Viral respiratory infections Flashcards
1
Q
Upper respiratory pathogens replicate best at what temperature?
A
33-35 C
2
Q
How can damage predispose patients to bacterial super-infections?
A
- Interruption of mucociliary escalator2. Weaken immune system
3
Q
What are symptoms of the common cold?
A
- Rhinitis2. Pharyngitis3. NO high fever, LRT involvement, or respiratory distress
4
Q
What is the peak seasonal incidence for the common cold?
A
Spring and Fall
5
Q
What is the virology of rhinoviruses?
A
- Picornavirus2. Non-enveloped3. +ssRNA4. Three types - A, B, C
6
Q
Rhinoviruses are part of what family of viruses?
A
Picornavirus
7
Q
Are rhinoviruses enveloped or non-enveloped?
A
Non-enveloped
8
Q
What is the genome for rhinoviruses?
A
+ssRNA
9
Q
How are rhinoviruses transmitted?
A
- Direct contact with nasal secretions2. Large droplets 3. Contaminated fomites
10
Q
What is the incubation period for rhinoviruses?
A
1-3 days
11
Q
What is the pathogenesis of rhinoviruses?
A
- Infect ciliated mucosal epithelial cells 2. Virus enters cell, starts replicating, causes tissue damage3. Epithelial layer damage leads to vascular permeability and outpouring from lamina propria
12
Q
What is the virology of non-SARS coronaviruses?
A
- Enveloped - glycoprotein coat 2. +ssRNA
13
Q
What is the incubation period for coronaviruses?
A
3 days
14
Q
Where do non-SARS coronaviruses replicate?
A
Epithelial cells of respiratory tract
15
Q
Is there a vaccine for non-SARS coronaviruses?
A
No
16
Q
What is the virology of adenoviruses?
A
- Non-enveloped2. dsDNA genome3. Adenoviral fiber is toxic protein virulent factor 4. No seasonal pattern of illness
17
Q
What adenovirus serotypes cause respiratory disease?
A
1, 2, 5
18
Q
What are the transmission routes for adenoviruses?
A
- Oral2. Droplet inhalation 3. Conjunctiva
19
Q
Where do adenoviruses replicate?
A
Epithelial cells, cause damage there
20
Q
Are adenoviruses enveloped or non-enveloped?
A
Non-enveloped
21
Q
What is the adenovirus genome?
A
dsDNA
22
Q
What is the adenovirus virulent factor?
A
Adenoviral fiber - toxic protein
23
Q
How long can patients shed adenovirus virions following infection (without clinically apparent disease)?
A
6-18 months
24
Q
Is there a seasonal pattern of illness for adenovirus?
A
No
25
What is pharyngoconjunctival fever?
1. Caused by adenovirus 2. Conjunctivitis3. Phayngitis
26
What do adenovirus serotypes 40 and 41 cause?
Gastrointestinal disease
27
What other illnesses can adenoviruses cause?
1. Pharyngoconjunctival fever2. Croup 3. Bronchiolitis4. Pneumonia
28
What is the virology of coxsackieviruses?
1. Enterovirus subfamily of picornaviruses2. Non-enveloped 3. +ssRNA 4. Replication in cytoplasm 5. Can survive low pH of GI tract
29
What type of virus is coxsackievirus?
Enterovirus subfamily of picornaviruses
30
Is coxsackievirus enveloped or non-enveloped?
Non-enveloped
31
What is the coxsackievirus genome?
+ssRNA
32
Where does coxsackievirus replicate?
Cytoplasm
33
What is the most common virus responsible for herpangina?
Coxsackievirus (type A)
34
How is coxsackievirus transmitted?
Fecal-oral
35
Is there a vaccine for coxsackievirus?
No
36
What are the symptoms of herpangina?
1. Abrupt onset of fever 2. Small vesicle on soft palate that rupture to form white ulcers
37
What are the complications of herpangina?
1. Meningitis 2. Encephalitis
38
What are the characteristics of hand-foot-and-mouth disease?
1. Caused by coxsackievirus 2. Fever3. Vesicular lesions on soles of hand, feet, oral areas
39
What is presentation of croup?
1. Laryngotracheobronchitis 2. Swelling in the subglottic region of larynx 3. "Seal's bark" with possible inspiratory stridor 4. Differential diagnosis could be epiglottitis (HiB)
40
What are the treatments for croup WITH stridor at rest?
1. Oxygen2. Epinephrine 3. Glucocorticoids
41
What are the treatments for croup WITHOUT stridor at rest?
1. Humidified air2. Hydration
42
What is the etiology for croup?
Parainfluenza type 1 (most common)
43
What is the virology for parainfluenza virus?
1. Paramyxovirus2. Helical nucleocapsid 3. Enveloped with hemagluttinin and neuraminidase 4. -ssRNA 5. RNA synthesis occurs in cytoplasm
44
What family does parainfluenza virus belong to?
Paramyxovirus
45
Is parainfluenza virus enveloped or non-enveloped?
Enveloped with hemagluttinin and neuraminidase
46
What is the parainfluenza genome?
-ssRNA
47
Where does parainfluenza virus replicate?
Cytoplasm
48
What is the incubation period for parainfluenza virus?
2-10 days
49
What is the transmission route for parainfluenza virus?
Large droplets and direct contact
50
What is the pathogenesis for parainfluenza virus?
Infect and replicate in ciliated epithelium of respiratory tract
51
What is the definition of pneumonia?
Inflammation of the lung parenchyma leading to abnormal alveolar gas exchange
52
What is the most frequent cause of viral pneumonia in healthy adults?
Influenza A
53
What are the symptoms / characteristics of primary influenza virus pneumonia?
1. 1-4 days following influenza virus symptoms 2. Increased cough, tachypnea, dyspnea, acute respiratory distress3. Sputum Gram stain shows abundant PMN cells without significant number of bacteria 4. Chest radiograph shows bilateral, midlung, lower lung infiltration - diffuse
54
What is the virology of influenza virus?
1. Orthomyxovirus 2. Segmented, -ssRNA genome 3. Enveloped 4. Has hemagglutinin and neuraminidase
55
What family does influenza virus belong to?
Orthomyxovirus
56
What is the influenza virus genome?
Segmented, -ssRNA
57
Is the influenza virus enveloped or non-enveloped?
Enveloped
58
What is the function of hemagglutinin on influenza virus?
1. Attachment 2. Agglutinates RBCs
59
What is the function of neuraminidase on influenza virus?
1. Cleaves sialic acid to aid in: 2. Virion release and 3. Movement through mucus
60
What is the reason for needing to change influenza vaccines every year?
Antigenic drift
61
What is antigenic drift?
1. Small changes in H and N 2. Driven by point mutations made by the polymerase during replication 3. Epidemiologically significant changes every 2-3 years
62
What is antigenic shift?
1. Large changes in H and N 2. Driven by reassortment of two viruses (H and N proteins) 3. Co-infection of the same cell 4. Risk for pandemics
63
Which influenza type is capable of antigenic shift?
A
64
How do ion channel blocking antivirals work?
1. Blocks replication prior to genome release (M2 channel)2. Only effective against influenza type A 3. Examples - Amantadine and Rimantadine
65
How do neuraminidase inhibitors work?
1. Block neuraminidase enzyme of influenza A and B2. Reduced cell-to-cell and mucus spread 3. Must be given within 48 hours
66
What are the properties of Zanamivir?
1. Neuraminidase inhibitor 2. Oral administration
67
What are the properties of Oseltamivir?
1. Neuraminidase inhibitor 2. Oral administration
68
What are the properties of Peramivir?
1. Neuraminidase inhibitor 2. Intravenous administration
69
What are the properties of inactivated influenza vaccines?
1. Formaldehyde inactivated 2. IM and ID administration 3. > 6 months (IM), 18-64yo (ID)4. Trivalent or quadrivalent (IM), trivalent only (ID)
70
What are the properties of live attenuated influenza vaccines?
1. Intranasal inhalation 2. For healthy, nonpregnant persons 2-49yo3. Quadrivalent
71
What are the properties of recombinant influenza vaccines?
1. Made of hemagglutinin protein 2. IM administration 3. 18-49yo4. Trivalent
72
What are the advantages of recombinant influenza vaccine?
1. Rapid upscale of production2. Egg-free
73
What is the virology for SARS coronaviruses?
1. Coronavirus family 2. Enveloped 3. +ssRNA genome 4. More resistant to environment than non-SARS
74
What family does SARS coronavirus belong to?
Coronavirus family
75
Is SARS coronavirus enveloped or non-enveloped?
Enveloped
76
What is the SARS coronavirus genome?
+ssRNA
77
What is the route of transmission for SARS coronavirus?
1. Fecal-oral2. Close contact 3. Aerosol
78
What is the pathogenesis of SARS coronavirus?
1. Use angiotensin-converting enzyme 2 (ACE 2) as a receptor 2. Infects upper airway and alveolar epithelial cells, causing lung injury3. Spreads to other visceral organs and is detected in stool
79
What is the incubation period for SARS coronavirus?
2-10 days
80
What are the properties of bronchiolitis?
1. Expiratory wheezing 2. Nasal flaring 3. Air trapping4. Subcostal contractions5. Variable fever 6. Primary cause is RSV
81
What should be included as a differential diagnosis for bronchiolitis?
Allergic asthma and foreign body inhalation
82
What is respiratory syncytial virus?
1. Most common cause of bronchiolitis and pneumonia in children less than 1 year old 2. Paramyxovirus family 3. Enveloped 4. -ssRNA genome 5. Highly infectious
83
What is the treatment for RSV?
Ribavirin
84
What is the mechanism of action for Ribavirin?
1. Guanosine analog - inhibits nucleotide biosynthesis and mRNA capping; promotes hypermutation of genome 2. Indicated for severe LRT RSV infections in special populations such as: 3. Premature infants4. Patients with chronic lung disease 5. Patients with congenital heart disease 6. Immunocompromised patients
85
What agents are available for RSV immunoprophylaxis?
1. Palivizumab - chimeric human-mouse monoclonal anti-RSV Ab2. RSIG - pooled human Ig, enriched for anti-RSV Abs
86
What are the indications for RSV immunoprophylaxis?
1. Birth less than or equal to 32 weeks gestation 2. Age less than or equal to 2 years and therapy for chronic lung disease within 5mo preceding RSV season
