Veenu

Question 1

What is the primary method for identifying viral infections based on patient symptoms?

Answer 1

Patient history and symptoms, exclusion of other types of infection, recent travel history

This method is often inconclusive and requires laboratory tests for confirmation.

Question 2

What percentage of infectious diseases seen by a physician are viral?

Answer 2

About 60%

This statistic highlights the prevalence of viral infections in clinical settings.

Question 3

What are the three main categories of diagnostic methods in virology?

Answer 3

1. Direct Examination
2. Indirect Examination
3. Serology

Each category has distinct techniques for identifying viral infections.

Question 4

What specimens can be used for direct detection of viruses?

Answer 4

• Nasopharyngeal aspirates
• Faeces
• Vesicle Fluid
• Skin scrapings
• Spinal fluid

These specimens are crucial for identifying specific viruses.

Question 5

What is the advantage of using Electron Microscopy in viral diagnostics?

Answer 5

Ability to visualize the virus and process specimens quickly

Electron Microscopy can provide rapid results but requires a minimum number of virus particles.

Question 6

What is the main use of ELISA in virology?

Answer 6

Detection of antibodies and antigens in blood

ELISA is known for being reliable, sensitive, and easy to perform.

Question 7

What is a disadvantage of using Light Microscopy for viral diagnosis?

Answer 7

Not sensitive or specific, but useful as an adjunct in diagnosis

Light Microscopy can reveal histological changes but may miss certain infections.

Question 8

What is the purpose of PCR in viral diagnostics?

Answer 8

Amplification of specific DNA sequences for virus detection, genotyping, and quantification

PCR can detect very low levels of viral genomes, enhancing early diagnosis.

Question 9

Fill in the blank: The __________ test is used to identify DNA in viral diagnostics.

Answer 9

Southern blot

Southern blotting separates DNA fragments and uses hybridization for detection.

Question 10

True or False: Northern blot uses RNA while Southern blot uses DNA.

Answer 10

True

This distinction is critical for understanding molecular diagnostic techniques.

Question 11

What is the Cytopathic Effect (CPE) in viral diagnostics?

Answer 11

Observable morphological changes in cells due to viral replication

CPE can be specific or non-specific depending on the virus.

Question 12

What are some limitations of serological analysis?

Answer 12

• Clinical symptoms may precede antibody appearance
• Reduced immune response in immunocompromised patients

These limitations can affect the accuracy of viral infection diagnosis.

Question 13

What is the role of the Virus Neutralization Test in serology?

Answer 13

Incubating virus with patient serum to detect unneutralized virus via reactions

This test is specific but can be slow.

Question 14

What is the significance of Hemagglutination in viral diagnostics?

Answer 14

Some viruses have proteins that cause erythrocytes to clump together

Hemagglutination assays can indicate viral presence but are sensitive to specimen conditions.

Question 15

Differentiate between direct and indirect methods of viral diagnosis with examples.

Answer 15

Direct methods: * Electron Microscopy, * PCR
Indirect methods: * Cell culture, * Serology

Direct methods detect the virus directly, while indirect methods infer viral presence through host response.

Question 16

What types of cell cultures are used in viral diagnostics?

Answer 16

• Primary cell culture
• Continuous cell cultures

Primary cultures are derived from normal cells and have limited lifespan, while continuous cultures come from cancer cells and are easier to handle.