Virus Quiz : Test your knowledge

1. Which of the following best explains why viruses are considered ‘acellular’ entities?

1. They are too small to be seen under a microscope.
2. They lack typical cellular organelles and do not carry out independent metabolism.
3. They always live inside red blood cells.
4. They cannot survive outside the host under any conditions.

2. With reference to DNA viruses, which of the following statements is/are correct?

1. Many DNA viruses replicate in the host cell nucleus.
2. DNA viruses generally have lower mutation rates than RNA viruses.
3. All DNA viruses necessarily possess a segmented 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

3. Which of the following best describes “viral load”?

1. Total amount of antibodies present in the host against a virus.
2. Concentration of virus particles in a given volume of a body fluid.
3. Weight of the viral capsid measured in laboratory conditions.
4. Number of viral proteins produced inside a single cell.

4. Consider the following statements about viral envelopes:

1. They typically contain host cell lipids and viral glycoproteins.
2. They play a role in attachment and entry into host cells.
3. They always make the virus more resistant to environmental conditions.

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 primary rationale for using combination antiviral therapy (e.g., in HIV infection) is to:

1. Increase the side effects so that the patient adheres better to treatment.
2. Target multiple stages of the viral life cycle and delay resistance.
3. Ensure that the virus becomes more visible to the immune system.
4. Convert the virus from RNA to DNA and back repeatedly.

6. With reference to “antigenic shift” in influenza viruses, which of the following is correct?

1. It is caused by point mutations in the viral genome over several seasons.
2. It occurs only in non-segmented RNA viruses.
3. It may arise from reassortment of gene segments between different viral strains.
4. It always leads to immediate extinction of the virus in nature.

7. In a population, which of the following would directly increase the basic reproduction number (R₀) of a virus?

1. Increase in the average number of contacts per person per unit time.
2. Increase in the probability of transmission per contact.
3. Increase in the duration of infectiousness of an infected individual.

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. With reference to laboratory diagnosis of viral infections, which of the following methods detects viral genetic material directly?

1. Enzyme-linked immunosorbent assay (ELISA)
2. Polymerase chain reaction (PCR)
3. Haemagglutination inhibition test
4. Viral culture in cell lines only

9. Which of the following is the most appropriate explanation for “window period” in viral infections such as HIV?

1. Time between exposure and virus entering the bloodstream.
2. Time between infection and the appearance of detectable antibodies, during which tests may be falsely negative.
3. Time between vaccination and onset of immunity.
4. Time during which the virus is present only in vector species.

10. A virus that causes a brief symptomatic illness followed by complete elimination from the body without persistence is best described as causing:

1. Chronic productive infection
2. Latent infection with reactivation
3. Acute self-limited infection
4. Slow progressive infection