Viral Families and Disease

Question 1

What are the signs of viral propagation?

Answer 1

Presence of intracellular double-stranded RNA > interferon
Presentation of surface antigen > Tc and NK cells
Formation of intracellular inclusion bodies

Question 2

This is observation of virus-induced cytopathologic effects on cells, e.g.: inclusion bodies, cell lysis, vacuolation, synctia

Answer 2

cytology

Question 3

For the following structures, name what virus it confirms:

Cowdry type A nuclear inclusion bodies

Answer 3

HSV, VZV

Question 4

For the following structures, name what virus it confirms: negri bodies

Answer 4

rabies

Question 5

For the following structures, name what virus it confirms: Nuclear owl’s eye inclusions

Answer 5

CMV

Question 6

For the following structures, name what virus it confirms: cell lysis

Answer 6

enteroviruses

Question 7

For the following structures, name what virus it confirms: vacuolation, syncytia

Answer 7

paramyxoviruses, HSV, VZV, HIV

Question 8

What is the gold standard in diagnosing a virus

Answer 8

a culture or PCR

Question 9

this is the presence of rubella infecting a cell which prevents growth of picornavirus on the same cells

Answer 9

heterologous interference

Question 10

What are hemagglutinins?

Answer 10

receptors that cause erthrocytes to bind to the infected cell surfaces

Question 11

A plaque is a viral “___”

Answer 11

colony

Question 12

This is a 4-fold increase in titer between acute and convalescent phases (3 weeks apart) and proves identity of the disease agent

Answer 12

virus-specific seroconversion

Question 13

What is titer?

Answer 13

how far a serum sample can be diluted and still test positive

ex: 1/64 is highest dilution, then titer = 64

Question 14

Antibody development occurs __-__ days after infection starts

Answer 14

7-10

Question 15

Low pH of inflammatory exudates
Enzymes
Mucous
Virocidins

These are all what type of host defense mechanisms?

Answer 15

Non-specific (innate) - Humoral factors

Question 16

Nucleases
Proteases
Interferon

These are all what type of host defense mechanisms?

Answer 16

Non-specific (innate) - cellular factors

Question 17

antibody
activated lymphocytes
cell-mediated immune system

These are all what type of defense mechanisms?

Answer 17

specific

Question 18

Animal virus cytolysis tends to be a result from a ____ reaction

Answer 18

hypersensitivity reaction

Question 19

This occurs when a bacteriophage fills up with cells, causing them to burst

Answer 19

cell lysis

Question 20

This type of hypersensitivity reaction involves the IgE on mast cells which reacts with viral components and triggers a local anaphylaxis

Answer 20

Type I

Question 21

This type of hypersensitivity reaction involves IgG or IgM. C’ and viral components are adsorbed or embedded in the cell membrane to induce cytolysis

Answer 21

Type II

Question 22

This type of hypersensitivity reaction involves IgG or IgM antibodies and forms complexes with viral antigen and complement, generating neutrophil chemotactic factors, with resultant local tissue inflammation and destruction

Answer 22

Type III

ex: vasculitis

Question 23

In this type of hypersensitivity reaction, antibody is NOT involved. Sensitized T-lymphocytes react directly with viral antigen, usually that antigen expressed on the surface of an infected cell, producing inflammation and cytolysis. This is probably the second most common allergic reaction to viruses

Answer 23

Type IV

Question 24

In regard to cytotoxicity of preformed viral parts, measles virus produces rapid _____

Answer 24

polykarycytosis (fusion of chromosomes)

Question 25

Herpesvirus components produce ____ by cell fusion. This leads to a positive ____ test

Answer 25

syncytia; Tzanck

Question 26

Penton of ____ causes cell rounding and detachment from glass

Answer 26

adenovirus

Question 27

A double-stranded RNA from ____ causes rapid death, without the production of infectious virus

Answer 27

enterovirus

Question 28

Capsid fiber antigen (adenovirus) inhibits ___, ___ and ___ synthesis

Answer 28

DNA, RNA, protein

Question 29

Large quantities of some ___ viruses, such as influenza and poxvirus, cause rapid effects in some animals

Answer 29

killed

Question 30

____ process involves the integration of viral nucleic acid into the host chromosome

Answer 30

transformation

Question 31

For each type of structural alteration due to viral infection, give an example:
cytoplasmic changes
nuclear changes
membrane changes

Answer 31

cytoplasmic changes: inclusion bodies, vacuoles
nuclear changes: pyknosis, inclusion bodies
membrane changes: membrane projections (hemagglutinins)