Virology

Question 1

What is the basic structure of a virus and what how can its activity be described?

Answer 1

Basically includes a protein coat (capsid) that is around a nucleic acid core. May or may not be enveloped (viri without them are called naked). Outer surface contains molecules specific to infect target cells. Can be active or inactive (in opposition to being described as ‘alive’ or ‘dead’)

Question 2

What is the construction of the capsid?

Answer 2

Capsid made of capsomeres of various geometric conformations; may contain proteins and enzymes that abet infection

Question 3

What types of nucleic acid can exit in viruses?

Answer 3

Single or double stranded DNA or RNA

Question 4

What TLRs are particularly sensitive to viral RNA?

Answer 4

TLR 3, 7, 8, and 9

Question 5

What is meant by describing viral RNA as positive or negative?

Answer 5

If a strand can immediately be translated on host invasion, it is considered positive; if not, it is negative

Question 6

What are the five stages in the viral life cycle?

Answer 6

1) Adsorption–capsid spikes bind to glycoproteins on the cell surface
2) Penetration–virus is engulfed, capsid and envelope degrade
3) Synthesis–viral material replicated
4) assembly–mature viral components put together
5) Release–lysis occurs and viral particles are released

Question 7

How might cells that are actively infected be noticed on microscopic examination?

Answer 7

Cells may show inclusions for viral production, can have changes in size and shape, and cells may fuse into syncytia

Question 8

Classify the following family and identify some diseases in it:
Poxviridae

Answer 8

DNA virus; Variola/vaccinia (smallpox and cowpox)

Question 9

Classify the following family and identify some diseases in it:
Herpesviridae

Answer 9

DNA virus; Herpes simplex, varicella, CMV, EBV

Question 10

Classify the following family and identify some diseases in it:
Adenoviridae

Answer 10

DNA virus; human adenovirus

Question 11

Classify the following family and identify some diseases in it:
Papovaviridae

Answer 11

DNA virus; HPV family

Question 12

Classify the following family and identify some diseases in it:
Hepadnaviridae

Answer 12

DNA virus; Hepatitis B

Question 13

Classify the following family and identify some diseases in it:
Parvoviridae

Answer 13

DNA virus; parvovirus; erythema infectiosum

Question 14

Classify the following family and identify some diseases in it:
Picornaviridae

Answer 14

RNA virus; polio, coxackie virus, Hepatitis A, Rhinovirus

Question 15

Classify the following family and identify some diseases in it:
Caliciviridae

Answer 15

RNA virus; Norwalk virus

Question 16

Classify the following family and identify some diseases in it:
Togaviridae

Answer 16

RNA virus; Eastern, Western, St. Louis encephalitis; Rubella

Question 17

Classify the following family and identify some diseases in it:
Flaviviridae

Answer 17

RNA virus; Dengue fever, West Nile, Yellow fever

Question 18

Classify the following family and identify some diseases in it:
Coronaviridae

Answer 18

RNA virus; bronchitis, enteritis, SARS

Question 19

Classify the following family and identify some diseases in it:
Filoviridae

Answer 19

RNA virus; ebola

Question 20

Classify the following family and identify some diseases in it:
Orthomyxoviridae

Answer 20

RNA virus; influenza

Question 21

Classify the following family and identify some diseases in it:
Paramyxoviridae

Answer 21

RNA virus; parainfluenza and mumps

Question 22

Classify the following family and identify some diseases in it:
Rhabdoviridae

Answer 22

RNA Virus; Rabies

Question 23

Classify the following family and identify some diseases in it:
Bunyaviridae

Answer 23

RNA virus; California encephalitis, Hantavirus

Question 24

Classify the following family and identify some diseases in it:
Reoviridae

Answer 24

RNA virus; Colorado tick fever, rotavirus, measles, RSV

Question 25

Classify the following family and identify some diseases in it:
Retroviridae

Answer 25

RNA virus; HIV, T-cell leukemia

Question 26

Classify the following family and identify some diseases in it:
Arenaviridae

Answer 26

RNA virus; Lassa virus

Question 27

What are some of the innate mechanisms that the host organism uses to ward viral infection?

Answer 27

Interferons (alpha and beta), defensins, APOBEC3G (antiretroviral), NK cells, TLR

Question 28

What are some of the adaptive mechanisms that the host organism uses to ward viral infection?

Answer 28

Antibodies, CD8+ mediated destruction of infected cell, Th1 mediated macrophage activation

Question 29

How does post-influenza toxic shock syndrome occur?

Answer 29

Respiratory infections introduce opportunities for pathogenic bacteria to invade respiratory epithelium. The most common etiologies for these include H. influenzae, S. pneumoniae, and S. aureus

Question 30

What are the main proteins involved with the influenza viral capsid?

Answer 30

Hemagglutinin is the major component that recognizes sialic acid on the host cell, but must be activated by a protease to mature
Neuraminidase is not relevant to infection, but required for release from the cell (target of tamiflu)