Lecture 3: pathogenesis

Question 1

the manner of development of a disease

Answer 1

pathogenesis

Question 2

ability of the virus to cause disease

Answer 2

pathogenicity

Question 3

relative measure of the pathogenicity of the infecting virus

Answer 3

virulence

Question 4

well characterized virus

Answer 4

strain

Question 5

refers to the virus recovered from a specific host or location

Answer 5

isolate

Question 6

sub-group of viruses that share antigens recognized by antibodies of the immune system

Answer 6

serotype

Question 7

the outcome of viral exposure/infection is influenced by

Answer 7

-method of transmission

-number of infecting particles (dose)

-virulence of infecting particles (genetics)

-speed of viral replication and spread

-degree of cellular damage

-effectiveness of host defenses

Question 8

ways that viruses can effect host animal

Answer 8

induction of chronic progressive disease

induction of cancer

acute or subclinical disease

direct damages to cells due to cell death/apoptosis

disruption of normal cell functions

immune responses to viral virus infected cells

Question 9

all viruses are _______ ___________ pathogens

Answer 9

obligate intracellular

Question 10

steps in virus infection

Answer 10

virus binds to receptors on cells

nature, number and distribution of host cell receptors determine the host range and the tissue tropism of the virus

bound virion is taken into cell through endocytosis or fusion to the plasma membrane

capsid is dismantled so that its nucleic acid is released into the cytoplasm by a process called uncoating

once the viral genome is uncoated, replication begins

Question 11

outcome of the virus-host encounter is the product of

Answer 11

virulence of the infecting virus AND
susceptibility of the host

Question 12

host factors influencing pathogenesis

Answer 12

genetic
age
hormonal influence
healthy living conditions
concurrent or mixed infections
exposure to vecotrs
immunity

Question 13

host factors influencing pathogenesis: genetic

Answer 13

species, breed, organ/tissue, susceptibility, intracellular hospitality

Question 14

host factors influencing pathogenesis: age

Answer 14

neonate vz. geriatric

young–dont have a highly developed immunity

Question 15

host factors influencing pathogenesis: hormonal influence

Answer 15

pregnancy (body is under more stress than normal)

Question 16

host factors influencing pathogenesis: healthy living conditions

Answer 16

temperature
crowding
nutrition
air flow

Question 19

host factors influencing pathogenesis: immunity

Answer 19

innate
passive
acquired

Question 20

some viruses have evolved to preferentially target certain cell types tissues or host

Answer 20

tropism

Question 21

example: HIV attacks macrophages instead of neurons

Answer 21

cellular tropism

Question 22

example: influenza virus normally infects lung tissue but not brain tissue

Answer 22

tissue tropism

Question 23

neurotropic

Answer 23

direct inoculation

replicate at primary site

shed in secretions

systemic disease usually occurs

rabies moved toward CNS

Question 23

example: myxoma virus infects rabbits but not humans

Answer 23

host tropism

Question 24

tropic areas in the body

Answer 24

neuro
epithelial
GI
respiratory
lymphoid system
immune system cells

Question 25

infection limited to the site of entry of the virus

examples: skin, respiratory, alimentary tract

Answer 25

localized infection

Question 26

infection spread to various organ systems depending on viral tropism

Answer 26

systemic infection

Question 27

congenital infections

Answer 27

viral infections during pregnancy (in utero, during birth, congenital defect, fetal death)

usually transferred to the fetus during the viremic phase of the dam

Question 28

reproductive failure, abortions, and teratogenic defects may result due to congenital infections

what are some influences

Answer 28

the stage of gestation at the time of infection

transmission of infection to the fetus

ability to cause fetal damage

Question 29

a short incubation period with clinical recovery

virus stays in host animal for long periods with or without clinical disease

Answer 29

persistent infection

Question 30

persistent virus infection have:

list characteristics

Answer 30

long incubation periods (years)

a protracted clinical course

usually result in serious disease and death

Question 31

a persistent infection in which the latent virus is activated intermittently, resulting in a rapid viral replication and recurrent manifestation of disease

Answer 31

latent infection

Question 32

_____________ remain latent and can be reactivated by stress or corticosteroid treatment

**never clears infection

Answer 32

herpes

Question 33

why are inapparent infection epidemiologically important

Answer 33

serve as an unrecognized source for the spread of viruses (COVID)

Question 34

inapparent infections are associated with:
(list 4)

Answer 34

infection of a reservoir species/host

low infectious dose

infection with viruses of low virulence

host resistance

Question 35

example of DNA tumor viruses

Answer 35

papovavirus (warts)
herpes
adenovirus

Question 36

example of RNA tumor viruses

Answer 36

retrovirueses

Question 37

affecting the entire body, rather than a single organ or body part

Answer 37

systemic disease