Viral respiratory infections Flashcards Preview

Year 1 Microbiology > Viral respiratory infections > Flashcards

Flashcards in Viral respiratory infections Deck (86):
1

Upper respiratory pathogens replicate best at what temperature?

33-35 C

2

How can damage predispose patients to bacterial super-infections?

1. Interruption of mucociliary escalator2. Weaken immune system

3

What are symptoms of the common cold?

1. Rhinitis2. Pharyngitis3. NO high fever, LRT involvement, or respiratory distress

4

What is the peak seasonal incidence for the common cold?

Spring and Fall

5

What is the virology of rhinoviruses?

1. Picornavirus2. Non-enveloped3. +ssRNA4. Three types - A, B, C

6

Rhinoviruses are part of what family of viruses?

Picornavirus

7

Are rhinoviruses enveloped or non-enveloped?

Non-enveloped

8

What is the genome for rhinoviruses?

+ssRNA

9

How are rhinoviruses transmitted?

1. Direct contact with nasal secretions2. Large droplets 3. Contaminated fomites

10

What is the incubation period for rhinoviruses?

1-3 days

11

What is the pathogenesis of rhinoviruses?

1. 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

What is the virology of non-SARS coronaviruses?

1. Enveloped - glycoprotein coat 2. +ssRNA

13

What is the incubation period for coronaviruses?

3 days

14

Where do non-SARS coronaviruses replicate?

Epithelial cells of respiratory tract

15

Is there a vaccine for non-SARS coronaviruses?

No

16

What is the virology of adenoviruses?

1. Non-enveloped2. dsDNA genome3. Adenoviral fiber is toxic protein virulent factor 4. No seasonal pattern of illness

17

What adenovirus serotypes cause respiratory disease?

1, 2, 5

18

What are the transmission routes for adenoviruses?

1. Oral2. Droplet inhalation 3. Conjunctiva

19

Where do adenoviruses replicate?

Epithelial cells, cause damage there

20

Are adenoviruses enveloped or non-enveloped?

Non-enveloped

21

What is the adenovirus genome?

dsDNA

22

What is the adenovirus virulent factor?

Adenoviral fiber - toxic protein

23

How long can patients shed adenovirus virions following infection (without clinically apparent disease)?

6-18 months

24

Is there a seasonal pattern of illness for adenovirus?

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