Virus Quiz : Test your knowledge

1. Which of the following best describes a “non-enveloped” virus?

1. A virus that lacks any protein coat.
2. A virus composed only of proteins with no nucleic acid.
3. A virus whose outermost layer is the protein capsid without a lipid membrane.
4. A virus that cannot infect animal cells.

2. With reference to viral receptors on host cells, which of the following statements is/are correct?

1. They are normal host molecules that viruses exploit for entry.
2. They are synthesized only when a virus infects the cell.
3. They partly determine the tissue tropism of a virus.

Select the correct answer using the code below:

1. 1 only
2. 1 and 3 only
3. 2 and 3 only
4. 1, 2 and 3

3. Which of the following is the primary target of most neutralizing antibodies against viruses?

1. Viral lipid envelope only
2. Viral nucleic acid inside the capsid
3. Viral surface proteins involved in attachment and entry
4. Host cell receptors

4. Consider the following statements regarding arboviruses (arthropod-borne viruses):

1. They all have vertebrate hosts and arthropod vectors.
2. Transmission usually requires a bite from an infected arthropod.
3. They can never be transmitted by blood transfusion.

Which of the statements given above is/are correct?

1. 1 and 2 only
2. 2 and 3 only
3. 1 and 3 only
4. 1, 2 and 3

5. The phenomenon where a previously infected individual experiences more severe disease upon infection with a related virus due to non-neutralizing antibodies is called:

1. Antigenic shift
2. Antibody-dependent enhancement
3. Immune evasion
4. Viral latency

6. With reference to viral oncogenesis, which of the following mechanisms is/are commonly involved?

1. Integration of viral DNA altering host proto-oncogenes or tumour suppressor genes.
2. Expression of viral oncoproteins that interfere with cell-cycle regulation.
3. Direct encoding of antibiotics by the viral genome.

Select the correct answer using the code below:

1. 1 only
2. 1 and 2 only
3. 2 and 3 only
4. 1, 2 and 3

7. In population-level control of viral diseases, which of the following measures directly reduces the effective reproduction number (R_e)?

1. Widespread use of effective vaccines.
2. Physical distancing and reduction of contact rates.
3. Prompt isolation of infectious individuals.

Select the correct answer using the code below:

1. 1 and 2 only
2. 2 and 3 only
3. 1 and 3 only
4. 1, 2 and 3

8. In the laboratory, which of the following findings most strongly suggests a chronic productive viral infection rather than a latent one?

1. Viral genome detectable but no infectious particles produced.
2. Periodic detection of high titres of infectious virions over long duration.
3. Absence of viral antigens despite strong antibody response.
4. Presence of only proviral DNA integrated into host genome without virion release.

9. Which one of the following is the most appropriate reason why live attenuated viral vaccines are generally contraindicated in pregnancy?

1. They never induce long-lasting immunity in pregnant women.
2. They may replicate and theoretically infect the fetus.
3. They always cause severe disease in pregnant women.
4. They are incapable of eliciting any T-cell response during pregnancy.

10. A virus that is primarily transmitted via the faeco-oral route is most likely to have which of the following characteristics?

1. High stability in acidic pH and in the environment.
2. Absolute dependence on arthropod vectors.
3. Requirement of a lipid envelope for transmission.
4. Exclusive replication inside arthropod gut cells.