250+ TOP MCQs on Transmission and Evolution of Viruses and Answers

Virology Multiple Choice Questions & Answers focuses on “Transmission and Evolution of Viruses”.

1. Which of the following is not a horizontal transmission route?
a) Respiratory
b) Placental
c) Fecal
d) Sexual

Answer: b
Clarification: The placental route is the vertical transmission route where transmission occurs from mother to fetus. Whereas respiratory, fecal, sexual, etc. are the horizontal transmission route.

2. Which of the following virus is transmitted through the respiratory route?
a) HIV
b) HBV
c) HPV
d) Rhinovirus

Answer: d
Clarification: Rhinovirus is the virus that is transmitted through the respiratory route. Whereas Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), and Papillomavirus (HPV) are transmitted through sexual routes.

3. Which of the following virus is transmitted via urine?
a) Influenza virus
b) Poliovirus
c) Lassa fever virus
d) Arbovirus

Answer: c
Clarification: Lassa fever virus (an African arenavirus) is transmitted via urine. This virus infects wild mice. Sin Nombre, a North American bunyavirus, is also transmitted via urine. Both viruses cause rare human fatalities.

4. Which of the following phylum acts as a vector for virus transmission?
a) Arthropods
b) Mollusca
c) Porifera
d) Cnidaria

Answer: a
Clarification: Arthropods found in tropical parts, act as a vector for virus transmission. The arthropod feeds on the human body by piercing the skin with their mouthparts. During their next meal, they inject saliva as an anticoagulant, and in doing so introduces the virus that was picked up from the previous meal.

5. The viruses spread by arthropods are known as ____________
a) Rhinovirus
b) Arbovirus
c) Influenza virus
d) HIV

Answer: b
Clarification: The viruses spread by arthropods (arthropod-borne virus) are known as arbovirus and the disease spread by arbovirus is known as arboviral disease. The infection usually occurs during warm weather months when mosquitoes and ticks are active.

6. Which of the following is an example of a vertically transmitted virus?
a) Arbovirus
b) Rhinovirus
c) Poliovirus
d) Rubella virus

Answer: d
Clarification: The rubella virus is a classic example of a vertically transmitted virus. It spreads by the respiratory route. The risks of malformations arising from rubella virus infection are high in the early stages of pregnancy and it becomes almost no risk by the fifth month or later stages.

7. Which of the following virus undergoes zoonotic transmission?
a) Rhinovirus
b) HIV
c) HBV
d) Rhabdovirus

Answer: d
Clarification: Rhabdovirus transmits through the zoonotic transmission. It causes rabies which is a well-known zoonosis. It is transmitted directly by the bite of an infected vertebra and it infects many different species.

8. Which of the following virus belongs to the poxvirus family?
a) HIV
b) Myxoma
c) Measles
d) Influenza

Answer: b
Clarification: Myxoma virus belongs to the poxvirus family. The natural host of myxoma virus is the South American rabbit in which it causes minor skin outgrowths. It also infects the European rabbit causing myxomatis and is spread by arthropod vectors.

9. Influenza A virus was discovered in ______________
a) 1933
b) 1937
c) 1999
d) 1958

Answer: a
Clarification: Influenza A virus was discovered in 1933 and since then they have been isolated every year from humans around the world. It causes worldwide epidemics, that is, pandemics and each new isolate are tested serologically with antibody to all other influenza strains.

10. Influenza B undergoes more drift than influenza A viruses.
a) True
b) False

Answer: b
Clarification: Influenza B virus undergo less drift than influenza A virus. The antigenic drift happens on a global scale and it results in epidemics and is caused under the positive selection pressure of neutralizing antibodies.

11. The mucus prevents viral attachment on cells.
a) True
b) False

Answer: a
Clarification: The mucus serves as a physical barrier that prevents the attachment of the virus to its receptor on the surface of the cells. The virus cannot identify the receptor on the cell surface and thus, cannot attach to the cells.