14. Respiratory Viruses

Question 1

How are respiratory viruses transmitted?

Answer 1

Droplets and fomites

Question 2

Which bacteria are transmitted via droplet spread?

Answer 2

Pertussis
Neisseria meningitidis
Group A strep

Question 3

Which viruses cause the common cold?

Answer 3

Coronavirus
Rhinovirus
Adenovirus

Question 4

How are influenza viruses classified?

Answer 4

Based on their core proteins

A, B and C

Question 5

What are the reservoirs of influenza viruses A, B and C?

Answer 5

A: Birds and mammals

B and C: confined to humans

Question 6

Which influenza virus is most commonly associated with outbreaks and epidermics?

Answer 6

A causes an epidemic seasonally
B causes one every 2-4 years
C is uncommon and associated with a milder disease

Question 7

What dictates the subtype of an influenza virus?

Answer 7

Haemaglutinin and neuraminidase

Question 8

What is antigenic drift?

Answer 8

Minor antigenic change due to errors in viral DNA polymerase

Results in yearly epidemics as population only has limited immunity

Question 9

What is antigenic shift?

Answer 9

Major antigenic change caused by genes being swapped from different strains

Question 10

What is the function of haemaglutinin?

Answer 10

Binds to receptors on host respiratory epithelial cells

Question 11

What is the function of neuraminidase?

Answer 11

Cleaves sialic acid in respiratory epithelium

Allows release of virus from the cell and prevents clumping

Question 12

How can an influenza infection cause a bacterial superinfection?

Answer 12

Inflammation of the trachea and bronchi leads to ulcerative necrotising trachea-bronchitis and loss of cilia

Question 13

What are the clinical features of influenza?

Answer 13

Abrupt onset of a fever, cough and myalgia

Persistent weakness and depression

Question 14

What time frame is someone infectious with influenza?

Answer 14

1-2 days before symptoms to 7 days after

Question 15

What percentage of people are asymptomatic with influenza?

Answer 15

30%

Question 16

What complications are associated with influenza?

Answer 16

Pneumonia
Secondary bacterial superinfection
Myositis/mycarditis
Reye’s syndrome

Question 17

What pathogens can cause bacterial superinfection after influenza?

Answer 17

Strep pneumoniae
H. influenzae
Staph aureus

Question 18

What is Reye’s syndrome?

Answer 18

Encephalopathy and liver failure after giving aspirin to children with a fever

Question 19

What is the treatment for influenza?

Answer 19

Supportive: analgesics, antipyretics
O2 if hospitalised
NA inhibitor antivirals

Question 20

Who should be vaccinated against influenza?

Answer 20

Anyone at high risk
Healthcare workers
All children 2-12

Question 21

What long term drug puts someone at higher risk for influenza?

Answer 21

Aspirin

Question 22

You can be reinfected with RSV. T/F?

Answer 22

True

Question 23

What part of the respiratory system does RSV damage?

Answer 23

Bronchioles

Question 24

What are the signs of RSV?

Answer 24

Respiratory distress: tachypnoea, nasal flare, wheeze
Apnoea
Irritability
Cyanosis
Prominent intercostal retraction

Question 25

What does intercostal retraction suggest?

Answer 25

Lower airway obstruction

Question 26

What is seen on a CXR in an RSV infection?

Answer 26

Flattened diaphragm and hyperlucent lower lung (hyperinflation)

Question 27

What immunity is given to those at high risk of RSV?

Answer 27

Palivizumab: passive immunity

Question 28

How many parainfluenza serotypes exist?

Answer 28

4

Question 29

What is the incubation time of parainfluenza?

Answer 29

3-6 days

Question 30

What diseases are caused by parainfluenza?

Answer 30

Croup | Bronchiolitis

Question 31

How are parainfluenza, RSV and influenza detected?

Answer 31

Multiplex PCR

Question 32

How many serotypes of adenovirus exist?

Answer 32

>50

Question 33

What diseases are caused by adenovirus?

Answer 33

Wide range of RTIs Diarrhoea Conjunctivitis

Question 34

What samples can be taken if a patient is suspected of having a respiratory virus?

Answer 34

Nasopharyngeal aspirates Throat swabs BAL Sputum

Question 35

Name 3 recent epidemics

Answer 35

Avian influenza SARS MERS-COV

Question 36

What animal served as a mixing vessel in avian influenza?

Answer 36

Pigs

Question 37

What animals were the reservoir hosts in MERS-COV?

Answer 37

Camels and bats

Question 38

What is the incubation period of COVID-19?

Answer 38

1-14 days | Median 5-6

Question 39

What are the common presentation of COVID-19?

Answer 39

Fever Cough SOB Lack of smell and taste

Question 40

What are other symptoms of COVID-19?

Answer 40

``` Myalgia Headache Sore throat Nasal congestion Vomiting Diarrhoea Fatigue ```

Question 41

Which patient groups are more likely to have less typical symptoms?

Answer 41

Elderly | Immunosuppressed

Question 42

What are the complications of COVID-19?

Answer 42

ARDS Thromboembolism Sepsis

Question 43

What are the risk factors for severe COVID-19?

Answer 43

>60 Underlying diseases Smoking

Question 44

How is COVID-19 diagnosed?

Answer 44

Nasopharyngeal and throat swab | RT-PCR for viral RNA (because SARS-COV-2 is an RNA virus, DNA must first be made to use PCR)

Question 45

What genes does RT-PCR look for in COVID?

Answer 45

E gene N gene RNA polymerase genes

Question 46

What cardiac sequelae may follow COVID?

Answer 46

Arrhythmias Myocardial injury Postviral myocarditis

Question 47

What factors might cause cardiac sequelae after COVID?

Answer 47

``` Virus itself Hypoxia ACE2 receptor downregulation Hypotension Inflammation Drug toxicity ```

Question 48

Who is at risk of acute kidney injury due to COVID?

Answer 48

``` elderly male CV disease Hypertension Chronic kidney disease ```

Question 49

How is 'long COVID' defined?

Answer 49

Symptoms longer than 3 weeks after first onset of symptoms

Question 50

Define chronic COVID?

Answer 50

>12 weeks after onset of symptoms

Question 51

What symptoms are associated with long/chronic COVID?

Answer 51

Ongoing cough, fever, fatigue, SOB | Psychiatric, cognitive and physical impairments