Question 1

Which glycoprotein on the influenza virus is primarily responsible for binding to host cells?

Accepted Answer

Hemagglutinin (H)

Question 2

What is the main function of neuraminidase (N) in the influenza virus life cycle?

Accepted Answer

Assisting viral budding and release

Question 3

Which process describes gradual changes in the amino acid composition of influenza glycoproteins due to constant genome mutations?

Accepted Answer

Antigenic drift

Question 4

During an antigenic shift, what occurs at the genetic level in influenza viruses?

Accepted Answer

A gene or RNA strand is substituted with one from another influenza virus of a different animal host

Question 5

Why does the influenza virus frequently evade the host immune response?

Accepted Answer

Its glycoproteins undergo frequent genetic changes

Question 6

Which influenza strain is most associated with pandemics and high virulence?

Accepted Answer

Influenza A

Question 7

What is a key difference between Influenza A and Influenza B regarding genetic variation?

Accepted Answer

Influenza A undergoes both antigenic drift and shift, while Influenza B only undergoes drift

Question 8

A patient presents with fever, headache, myalgia, and cough during flu season. Which diagnostic test would most rapidly confirm influenza infection?

Accepted Answer

Rapid immunofluorescence test for antigens

Question 9

Why is annual vaccination recommended for influenza?

Accepted Answer

Because the virus undergoes frequent antigenic changes

Question 10

Which antiviral drugs are currently recommended for treating influenza, considering resistance patterns?

Accepted Answer

Zanamivir (Relenza) and oseltamivir (Tamiflu)

Question 11

If a new influenza virus emerges from a bird and infects humans, which genetic event most likely occurred?

Accepted Answer

Antigenic shift

Question 12

What is the composition of the influenza virus genome?

Accepted Answer

10 genes on 8 separate RNA strands

Question 13

Which influenza strain is least likely to cause epidemics?

Accepted Answer

Influenza C

Question 14

A hospital is experiencing an outbreak of severe respiratory illness among elderly patients. Which influenza strain is most likely responsible?

Accepted Answer

Influenza A

Question 15

Which of the following best explains why influenza A can cause pandemics while influenza B cannot?

Accepted Answer

Influenza A undergoes antigenic shift, allowing for major genetic changes

Question 16

Which of the following is a plausible consequence of antigenic drift in influenza viruses?

Accepted Answer

Gradual decrease in vaccine effectiveness over time

Question 17

A patient is treated with amantadine for influenza but does not improve. What is the most likely explanation?

Accepted Answer

The virus has developed resistance to amantadine

Question 18

Which diagnostic method is used to screen for antibody titer against influenza?

Accepted Answer

Serological testing

Question 19

If $$N is $$the number of hemagglutinin subtypes and $$M is $$the number of neuraminidase subtypes, how many possible combinations of H and N exist for influenza A?

Accepted Answer

$$N 	imes M = 18 	imes 11 = 198$$

Question 20

Which of the following best describes the pathogenesis of influenza A in the respiratory tract?

Accepted Answer

Binds to ciliated cells, causes cell destruction and severe inflammation

Influenza Virus: Structure, Mutation, Strains, and Clinical Management

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