250+ TOP MCQs on Diagnosis of Viral Infections and Answers

Virology Multiple Choice Questions & Answers (MCQs) focuses on “Diagnosis of Viral Infections”.

1. Which of the following is the first step for the detection of viral infections?
a) Storage
b) Collection
c) Transportation
d) Testing

Answer: b
Clarification: The first step for the detection of viral infection is the collection of samples or specimens which are thought to be virally infected. These samples include blood, urine, CSF, semen, etc.

2. The blood is stored between the temperature range of ____________ °C.
a) 6 – 10
b) 1 – 2
c) 2 – 6
d) 10 – 12

Answer: c
Clarification: The blood is stored between the temperature range of 2 – 6 °C. The addition of anticoagulants such as heparin, sodium fluoride, etc. is important along with preservatives such as sodium azide.

3. Which of the following microscope was used to first identify human rotavirus?
a) Light microscope
b) Phase-contrast microscope
c) Dissection microscope
d) Electron microscope

Answer: d
Clarification: Electron microscope first identified the human rotaviruses. Caliciviruses, astroviruses, hepatitis A, and other viruses such as adenoviruses and coronaviruses were first identified using an electron microscope.

4. Which of the following is added to improve the visualization of virions in immunoelectron microscopy?
a) Silver
b) Platinum
c) Gold
d) Bronze

Answer: c
Clarification: The antibody is labeled with gold to improve the visualization of virions in immunoelectron microscopy. A specific antibody is added to the specimen before depositing the virus-antibody complexes by centrifugation and negative staining. The virions are observed to be aggregated.

5. Which of the following method is used for the detection of antigen?
a) EIA
b) PCR
c) Dot-blot hybridization
d) Boiling lysis

Answer: a
Clarification: Enzyme Immunoassay (EIA) is the method used for the detection of antigen. It is also called as Enzyme-Linked Immuno-Sorbent Assay (ELISA). It can be designed in different formats to detect antigen or antibody.

6. In which of the following method the antibody is labeled with a fluorophore?
a) TR-FIA
b) PCR
c) Dot-blot hybridization
d) Alkaline lysis

Answer: a
Clarification: Time-resolved fluorescence immunoassay (TR-FIA) is the method in which the indicator antibody is labeled with a fluorophore. It is a non-isotopic immunoassay and is a sensitive method for viral detection but it requires costly equipment.

7. Which of the following method is used for the detection of viral DNA?
a) Western blotting
b) Northern blotting
c) Eastern blotting
d) Southern blotting

Answer: d
Clarification: Southern blotting is used for the detection of viral DNA whereas northern blotting is used for RNA detection and western blotting is used for protein detection.

8. In which of the following method there are chances of DNA contamination?
a) PCR
b) ELISA
c) EM
d) IgM serology

Answer: a
Clarification: In polymerase chain reaction (PCR), there are higher risks of contamination of DNA and PCR may also result in unspecific amplification and this might lead to wrong results. However, PCR is a very rapid and sensitive technique.

9. In which of the following method the antibody is labeled with HRP?
a) PCR
b) Immunoperoxidase
c) In situ hybridization
d) Direct EIA

Answer: b
Clarification: Immunoperoxidase staining is the method in which the antibody is labeled with horseradish peroxidase enzyme (HRP enzyme). The main advantage of this method is that only an ordinary light microscope is needed.

10. CSF is a red color fluid.
a) True
b) False

Answer: a
Clarification: Cerebrospinal fluid is a colorless fluid present in the brain. It is an important fluid for the protection of the brain and spinal cord from trauma and supplies nutrients to the brain.

11. Sandwich ELISA requires two antibodies.
a) True
b) False

Answer: a
Clarification: Sandwich ELISA requires two antibodies, where each antibody is specific for a different, non-overlapping part of the antigen molecule. The first antibody is known as capture antibody and the second antibody is known as the detection antibody.