Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infectious diseases pathophysiology > Influenza virus > Flashcards

Influenza virus Flashcards

1
Q

To chich virus family do influenza viruses belong?

A

Orthomyxoviridae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Mention the three types of influenza viruses.

A

A, B, and C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the common structural features of all three influenza virus types?

A
  • Host-cell-derived envelope
  • Envelope glycoproteins for entry and exit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of nucleic acid do influenza viruses have?

A

Segmented (8 segments), negative-sense, single-stranded RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are influenza A subtypes classified?

A

Based on two antigens:
* Hemagglutinin (H or HA)
* Neuraminidase (N or NA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are two common influenza A subtypes?

A

H1N1 and H3N2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

T/F. Influenza virus are enveloped.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

This is an attachment protein of the virus. Has the receptor binding site.

A

Hemagglutinin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

This is an enzyme thar removes terminal sialic acids from glycoproteins. Helps the virus exit infected cells and spread to new ones.

A

Neuraminidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the function of the M2 protein in influenza viruses?

A

Integral membrane protein (ion channel)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the function of the matrix (M1) protein in influenza viruses?

A
  • Provides structural support to the virion
  • Plays a key role in virus assembly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What proteins are bound to each RNA segment in influenza viruses?

A
  • Nucleoprotein (NP)
  • Polymerase proteins (PB1, PB2, PA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two non-structural proteins found in influenza-infected cells?

A

NS1 and NS2 (NEP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does HA bind to on the host cell membrane?

A

Sialic acid-containing receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the role of the M2 protein in influenza virus uncoating?

A
  • Acts as an ion channel
  • Allows H+ to enter the virion, facilitating uncoating
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where are influenza viral gene segments transported after entry into the host cell?

A

To the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the function of the polymerase complex (PB1, PB2, PA) in influenza replication?

A

It synthesizes positive-sense mRNA and negative-sense genomic RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What effect does the influenza virus have on host cell protein synthesis?

A

It disrupts host cell protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What process allows influenza viruses to produce different viral proteins from mRNAs?

A

Splicing of mRNAs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Fro where do influenza virions bud during their release from the host cell?

A

Lipid rafts on the cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What viral proteins are incorporated into the envelope of newly budded influenza virions?

A

HA, NA, and M2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

T/F. Influenza viruses are regularly associated with excess morbidity and mortality.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which influenza subtype is associated with the highest excess mortality?

A

H3N2, but H1N1 also contributes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What factors likely contributed to the decline in pneumonia and influenza hospitalizations from 1996 to 2011?

A

Vaccination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which age group has the highest attack rates of influenza?

A

Young individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which age group has the highest mortality rates from influenza?

A

Older adults, especially those over 65

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which age group of children is most affected by influenza?

A

Younger than 2 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are common secondary complications of influenza in children?

A

Otitis media and pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

An outbreak of influenza confined to a specific location (city, town, or country). This can be defined as…

A

Influenza epidemic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

When do influenza epidemics occur in temperate climates?

A
  • North: November to April
  • South: May to September
31
Q

What environmental factors contribute to influenza epidemic seasonality?

A

Temperature and humidity

32
Q

What behavioral factors may increase influenza transmission in colder months?

A

Indoor crowding and school attendance

33
Q

What are the three primary modes of influenza transmission?

A
  • Aerosol transmission
  • Droplet transmission
  • Surface contamination
34
Q

These are caused by the emergence of an antigenically variant influenza virus, to which the population has little or no prior immunity.

35
Q

It refers to the frequent changes in the antigenicity of the influenza virus.

A

Antigen variation

36
Q

Antigenic variation mainly involves changes in which two glycoproteins?

37
Q

This refers to minor antigenic changes that occur frequently within the HA and/or NA. Causes epidemics.

A

Antigenic drift

38
Q

What part of the influenza virus is primarily affected by antigenic drift?

A

Hemagglutinin

39
Q

What causes antigenic drift in influenza viruses?

A

Gradual accumulation of amino acid changes

40
Q

T/F. Antigenic drift reduces neutralization by antibodies generated against previous strains.

41
Q

It refers to major antigenic changes in the HA and/or NA of influenza A viruses. Caused by reassortment between two different strains of influenza viruses. Causes pandemics.

A

Antigen shift

42
Q

What is the result of an antigenic shift in influenza A viruses?

A

A new influenza virus (HxNx) enters the population, often leading to a pandemic

43
Q

What is the incubation period for influenza?

44
Q

What are the systemic symptoms of influenza?

A

Feverishness, chills, headache, myalgia, malaise anorexia, and sometimes prostration

45
Q

In children, where is myalgia (muscle pain) particularly prominent?

A

The calf muscles

46
Q

What eye-related symptoms can occur in influenza?

A

Severe eye muscle pain with lateral gaze, tearing, and burning

47
Q

What are the primary respiratory symptoms of influenza?

A

Dry cough, sever pharyngeal pain, and nasal obstruction or discharge

48
Q

What are the common physical exam findings in influenza?

A
  • Toxic appearance early in illness
  • Flushed face, hot and moist skin
  • Watery, reddened eyes
  • Clear nasal discharge
  • Hyperemic mucous membranes
  • Small, tender cervical lymph nodes
49
Q

What are the three main types of pneumonia associated with influenza?

A
  • Primary influenza viral pneumonia
  • Secondary bacterial pneumonia
  • Mixed viral and bacterial pneumonia
50
Q

What are some milder pulmonary syndromes that can occur with influenza?

A
  • Tracheobronchitis
  • Localized viral pneumonia
51
Q

Which individuals are at hichest risk for primary influenza viral pneumonia?

A

Those with cardiovascular disease

52
Q

What are the key symptoms of primary influenza viral pneumonia?

A

Fever, cough, dyspnea, and cyanosis

53
Q

What do chest radiographs show in primary influenza viral pneumonia?

A
  • Bilateral findings consistent with adult respiratory distress syndrome (ARDS)
  • No consolidation
54
Q

What do blood gas studies show in primary influenza viral pneumonia?

A

Marked hypoxia

55
Q

What are the hallmark symptoms of secondary bacterial pneumonia?

A

Cough, sputum production, and signs of consolidation

56
Q

What are the three most common pathogens causing secondary bacterial pneumonia after influenza?

A
  • Streptococcus pneumoniae
  • Staphylococcus aureus
  • Methicillin-resistant S. aureus (MRSA)
  • Haemophilus influenzae
57
Q

Where does the influenza virus attach and penetrated in the respiratory tract?

A

Columnar epithelial cells

58
Q

What three factors can block influenza virus attachment?

A
  • IgA
  • Mucoproteins
  • Mucociliary apparatus
59
Q

How does influenza inhibit host-cell protein synthesis?

A
  • Degradation of newly synthesized cellular mRNAs by endonuclease
  • Blocking translation of cytoplasmic mRNAs
60
Q

What viral protein contributes to protein degradation and cell death in influenza-infected cells?

A

PA protein

61
Q

What are the two primary mechanisms of cell death in influenza virus infection?

A

Necrosis and apoptosis

62
Q

In which respiratory cells does apoptosis commonly occur in influenza virus infection?

A

Bronchiolar and alveolar epithelial cells

63
Q

What viral factor induces apoptosis by poisoning mitochondria in influenza virus infections?

A

PB1-F2 protein of influenza A

64
Q

How is the Fas antigen involved in apoptosis during influenza virus infection?

A

Induced by double-stranded RNA during replication, triggering apoptosis

65
Q

T/F. Influenza virus cause a productive infection in peripheral blood mononuclear cells (PBMCs)?

66
Q

What cellular defects occur due to influenza infection in PBMCs?

A
  • Defects in chemotaxis and phagocytosis
  • Decreased proliferation and costimulation
67
Q

What are the bronchoscopic findings in typical acute influenza?

A

Diffuse inflammation of the larynx, trachea, and bronchi with mucosal injection and edema

68
Q

Key histological findings in influenza biopsies.

A
  • Vacuolization of columnar cells with cell loss
69
Q

How do individual cells appear histologically in influenza infection?

A

Shrinkage, pyknotic nucleus, and loss of cilia

70
Q

T/F. Most influenza cases are diagnosed based on clinical symptoms and seasonal epidemiology.

71
Q

Most widely used method for diagnosing influenza virus.

72
Q

This test detects viral antigens in respiratory secretions.

A

Rapid influenza diagnostic tests

73
Q

What are some drugs used to treat influenza?

A
  • Oseltamivir
  • Zanamivir
  • Perimivir

Infectious diseases pathophysiology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions