Lecture 18

Question 1

What is otitis media?

Answer 1

When the inner and middle ear become infected with respiratory vriuses leading to bulging of the ear drum

Question 2

What is the appearance and purpose of respiratory epithelium?

Answer 2

Ciliated to sweep mucus containg pathogens out of the respiratory tract and into the GI tract where it can be destroyed by the low pH of the stomach

Question 3

How is the size of droplets produced by coughing important?

Answer 3

Small droplets will remain in the air for a long time and may penetrate right down to the alveoli meaning that they can cause infection in upper and lower airways while large droplets will settle faster and be deposited in the upper airways causing infection there

Question 4

What are the recognition molecules for three types of respiratory virus?

Answer 4

Influenza Virus: Sialic acid
Respiratory Syncytial Virus: Herapin-like glycosaminoglycan
Rhinovirus: Intracellular adhesion molecule 1

Question 5

What is the relevance of the receptor molecules for respiratory viruses?

Answer 5

They can provide drug targets

Distribution of receptors on the airways differs and can modify where the virus can cause infection

Question 6

What causes damage in the pathogenesis of the influenza virus?

Answer 6

The budding out of the newly made virus particles in the cell can damage the cell leading to loss of function and thickening of airways

Question 7

How can damage to the epithelial lining of the respiratory tract cause damage?

Answer 7

The loss of normal respiratory epithelium can lead to mucous build up as the cilia are unable to sweep the mucus away
The presence of necrotic material increases the viscosity of the mucous
Tissues swell potentially obstructing airways

Question 8

Why are respiratory illness’ more severe in infants and elderly?

Answer 8

Young children have small airways making them susceptible to blocking
Elderly people often have airways which already contain much damage

Question 9

How many colds will children and adults experience each year on average?

Answer 9

4/year for adults and 8/year for children

Question 10

How common is influenza?

Answer 10

15%/year

Question 11

How common is bronchioltits due to RSV?

Answer 11

1-2% In children aged 1-3 years

Question 12

What is the frequency of Upper respiratory illness compared to to other ailments?

Answer 12

5.5%

Question 13

What is the frequency of Acute Bronchitis compared to other ailments?

Answer 13

5.4%

Question 14

What is the frequency of Otitis media compared to other ailments

Answer 14

4.9%

Question 15

What is the frequency of tonsilitis compared to other ailments?

Answer 15

3.9%

Question 16

What are the bacteria which are the common cause of respiratory illnesses?

Answer 16

S.Pneumonia
Haemophilus influenzae
Moraxella Catarrhalis
S.Pyogenes

Question 17

What are the viruses that are the common causes of respiratory illnesses?

Answer 17

Rhinovirus
Coronaviruses
Respiratory Syncitial Virus
Inflenza Virus

Question 18

Which infections of the respiratory tract are almost always due to viruses?

Answer 18

Colds
Bronchitis
Pharyngitis
Influenza

Question 19

What are the structural features of the influenza virus?

Answer 19

Segmented genome of 8 RNA molecules

Surface proteins Neuraminidase, Haemagluttinin

Question 20

What is the role of Haemagluttinin in influenza?

Answer 20

Binding to sialic acid to allow for cell invasion

Question 21

What is the role of Neuraminidase in influenza?

Answer 21

To cleave the link between sialic acid and the virus to free it so it can go and infect other cells, this activity can be impaired by tamiflu as it is a neuraminidase inhibitor

Question 22

What is the most well known influenza pandemic and is it the first pandemic?

Answer 22

The pandemic of 1918-19 is the most famous however there have been pandemics of influenza since the 17/16 hundreds
1918/19 was significantly large
1918/19 virus regarded as first virus there fore its haemagluttinin and Neuraminidase are typed as class one

Question 23

Why was the pandemic of 1918/19 so bad?

Answer 23

It introduced a new strain of influenza, where people did not have antibodies to haemagluttinin 1

Question 24

How many types of the surface proteins of influenza exist?

Answer 24

Neuraminidase types 1-9

Haemagluttinin types 1-16

Question 25

What are the two causes of genetic change in the influenza virus?

Answer 25

Drift which is a gradual accumuluation of mutations resulting in only minor changes Shift which is an abrupt reassortment of genes resulting in major changes

Question 26

What was the incidence of influenza in Maori in the 1918/19 epidemic?

Answer 26

10% In Maori men 30-40 | 5% in Maori Women 30-40

Question 27

How long does influenza illness last?

Answer 27

5-6 Days with 3-4 days of bedrest, morbidity and mortality typically only seen in the very old or young Illness is experienced approximately every 7 years

Question 28

What are the striking features of influenza?

Answer 28

Abrupt onset, fever, chills, headaches, myalgia, malaise | Dry cough, pharyngeal pain, nasal discharge, recovery with immunity

Question 29

What is myalgia?

Answer 29

Muscle aches

Question 30

What is malaise?

Answer 30

Feeling unwell

Question 31

How is influenza diagnosed?

Answer 31

Typically just the clinical symptoms are used, however serological tests, PCR looking for influenza genome, cell cultures

Question 32

How soon do antibodies to influenza appear?

Answer 32

10-14 Days if a new infection

Question 33

What are the two treatments for influenza?

Answer 33

Oseltamivir or tamiflu and a annual vaccine which anticipates drift in current strains (70-80% Effective)

Question 34

What are the key features of respiratory syncytial virus?

Answer 34

RNA virus similar to meales and mumps Adjacent infected cells will merge to form a syncytia 60% of children will be infected in their 1st year while 100% have been infected by their 3rd year

Question 35

Where does RSV affect?

Answer 35

Any part of the airway and the middle ear

Question 36

What illness is caused by RSV?

Answer 36

Bronchiolitis (croup) is the most common disease where the child becomes wheezy and breathless for the first few days as the inflammation of the bronchioles increases the resistance to airflow

Question 37

How is Bronchiolitis treated?

Answer 37

Corticosteroid therapy can have some benefits, otherwise there is no vaccine or antiviral treatment

Question 38

What family of rhinoviruses cause and what disease do they typically cause?

Answer 38

Picornaviruses which cause colds

Question 39

What are the features of rhinoviruses?

Answer 39

Very small RNA virus 99 Serotypes Replicates best at temperatures in upper airways not lower airways

Question 40

What is the epidemiology of rhinoviruses?

Answer 40

Transmitted by respiratory droplets and contaminated surfaces Incubation period of 1-4 days Infection of nose and sinuses Nasal mucous, sneezing, cough, sore throat, minor fever, muscle aches Recovery takes 1-2 weeks

Question 41

How does an individual recover from rhinovirus infection?

Answer 41

Recovery with long lasting immunity to that serotype Symptomatic treatment No effective antiviral treatment No effective vaccine