
A
What will you see in a patient’s sputum gram stain if they have viral pneumonia?
High PMNs, but no significant number of bacteria
What is the fatality rate of viral pneumonia?
50%
When in a flu infection do symptoms of pneumonia develop?
1-4 days following symptoms
What will a CXR reveal about viral pneumonia?
Diffuse interstitial infiltration
When do bacterial influenza associated pneumonias develop?
1 week after onset of symptoms
What are the causative agents of bacterial pneumonia? (3)
- Strep penumonia
- Staph aureus
- H. influenzae
Why are individuals who recently have been sick with a virus more likely to develop pneumonia?
Damage to the mucociliary escalator or respiratory epithelium
Compromised immune function
The flu is a member of what family of viruses? Is it enveloped? What is the genetic make up?
Orthomyxovirus family
Enveloped
Segmented -ssRNA
What are the proteins that the flu virus expresses? What does each do?
Hemagglutinin (attachment protein)
Neuraminidase (Cleaves sialc acid to aid in release)
What is antigenic drift? How does this apply to the flu? How does it happen?
Small changes in H and N proteins brought about by point mutations made by polymerase
What is antigenic shift? How does this apply to the flue? How does it happen?
Large changes in H and N proteins, driven by reassortment of two viruses (segment reassortment)
What is the cause of having to change the flu vaccine every year (antigenic shift or drift)?
Antigenic drift
How does segment reassortment occur?
Segments of two different viruses that have infected the same cell rearrange as new virions are formed
How many segments does the flu virus have?
7 - 8
How are the different hemagglutinin and neuraminidase protein variants distinguished from one another?
Different number (e.g. H3N2)
The flu virus is a - ssRNA virus. What does it need in it in order to carry out replication?
An RNA dependent RNA pol. (RdRp)
Where does flu virus reassortment occur?
In pigs (they’re called “mixing vessels”)
Which part of the flu virus are the dominant targets for antibodies?
Hemagglutinin and Neuraminidase
In viral naming (e.g. A/Texas/1/77/(H3N2), what does each component stand for?
A = serotype Texas = location 1 = isolate 77= year H3N2 = protein subtypes
What is the host range for influenza type A?
Humans, pigs, birds, other animals
What is the host range for influenza type B?
Just humans
What is the host range for Influenza type C?
Humans and pigs
What is the severity level for influenza type A, B, and C respectively?
A = severe B = sometimes severe C = mild
Which influenza type has the ability to cause pandemics? Epidemics?
Pandemics = A Epidemics = A and B
What is the only influenza strain that can undergo genetic shift?
A
For mild or uncomplicated cases of the flu, what is the determining factor on whether to treat with antivirals or not?
Based on risk factors for the patient
For a patient with no risk factors, when should you administer antivirals for the flu?
within 48 hours of onset
For a patient with risk factors, when should you administer antivirals for the flu?
Always
What are the ion channel blocking medications used for the flu? (2)
Amantadine
Rimatadine
What is the MOA of ion channel blockers?
block the viral M2 ion channel that is required for virus release
How long does the seasonal flu last?
about 1 week
When are the ion channel blocking antivirals used for the flu?
For type A, but not anymore d/t resistance
What are the three neuraminidase inhibitors?
Zanamivir
Oseltamivir
Peramivir
What is the MOA of neuraminidase inhibitors?
Neuraminidase
inhibitors block the neuraminidase enzyme of influenza A and B viruses, thereby reducing the
ability of the virus to spread from cell-to-cell
and to move through the mucus in respiratory
secretions.
What is the route of administration of zanamivir?
oral inhalation
What is the route of administration of oseltamivir?
Oral
What is the route of administration of peramivir?
IV
Neuraminidase inhibitors are effective against which flu strains?
A and B
What are the three varieties of flu vaccine?
Inactivated (IM)
Live attenuated
Recombinant flu
How are inactivated flu virus vaccines prepared? How are these administered?
“Killed” via formeldehyde
IM or ID
What is the age group that should get IM inactivated influenza vaccine?
Greater than 6 mo, including those with chronic medical disease
What is the age group that should get ID inactivated influenza vaccine?
18-64
What is the age group that should get live attenuated influenza vaccine?
healthy, non-pregnant 2-49 yo
What is the age group that should get IM recombinant influenza vaccine?
18-49
What is the route of administration for the live, attenuate virus flu vaccine?
Intranasal
What is the agent in the recombinant flu vaccine?
Hemagglutinin protein
What is the advantage of producing a vaccine from mammalian cells (MDMK)?
- Rapid scale up
2. Reduced likelihood of egg issues
What are the advantages of live attenuated vaccine?
IgG production, cell mediated immunity
How is the recombinant influenza vaccine made? Is this egg free?
a baculovirus is
reengineered to produce appropriate influenza
hemagglutinin (HA) proteins within cultured
insect cells.
This is egg free
Antiviral chemoprophylaxis is
indicated for whom?
high risk populations
What are the strains that are in the trivalent vaccines? quadravalent?
2 As and a B = trivalent
2 As and 2 Bs = quadraavalent
The SARS virus is from which family?
The coronavirus
What type of genetic material is in the SARS coronavirus? Is it enveloped?
+ssRNA
Enveloped
How is the SARS virus transmitted?
Fecal oral route
What is the incubation period for the SARS virus?
2-10 days
What are the symptoms of bronchiolitis? (3)
- Expiratory wheezing
- Nasal flaring/Subcostal retractions
- Variable fever
What is the more common cause of bronchiolitis and pneumonia in children <1 yo?
Respiratory syncytial virus (RSV)
RSV is from what virus family? Is it enveloped? What is the genetic material?
Paramyxovirus fam
Enveloped
-ssRNA
How is RSV spread? Incubation period? Duration?
Droplets
4-5 days incubation
2 weeks duration
What is the antiviral that can be used for RSV? What is the MOA?
Ribavirin
Guanosine analogue that promotes mutation of the viral genes
The F protein of RSV can lead to the
activation of what immune system protein?
TLR4
What are the two prophylactic treatments for RSV?
Palivizumab
RSIG = (IVIG)
What is the MOA of palivizumab? (what is it)
Monoclonal antibody to RSB
When is prophylaxis for RSV indicated?
Premature births
<2 yo with chronic lung disease
What is the route used for Ribavirin?
Aerosol
Once symptoms of RSV have begun, are RSIG or palivizumab effective in treatment?
No