Virus Quiz : Test your knowledge

1. Which of the following is the most appropriate description of a “viral reservoir host”?

1. A host in which the virus always causes fatal disease.
2. A host species in which the virus is maintained in nature, often with minimal disease.
3. A host used only for vaccine production in laboratories.
4. A host that is infected only once and then eliminates the virus permanently from the ecosystem.

2. With reference to “viral envelope glycoproteins”, which of the following is/are generally true?

1. They are often key determinants of cell receptor binding.
2. They are major targets of neutralizing antibodies.
3. They are composed entirely of host cell DNA.

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. The term “time-varying R_t” (effective reproduction number at time t) is useful in epidemics because it:

1. Stays constant regardless of interventions.
2. Reflects changes in transmission as behavior, immunity, or control measures evolve.
3. Can be calculated only after the epidemic has ended.
4. Is always higher than the basic reproduction number R₀.

4. In the context of viral vaccines, “cold chain” mainly refers to:

1. Use of antiviral drugs stored at low temperatures.
2. System of storage and transport that maintains vaccines within recommended temperature ranges.
3. Exclusive use of frozen syringes for administration.
4. Requirement that all vaccines must be stored below 0°C.

5. “Host range restriction” of a virus is largely determined by:

1. Availability of suitable receptors and intracellular replication machinery in the host species.
2. Ambient humidity alone.
3. Color of the host’s skin or fur.
4. Presence of bacterial co-infections only.

6. With reference to “post-viral fatigue” observed after some acute viral illnesses, which of the following is/are correct?

1. It may persist for weeks to months after clearance of active infection.
2. Its exact mechanisms are not fully understood and may involve immune and metabolic factors.
3. It indicates that the virus is always replicating at high levels in blood.

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. In outbreak analytics, a “serial interval” for a viral infection is defined as the time between:

1. Initial exposure and first symptom in the same person.
2. Symptom onset in a primary case and symptom onset in a secondary case infected by that primary case.
3. Detection of virus in laboratory and publication of results.
4. Start and end of vaccination campaign.

8. Which of the following surveillance strategies is best suited to detect early community circulation of a respiratory virus?

1. Testing only hospitalized intensive care unit patients.
2. Wastewater (sewage) surveillance for viral RNA along with sentinel outpatient testing.
3. Screening only international travelers at airports and nowhere else.
4. Relying solely on death registration data.

9. For a viral disease controlled mainly by childhood immunization, which of the following most directly threatens long-term control?

1. Maintaining high routine coverage in infants.
2. Consistent cold-chain maintenance.
3. Persistent “immunity gaps” in certain geographic or socio-economic groups.
4. Regular updating of vaccination schedules based on evidence.

10. In many zoonotic viral infections, “dead-end host” (spillover host) refers to a host that:

1. Cannot be infected by the virus under any circumstances.
2. Gets infected but does not contribute significantly to onward transmission.
3. Always becomes the new primary reservoir.
4. Clears the virus instantly without any immune response.