Virology

Question 1

Contains either RNA or DNA as genetic material (never both).

Answer 1

Virion

Question 2

viruses are too small to be seen with a light microscope so it’s observed only under an

Answer 2

electron microscope

Question 3

Protein coat protecting the viral genome.

Answer 3

Capsid

Question 4

Combination of genome + capsid

Answer 4

Nucleocapsid

Question 5

Enveloped vs. Naked Viruses:

Answer 5

• Enveloped: Have a lipid membrane derived from the host cell.
• Naked: Lack an envelope, making them more resistant to environmental stress.

Question 6

Glycoprotein spikes on viral envelopes that aid in host recognition.

Answer 6

Peplomers

Question 7

virus morphology

Answer 7

• Helical
• Icosahedral
• Complex

Question 8

Family names end in (suffix)

Answer 8

-viridae

Question 9

Genus names end in

Answer 9

-virus

Question 10

Orders group virus families with shared traits. The only officially recognized order is

Answer 10

Mononegavirales

Question 11

Mononegavirales encompasses what famili

Answer 11

Filoviridae, Paramyxoviridae, and Rhabdoviridae families

Question 12

viruses require a host to replicate meaning they are

Answer 12

obligate intracellular parasites

Question 13

the replication cycle consists of the ff steps

Answer 13

• attachment or adsorption
• penetration or virus entry
• uncoating
• macromolecular synthesis
• viral assembly

Question 14

• virus recognizes and binds to a suitable host cell
• capsid proteins bind to specific host cell receptors
• determines viral tropism

Answer 14

attachment/adsorption

Question 15

• enveloped virus fuse with the host cell membrane
• naked viruses enter via endocytosis

Answer 15

penetration/virus entry

Question 16

• capsid is removed, releasing viral genome into the host cell

Answer 16

uncoating

Question 17

• viral genome directs the host cell to produce viral nucleic acids and proteins
• uses host ribosomes and enzymes

Answer 17

macromolecular synthesis

Question 18

• structural proteins, viral genome and enzymes are assembled into new virus particles
• enveloped viruses acquire their envelope during budding from the host cell membrane

Answer 18

Viral Assembly

Question 19

Cause cell lysis, releasing new virions.

Answer 19

Lytic viruses

Question 20

Bud off from the cytoplasmic membrane, keeping part of the host cell membrane as an envelope

Answer 20

Enveloped viruses

Question 22

What are the three main types of viral infections?

Answer 22

1. Acute viral infection – Symptoms are evident.
   
   2. Latent infection – No symptoms, virus persists in a lysogenic state.
   3. Chronic (persistent) infection – Low levels of virus are present, symptoms vary.

Question 23

When should a specimen be collected for viral diagnosis?

Answer 23

As early as possible after symptom onset.

Question 24

Why should swab specimens be free from chemicals?

Answer 24

To prevent toxicity to cultured cells.

Question 25

What are throat swabs used for?

Answer 25

Recovery of enteroviruses, adenoviruses, and HSV.

Question 26

What are nasopharyngeal swabs or aspirates used for?

Answer 26

Detection of RSV, influenza, and parainfluenza viruses.

Question 27

What are bronchial and bronchoalveolar washes used for?

Answer 27

Lower respiratory tract infections, especially influenza and adenoviruses.

Question 28

What viruses are detected using rectal swabs and stool samples?

Answer 28

• Rotavirus • Enteric adenoviruses (serotypes 40 & 41) • Enteroviruses (stool sample preferred)

Question 29

What viruses can be detected in rectal swabs?

Answer 29

Enteroviruses in suspected enteroviral disease

Question 30

What viruses can be detected in urine samples?

Answer 30

• CMV • Mumps virus • Rubella virus • Measles virus • Polyomaviruses • Adenoviruses

Question 31

How is virus recovery done from urine samples?

Answer 31

1. Centrifugation or filtration 2. Neutralize pH with a 7.5% sodium bicarbonate solution

Question 32

What viruses can be detected in blood samples?

Answer 32

• CMV • HSV • VZV • Enteroviruses • Adenoviruses

Question 33

What anticoagulants are used for viral blood testing?

Answer 33

• CMV: Heparin, citrate, or EDTA • Other viruses: Citrated blood • Nucleic acid testing: EDTA

Question 34

What viruses are detected in tissue samples?

Answer 34

• CMV • Influenza virus • Adenovirus • Sin Nombre virus • HSV

Question 35

What is the preferred form of tissue for nucleic acid assays?

Answer 35

Fresh tissue (formalin-fixed tissue can be used after deparaffinization)

Question 36

What viruses are detected in genital specimens?

Answer 36

HSV and HPV

Question 37

What type of specimen is collected for antibody testing?

Answer 37

Serum

Question 38

Collected ASAP after symptoms appear

Answer 38

Acute specimens

Question 39

Collected 2-3 weeks after the acute specimen

Answer 39

Convalescent specimens

Question 40

What is the purpose of a viral transport medium?

Answer 40

To preserve viral stability in specimens.

Question 41

What does a viral transport medium contain?

Answer 41

• Buffered isotonic solution • Protein (albumin, gelatin, or serum)

Question 42

What temperature should specimens be stored at?

Answer 42

• 4°C: Short-term storage • -70°C: If delay >4 days • Never store at -20°C

Question 43

What are the main diagnostic methods for viruses?

Answer 43

1. Direct virus detection in clinical specimens 2. Nucleic acid-based detection 3. Virus isolation in cell cultures (gold standard) 4. Serologic assays for antibody detection