Respiratory Viral Infections

Question 1

Which virus has the following membrane proteins- Hemagglutinin, Neuraminidase, M2 and M1?

Answer 1

Influenza

Question 2

What is the function of the influenza M2 protein?

Answer 2

Virus Decoating

Question 3

Describe the genetic content of the influenza virus

Answer 3

8 RNA Segments

Question 4

Classes of influenza are based on sequence similarity of which proteins?

Answer 4

M1 and NP

Question 5

The subtypes of class A Influenza are based on which proteins?

Answer 5

HA and NA

Question 6

What are the influenza subtypes currently causing disease?

Answer 6

H1N1 and H3N2

Question 7

Gradual changes in genetic content based on point mutations is the basis of what process?

Answer 7

Antigenic Drift

Question 8

Antigenic Drift results in what?

Answer 8

Epidemic Influenza

Question 9

Sudden changes in HA and NA due to reassortment of class A influenza is the basis of what process?

Answer 9

Antigenic Shift

Question 10

What is responsible for pandemic influenza?

Answer 10

Antigenic Shift

Question 11

When is the peak of flu season?

Answer 11

Dec-March

Question 12

What is the transmission of influenza?

Answer 12

1. Airborne Droplets

2. Contaminated Surfaces

Question 13

What is the binding target of human influenza virus HA?

Answer 13

alpha2,6 Linked Sialic Acid

Question 14

What is the binding target of the avian influenza virus HA?

Answer 14

alpha2,3 Linked Sialic Acid

Question 15

Where is alpha2,3 SA found in humans?

Answer 15

Distal bronchiole epithelium and type II pneumocytes

Question 16

Where is alpha2,6 SA found in humans?

Answer 16

Tracheobronchial Epithelium and type I pneumocytes

Question 17

What is significant about pigs?

Answer 17

They express both receptors for human and avian flu and can serve as a mixing vessel for reassortment

Question 18

HA with a single basic AA in the cleavage site undergoes what? What is the result?

Answer 18

Extracellular cleavage; respiratory infection only

Question 19

HA with multiple basic AAs in the cleavage site undergoe what? What is the result?

Answer 19

Intracellular cleavage; systemic viral replication

Question 20

What is the role of NA?

Answer 20

To increase viral dissemination by facilitating the cleavage of sialic acid –> release of visions from infected cells –> prevent viral aggregation in extracellular space

Question 21

What infection is characterized by a dry cough, sore throat, nasal congestion and clear discharges with fever, HA and myalgias?

Answer 21

Influenza

Question 22

What are the complications of influenza?

Answer 22

1. Otitis Media
2. Sinusitis
3. Viral Pneumonia
4. Secondary Bacterial Pneumonia
   
   • S. pneumo, S. aureus, H. influenza
5. Reye’s Syndrome

Question 23

Describe the use of Amantadine and Rimantadine

Answer 23

Both are M2 Inhibitors (prevent decoating and thus replication) to be used early in influenza A infections

Question 24

What is the risk of Amantadine/Rimantadine?

Answer 24

Resistant Mutants

Question 25

What is the use of Oseltamivir and Zanamivir?

Answer 25

Inhibit NA for influenza A and B to reduce the risk of developing pneumonia

Question 26

What is the role of neutralizing antibodies in the influenza immune response?

Answer 26

They bind to HA to block infection. Inclues IgA, IgM and IgG - short lived and strain specific

Question 27

What is the role of Cytotoxic T Cells in the influenza immune response?

Answer 27

Target NP and M1 or surface glycoproteins to terminate viral replication. May cross react between subtypes and last for 4 years