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Microbial Diseases

Influenza Practice Questions

19 free Influenza practice questions for the Microbiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.

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Question 1 of 19 Medium

Which type of virus causes influenza in humans?

  1. A DNA virus
  2. B Retrovirus
  3. C RNA virus
  4. D Prion

Correct answer: RNA virus

Influenza viruses are single-stranded RNA viruses belonging to the Orthomyxoviridae family. Their segmented RNA genome allows genetic variation.

Question 2 of 19 Medium

Which glycoprotein of influenza virus is responsible for viral entry into host cells?

  1. A Neuraminidase
  2. B Capsid protein
  3. C Matrix protein
  4. D Hemagglutinin

Correct answer: Hemagglutinin

Hemagglutinin binds to sialic acid receptors on host cells, facilitating viral entry. It is also a major target for neutralizing antibodies.

Question 3 of 19 Medium

Which influenza virus type is responsible for pandemics?

  1. A Type A
  2. B Type B
  3. C Type C
  4. D Type D

Correct answer: Type A

Influenza A viruses infect multiple species and undergo antigenic shifts, leading to pandemics. These shifts result in new viral strains.

Question 4 of 19 Medium

What is antigenic drift in influenza viruses?

  1. A Major genetic reassortment of segments
  2. B Loss of the viral envelope
  3. C Complete viral genome replacement
  4. D Gradual mutation in viral genes

Correct answer: Gradual mutation in viral genes

Antigenic drift refers to small, gradual mutations in viral surface proteins. This leads to seasonal influenza outbreaks.

Question 5 of 19 Medium

Which antiviral drug inhibits neuraminidase in influenza virus?

  1. A Ganciclovir
  2. B Ribavirin
  3. C Zidovudine
  4. D Oseltamivir

Correct answer: Oseltamivir

Oseltamivir inhibits neuraminidase, preventing the release of new viral particles. It is commonly used in treating influenza infections.

Question 6 of 19 Medium

Which mode of transmission is most common for influenza?

  1. A Fecal-oral contamination
  2. B Vector-borne
  3. C Respiratory droplets
  4. D Blood transfusion

Correct answer: Respiratory droplets

Influenza spreads primarily through respiratory droplets when infected individuals cough or sneeze. Close contact facilitates transmission.

Question 7 of 19 Medium

Which symptom is most characteristic of influenza infection?

  1. A Persistent watery diarrhea
  2. B Erythematous skin rash
  3. C Bilateral joint swelling and pain
  4. D Sudden high fever and myalgia

Correct answer: Sudden high fever and myalgia

Influenza typically presents with sudden onset of high fever, muscle aches, and fatigue. These symptoms distinguish it from milder respiratory infections.

Question 8 of 19 Medium

Which influenza virus protein helps in the release of virions from infected cells?

  1. A Hemagglutinin
  2. B Capsid protein
  3. C Neuraminidase
  4. D Polymerase

Correct answer: Neuraminidase

Neuraminidase cleaves sialic acid residues, allowing newly formed virions to exit host cells. This facilitates the spread of infection.

Question 9 of 19 Medium

Which host cell receptor does influenza virus bind to?

  1. A Sialic acid receptor
  2. B CD4 receptor
  3. C ACE2 surface receptor
  4. D Integrin receptor

Correct answer: Sialic acid receptor

Influenza virus binds to sialic acid receptors on respiratory epithelial cells. This interaction is mediated by hemagglutinin.

Question 10 of 19 Medium

Which complication is commonly associated with influenza infection?

  1. A Secondary bacterial pneumonia
  2. B Peptic ulcer disease
  3. C Recurrent kidney stones
  4. D Hepatic cirrhosis and fibrosis

Correct answer: Secondary bacterial pneumonia

Influenza can damage respiratory epithelium, predisposing to secondary bacterial infections. Pneumonia is a common and serious complication.

Question 11 of 19 Medium

Which type of genome does influenza virus possess?

  1. A Non-segmented double-stranded DNA
  2. B Linear single-stranded DNA
  3. C Segmented single-stranded RNA
  4. D Circular single-stranded RNA

Correct answer: Segmented single-stranded RNA

Influenza virus has a segmented single-stranded RNA genome. This segmentation allows reassortment and antigenic shift.

Question 12 of 19 Medium

Which phenomenon leads to the emergence of new influenza strains with pandemic potential?

  1. A Antigenic shift
  2. B Antigenic drift
  3. C Gene deletion
  4. D Capsid mutation

Correct answer: Antigenic shift

Antigenic shift involves major changes due to reassortment of gene segments. It can create novel strains capable of causing pandemics.

Question 13 of 19 Medium

Which laboratory test is commonly used to detect influenza virus RNA?

  1. A ELISA
  2. B RT-PCR
  3. C Gram stain
  4. D Culture only

Correct answer: RT-PCR

RT-PCR (reverse transcriptase PCR) is a sensitive method used to detect influenza viral RNA. It allows rapid and accurate diagnosis.

Question 14 of 19 Medium

Which age group is at highest risk for severe influenza complications?

  1. A Young adults
  2. B Elderly individuals
  3. C Teenagers
  4. D Middle-aged individuals

Correct answer: Elderly individuals

Elderly individuals have weakened immune systems and are more susceptible to severe influenza complications. They are at higher risk of hospitalization and death.

Question 15 of 19 Medium

Which vaccine type is commonly used for influenza prevention?

  1. A Live attenuated bacterial vaccine
  2. B Inactivated viral vaccine
  3. C Recombinant DNA vaccine
  4. D Purified toxoid vaccine

Correct answer: Inactivated viral vaccine

Inactivated influenza vaccines are widely used to prevent infection. They stimulate an immune response without causing disease.

Question 16 of 19 Medium

Which influenza virus protein determines host specificity and immune recognition?

  1. A Matrix protein
  2. B Hemagglutinin
  3. C Polymerase
  4. D Nucleoprotein

Correct answer: Hemagglutinin

Hemagglutinin is responsible for binding to host cells and is a major antigen. Variations in this protein affect host range and immunity.

Question 17 of 19 Medium

Which influenza virus type infects both humans and animals such as birds and pigs?

  1. A Type A
  2. B Type B
  3. C Type C
  4. D Type D

Correct answer: Type A

Influenza A infects a wide range of hosts including humans, birds, and pigs. This zoonotic potential contributes to genetic reassortment.

Question 18 of 19 Medium

Which environmental factor increases influenza transmission?

  1. A High temperature and humidity
  2. B Cold and dry conditions
  3. C Direct sunlight exposure
  4. D High altitude

Correct answer: Cold and dry conditions

Influenza spreads more efficiently in cold and dry conditions. These conditions help viral particles remain stable in the air.

Question 19 of 19 Medium

Which structure surrounds the influenza virus and is essential for infectivity?

  1. A Capsule
  2. B Envelope
  3. C Cell wall
  4. D Flagella

Correct answer: Envelope

Influenza virus has a lipid envelope derived from the host cell membrane. This envelope contains glycoproteins essential for viral entry and release.

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