Respiratory Viruses I

Question 1

What is the most common route of viral infection?

Answer 1

Respiratory inhalation

Question 2

What is the genomic structure of influenza virus?

Answer 2

Negative RNA, segmented, enveloped

Question 3

Is influenza virus enveloped or not?

Answer 3

Enveloped

Question 4

What are the signs of influenza infection?

Answer 4

• Sudden fever
• Cough
• Nasal congestion
• Head and muscle aches
• Fatigue
• Diarrhea (often in infants)

Question 5

What is the main type of influenza virus causing disease in humans?

Answer 5

Type A

Question 6

What can be a devastating effect of influenza?

Answer 6

ARDS

Question 7

What viruses are destroyed by soaps?

Answer 7

Enveloped virions are destroyed by common hand soaps.

Question 8

What are the H and N in the influenza strains?

Answer 8

They are surface proteins.
H - hemagglutinin
N - neuraminidase

Question 9

How many RNA strands does influenza have?

Answer 9

8

Question 10

What protein allows influenza to adhere in the lungs?

Answer 10

Hemagglutinin

Question 11

Where does influenza replicate?

Answer 11

Nucleus - this is in contrast to other RNA viruses which are ALL in the cytoplasm (except influenza and retroviruses)

Question 12

What vaccines are available for influenza?

Answer 12

• Live-attenuated virus

- Killed virus

Question 13

How does antigen drift occur in influenza?

Answer 13

1. Influenza viruses replicate through RNA intermediates.
2. RNA-dependent RNA replication is error-prone.

Point mutations, usually in regions encoding HA antibody epitopes, can change virus structure and antigenicity leading to viruses that may cause epidemics. This is referred as “genetic drift”

Question 14

What can cause antigen shift and how is this different than drift?

Answer 14

Shifts are greater changes than drift.

RNA segment reassortment can change virus structure, antigenicity and function dramatically, leading to reassortant viruses that may cause pandemics. This is referred as “genetic shift”.

Question 15

Amantidine MOA

Answer 15

M2 is blocked and so RNAs will not release from virion proteins. Infection blocked at entry stage.

Question 16

Neuraminidase Inhibitor MOA

Answer 16

Inhibitor of neuraminidase which normally “unsticks” influenza viruses by cleaving sialic acids from infected cells and from visions - therefore inhibiting them prevents viral dissemination

Question 17

A cautious 43‐year‐old office worker decided to get vaccinated before the pending (2002‐2003) flu season. Her physician vaccinated her with an intramuscular dose containing: A\Panama (H3N2) and A\NewCaledonia/20/99 (H1N1) and B\Yamanashi. Four weeks after receiving the vaccine, the woman developed a high fever, myalgia, headaches, chills, and a dry, unproductive cough. The cough became progressive with the general symptoms lasting 3 weeks. Her doctor told her that she had the flu even though serological tests showed that the woman seroconverted and had a high vaccine antibody titer. Small changes in the surface glycosylation of the influenza virus are called which of the following?

A. Genetic shift
B. Genetic drift
C. Camouflage
D. Genetic reassortment
E. Point mutations

Answer 17

C. Camouflage

Question 18

What is the main disease caused by rhinovirus?

Answer 18

Common Cold

Question 19

What virus commonly causes conjunctivitis?

Answer 19

Adenovirus

Question 20

What does coronavirus cause?

Answer 20

Common Cold - often cause of croup, a bark like cough

Question 21

How do Ab protect against influenza infection?

Answer 21

The antibodies stick to the HA and prevent HA from binding cells, and/or prevent HA from catalyzing virus‐cell membrane fusion. The higher the affinity of the antibodies for critical parts of HA, the more effective they are at protecting the individual from infection.