Virus Quiz : Test your knowledge

1. In a viral epidemic, “generation time” is best described as the time interval between:

1. Initial exposure and seroconversion in the same person.
2. Infection in a primary case and infection in a secondary case caused by that primary case.
3. Symptom onset and recovery in the same individual.
4. Introduction of the virus and declaration of an epidemic by authorities.

2. With reference to “viral RNA detection by RT-PCR”, which of the following is/are correct?

1. A positive RT-PCR indicates presence of viral RNA in the sample tested.
2. It does not always prove the presence of viable, infectious virus.
3. It can never detect infection in the pre-symptomatic phase.

Select the correct answer using the code below:

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

3. “Non-structural proteins” of viruses are typically:

1. Major components of the virion capsid.
2. Proteins expressed in infected cells that assist replication or regulation but are not packaged in large amounts into virions.
3. Host cell enzymes unrelated to infection.
4. Always viral surface glycoproteins.

4. In many viral infections, “mucosal immunity” is important because:

1. Most viruses enter only via parenteral routes.
2. Secretory IgA and local immune cells at mucosal surfaces can neutralize virus at portals of entry.
3. Mucosal surfaces do not contain any lymphoid tissue.
4. It replaces the need for systemic immunity entirely.

5. “Zoonotic amplification host” in viral ecology refers to an animal species that:

1. Cannot sustain viral replication.
2. Allows high-level viral replication and increases transmission to vectors or other hosts.
3. Is used only in laboratory experiments.
4. Instantly clears the virus on exposure.

6. With reference to “viral cytopathic effect (CPE)” in cell culture, which of the following is/are correct?

1. CPE includes morphological changes such as cell rounding, syncytia, or lysis.
2. Different viruses can produce characteristic patterns of CPE useful for identification.
3. CPE is never associated with viral replication.

Select the correct answer using the code below:

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

7. “Rings of immunity” around detected viral cases are created in the community primarily by:

1. Quarantine of contacts alone.
2. Ring vaccination plus targeted public health measures around cases and their contacts.
3. Mass chemoprophylaxis with antibiotics.
4. Closing all international borders permanently.

8. In a “test–trace–isolate” strategy for viral control, which step directly reduces the infectious period in the community?

1. Testing alone.
2. Isolation of detected cases away from susceptible individuals.
3. Tracing without any further action.
4. Only sequencing viral genomes.

9. “Pathogen spillback” in viral ecology denotes:

1. Transmission from animal reservoirs to humans only.
2. Transmission from humans back into animal populations after human amplification.
3. Transmission exclusively via contaminated water.
4. Reversion of attenuated vaccine strains to wild-type in humans.

10. For a chronic blood-borne viral infection, which combined measure set is MOST appropriate to reduce new infections at the population level?

1. Needle–syringe programmes and safe injection practices only.
2. Safe blood transfusion, harm reduction for people who inject drugs, screening of pregnant women, and treatment of infected persons.
3. Improving air ventilation in schools.
4. Vector control with insecticides only.