Q: Which equation best represents the relationship between the number of pandemic influenza deaths (D), the population size (P), and the mortality rate (M) as a percentage?

$$ D = P \times \frac{M}{100} $$

Question 1

Which structural feature of the influenza virus is responsible for binding to host cell receptors and facilitating viral entry?

Accepted Answer

Hemagglutinin (H) spike

Question 2

Influenza A viruses are classified into subtypes based on which two surface proteins?

Accepted Answer

Hemagglutinin (H) and neuraminidase (N)

Question 3

Which of the following best describes the primary mode of transmission for influenza viruses?

Accepted Answer

Aerosol droplets expelled during coughing or sneezing

Question 4

After initial infection, influenza virus first invades which part of the respiratory tract?

Accepted Answer

Upper respiratory tract (URT)

Question 5

Destruction of which cells by influenza virus increases susceptibility to secondary bacterial infections such as pneumonia?

Accepted Answer

Mucous and ciliated cells

Question 6

Which of the following symptoms is most characteristic of influenza compared to the common cold?

Accepted Answer

High fever (\$$ 102^\circ \mathrm{F} \leq T \leq 104^\circ \mathrm{F} \) $$with sudden onset

Question 7

Which diagnostic method is most likely to detect influenza virus during the early stages of infection?

Accepted Answer

Nasal swab sample with rapid test

Question 8

Why must antiviral drugs for influenza be administered within 48 hours of symptom onset?

Accepted Answer

To lessen symptoms by inhibiting viral replication before peak viral shedding

Question 9

Which of the following best explains why annual influenza vaccines are necessary?

Accepted Answer

Antigenic drift causes minor mutations in hemagglutinin and neuraminidase spikes

Question 10

Antigenic shift in influenza viruses is most likely to result in:

Accepted Answer

Gene reassortment leading to dramatic changes and major epidemics

Question 11

Which animal is considered a 'mixing vessel' for influenza viruses, facilitating gene reassortment and the emergence of pandemic strains?

Accepted Answer

Pig

Question 12

During the 1918 'Spanish flu' pandemic, which age group experienced the highest mortality rate?

Accepted Answer

Young adults (20-40 years)

Question 13

Which equation best represents the relationship between the number of pandemic influenza deaths (D), the population size (P), and the mortality rate (M) as a percentage?

Accepted Answer

$$ D = P 	imes \frac{M}{100} $$

Question 14

Which of the following statements about influenza B is correct?

Accepted Answer

It infects only humans and causes limited epidemics

Question 15

A patient presents with high fever, muscle soreness, and fatigue lasting several weeks. Which diagnosis is most likely based on the symptoms and duration?

Accepted Answer

Influenza

Question 16

Which of the following is NOT a recommended prevention strategy for influenza?

Accepted Answer

Antiviral drugs as routine prophylaxis for all individuals

Question 17

Which influenza subtype is primarily avian and has a high mortality rate in humans but limited human-to-human transmission?

Accepted Answer

H5N1

Question 18

If the interval between pandemics of a given influenza subtype is 68 years, and the last H2 pandemic occurred in 1957, in which year is the next H2 pandemic expected?

Accepted Answer

2025

Question 19

Which of the following best explains why influenza can cause widespread epidemics in both humans and animals?

Accepted Answer

It undergoes frequent antigenic drift and shift, allowing cross-species transmission

Question 20

Which equation would you use to calculate the incubation period (I) in hours if the onset of symptoms occurs 36-48 hours after exposure?

Accepted Answer

$$ 36 \leq I \leq 48 $$

Influenza Virus: Structure, Pathogenesis, and Clinical Features

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