SM_179a: Viral Infections Flashcards

1
Q

Which viruses infect the respiratory tract?

A
  • Influenza virus
  • Respiratory syncytial virus
  • Human metapneumovirus
  • Parainfluenza virus
  • Rhinovirus
  • Coronavirus
  • Adenovirus
  • Bocavirus

(other viruses utilize but do not infect the respiratory tract)

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2
Q

List the respiratory viruses and their family and genetic material

A
  • Influenza virus: orthomyxoviridae, (-)ssRNA, segmented
  • RSV: respiroviridae, (-)ssRNA
  • Metapneumovirus: respiroviridae, (-)ssRNA
  • Parainfluenza virus: paramyxoviridae, (-)ssRNA
  • Rhinovirusa: picornaviridae, (+)ssRNA
  • Coronavirus: coronaviridae, (+/-)ssRNA
  • Adenovirus: adenoviridae, dsDNA
  • Bocavirus: parvoviridae, (+/-)ssDNA
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3
Q

Pharyngitis is most commonly caused by ______

A

Pharynigitis is most commonly caused by adenovirus

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4
Q

Croup is most often caused by ____ and _____

A

Croup is most often caused by PIV1 and PIV2

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5
Q

Bronchiolitis is most commonly caused by ___

A

Bronchiolitis is most commonly caused by RSV

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6
Q

Pneumonia in adults is most commonly caused by ______

A

Pneumonia in adults is most commonly caused by influenza

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7
Q

_____ cause the common cold

A

Multiple viral pathogens cause the common cold

(rhinitis, nasal congestion, sneezing, pharyngitis, cough, hoarseness)

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8
Q

A respiratory virus is usually the cause of pharyngitis when there is associated _____

A

A respiratory virus is usually the cause of pharyngitis when there is associated nasal congestion

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9
Q

Croup is caused most often by ____ and symptoms arise from _____

A

Croup is caused most often by PIV1 and PIV2 and symptoms arise from inflammation and obstruction of the subglottic structures

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10
Q

Tracheobronchitis is characterized by a ______ and is caused by _____ and _____

A

Tracheobronchitis is characterized by a non-productive cough and is caused by influenza and PIV

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11
Q

Bronchiolitis is _____ characterized by _____ and is most commonly caused by _____

A

Bronchiolitis is viral infection of the terminal bronchiolar epithelial cells characteried by wheezing and nasal flaring and is most commonly caused by RSV

  • Edema and excessive mucus results in obstruction of small airways
  • Shortness of breath, increased work of breathing
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12
Q

Describe the classification of influenza

A

Influenza

  • A: humans, mammals, and birds - acquatic birds are main reservoir
  • B: severe disease in elderly and at risk, no pandemics
  • C: disease in children, most adults have protective immunity
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13
Q

Influenza A is characterized by _____ and _____

A

Influenza A is characterized by hemagglutinin and neuraminidase

  • Hemagglutinin (16 types): binds sialic acid, limits species transfer
  • Neuraminidase (9 types): viral release and propagation
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14
Q

Antigenic drift in influenza is ____ and is associated with _____

A

Antigenic drift in influenza is minor change based on mutations in genome RNA secondary to poor fidelity of RNA polymerase and is associated with epidemics

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15
Q

Antigenic shift in influenza is _____ and is associated with _____

A

Antigenic shift in influenza is a major change based on reassortment of segments of genome RNA and is associated with pandemics

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16
Q

H1N1 was a ______ reassortment

A

H1N1 was a quadruple reassortment

(Asian and European influenza, avian influenza, human influenza)

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17
Q

Describe the transmission of influenza

A

Influenza

  • Invades ciliated epitheial cells of upper respiratory tract
  • Spread via respiratory droplets and fomites
  • Droplets are large, travel short distances, and are viable for up to 24 hours on surfaces
  • Shed for 1-2 days prior to symptoms and up to 5 days after symptom onset
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18
Q

Common symptoms of influenza include _____, _____, _____, and _____

A

Common symptoms of influenza include fever, mylagias, sore throat, and non-productive cough

  • All symptoms not seen in all patients
  • Fever of abrupt onset
  • Severe cases present as pneumonia
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19
Q

Main complications of influenza are _____ and _____

A

Main complications of influenza are secondary bacterial pneumonia (Staph aureus and Strep pneumoniae) and exacerbation of cardiopulmonary conditions

(mortality rates higher in older age)

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20
Q

_____ is the preferred testing method for influenza

A

PCR identification is the preferred testing method for influenza

  • Clinical syndrome and rapid antigen detection can also be used
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21
Q

___ are NOT effective for treatment of influenza

A

M2 inhibitors (amantidine, rimantidine) are NOT effective for treatment of influenza

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22
Q

_____ used to treat influenza prevent virus release from the cell and have the effect of _____

A

Neuraminidase inhibitors (oseltamivir, zanamivir) used to treat influenza prevent virus release from the cell and have the effect of reducing symptoms by 24 hours and transmission by 24-48 hours

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23
Q

_____ used to treat influenza act by ____

A

Cap-dependent endonuclease inhibitors (Biloxivir) used to treat influenza act by stopping mRNA synthesis

  • About as effective as oseltamivir
  • One-time dose
24
Q

Which factor placed her at risk for severe respiratory distress from influenza infection?

A

Pregnancy

25
Q

Who should be treated for influenza?

A
  • Start within 48 hours of symptoms
  • Severe symptoms or anyone hospitalized
  • Higher risk for complications
  • < 19 years of age and receiving long-term aspirin therapy
  • Immunosuppressive conditions
26
Q

____ is a form of prevention for influenza virus

A

Influenza virus vaccine is a form of prevention for influenza virus (everyone should get it)

27
Q

RSV surface proteins are _____ and _____

A

RSV surface proteins are SH protein and F protein

  • SH protein: inhibits apoptosis
  • F (fusion) protein: mediates fusion of infected cells together to form syncytia
28
Q

_____ is the most common cause of lower respiratory tract infection in kids < 1 year old

A

RSV is the most common cause of lower respiratory tract infection in kids < 1 year old

(also large cause of neonatal death)

29
Q

RSV is transmitted by ____

A

RSV is transmitted by respiratory droplets

30
Q

RSV infection ______ and reinfection is common because _____

A

RSV infection remains restricted to the lung and reinfection is common because immunity does not persist

31
Q

RSV symptoms depend on _____ and _____

A

RSV symptoms depend on age and immunocompromised status

  • Older children and adults: rhinorrhea, nasal congestion, sore throat, cough, and fever
  • Infants and neonates: pneumonia or bronchiolitis, wheezing and apnea
  • Immunocompromised adults: viral pneumonia and secondary bacterial pneumonia
32
Q

Mainstay of RSV management is _____

A

Mainstay of RSV management is supportive

  • Passive immunity not recommended and benefit of ribavirin is unknown
33
Q

Parainfluenza virus ______ mediates ______

A

Parainfluenza virus fusion protein mediates the formation of multinucleated giant cells

34
Q

Describe the illness caused by the different types of parainfluenza virus

A
  • PIV 1 and 2: croup
  • PIV 3: children with lower respiratory tract disease (pneumonia)
  • PIV 4: common cold, pneumonia in immunocompromised people

(PIVn 3 is most common)

35
Q

PIV 1 and 2 cause _____ in children

A

PIV 1 and 2 cause croup in children

(high mortality in immunocompromised adults)

36
Q

PIV treatment is ______

A

PIV treatment is supportive

(no available antiviral has shown efficacy for therapy)

37
Q

Adenovirus has many _____, which allows it to cause many disparate diseases

A

Adenovirus has many antigenic serotypes (41), which allows it to cause many disparate diseases

  • Types 3, 4, 7, 21: respiratory disease
  • Types 8, 19: keratoconjunctivitis
  • Types 11, 21: hemorrhagic cystitis
  • Types 40, 41: infantile gastroenteritis
38
Q

Adenovirus is primarily transmitted via the _____ route

A

Adenovirus is primarily transmitted via the fecal-oral route

(also aerosol droplet and direct inoculation)

39
Q

Adenovirus causes ______, which is bilateral conjunctivitis followed by development of painful corneal opacities

A

Adenovirus causes epidemic keratoconjunctivitis, which is bilateral conjunctivitis followed by development of painful corneal opacities

40
Q

Adenovirus ___ causes sporadic outbreaks, which can be severe disease and pneumonia

A

Adenovirus 14 causes sporadic outbreaks, which can be severe disease and pneumonia

41
Q

Most adenovirus infections are _____, so treatment is reserved for those with severe disease

A

Most adenovirus infections are self-limiting, so treatment is reserved for those with severe disease

  • Severe pneumonia or other organ invasive disease are treated
  • Cidofivir: nephrotoxic
  • Brincidofovir
42
Q

Vaccine for _____ used by military, not civilians

A

Vaccine for adenovirus used by military, not civilians

(oral type 4 and 7 vaccine for military recruits)

43
Q

Rhinovirus has ____, which makes development of a vaccine difficult and explains why the common cold is so common

A

Rhinovirus has 100 serologic types, which makes development of a vaccine difficult and explains why the common cold is so common

44
Q

Rhinovirus is transmitted via ____ and _____

A

Rhinovirus is transmitted via respiratory droplets and contaminated hands or surfaces

45
Q

Rhinovirus replicates best at ____, so it prefers the _____

A

Rhinovirus replicates best at 32ºC, so it prefers the nose and conjunctiva

(replicates poorly at body temperature 37ºC, which is why it DOES NOT prefer the lower airway)

46
Q

There is ______ for rhinovirus

A

There is no specific therapy for rhinovirus

  • Symptom management
  • Vitamin C does not prevent common cold but may reduce symptoms
  • Zinc therapy may decrease symptoms
47
Q

Coronavirus is _____ and causes the _____

A

Coronavirus is ubiquitous and causes the common cold

(has been associated with lower tract disease but unclear if primary pathogen or co-pathogen)

  • Non-SARS serotypes include MERS-CoV and 2019-nCoV
  • SARS coronvirus: genome sequence different from existing human strains and binds to angiotensin-converting enzyme 2 receptor
48
Q

The source of his infection is _____ because he has _____

A

The source of his infection is a civet because he has SARS

49
Q

Hantavirus cardiopulmonary syndrome is ______

A

Hantavirus cardiopulmonary syndrome is initial fever followed by the abrupt onset of acute pulmonary edema and shock

50
Q

SARS-CoV is spread to humans from _____, which receive the virus from ______

A

SARS-CoV is spread to humans from palm civets, which receive the virus from bats

51
Q

MERS-CoV is spread to humans from _____, which receive the virus from ______

A

MERS-CoV is spread to humans from camels, which receive the virus from bats

(high mortality rate)

52
Q
A
53
Q

Most common signs and symptoms of 2019-nCoV are _____ and _____

A

Most common signs and symptoms of 2019-nCoV are fever and cough

(chest X-ray is best way to diagnose, most severe in males/older/those with comorbidities)

54
Q
A
55
Q

_____ is avian influenza A

A

H5N1 is avian influenza A

(could be very contagious in humans)