Virology@RUSVM > Host-Pathogen Interactions > Flashcards

Host-Pathogen Interactions Flashcards

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1
Q

pathogenicity

A

the ability of a virus to cause disease

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2
Q

pathogenesis

A

manner/mechanism of development of a disease

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3
Q

virulence

A

quantitative or relative measure of the degree of pathogenicity. depends on both the host and the virus

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4
Q

lethal dose 50

A

the dose of the virus required to cause death in 50%

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5
Q

infectious dose 50

A

the dose of the virus that will infect 50% of an experimental group of hosts/animals

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6
Q

ID50:LD50 ratio

A

ratio of the dose of a particular strain of virus that causes infection in 50% to the dose that kills 50%

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7
Q

the lower the ID50 and LD50…… the _______virulent

A

more

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8
Q

incubation period

A

from the time infected to the time where you see clinical signs

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9
Q

sequential steps of viral infection (5 steps)

A

entry of virus & primary replication; spread, tropism, & infection of target organs; virus-cell interactions; tissue & organ injury; shedding

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10
Q

skin defenses

A

keratin, low pH, fatty acids, bacterial flora, dryness

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11
Q

mucous membrane defenses

A

IgA, virucidal proteins

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12
Q

GI tract defenses

A

mucous membranes, acidity of stomach, alkalinity of intestine, lipolytic activity of bile, proteolytic activity of pancreatic enzymes, defensins, IgA, macrophages

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13
Q

respiratory tract defenses

A

mucocilliary blanket, alveolar macrophages, NALT, BALT, temperature gradient

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14
Q

disseminated infection

A

infection spreads beyond the primary site of infection

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15
Q

systemic infection

A

if a number of organs or tissues are infected

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16
Q

apical release of virus

A

facilitates virus dispersal

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17
Q

basolateral release

A

provides access to underlying tissue, facilitates systemic release

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18
Q

viremia

A

the presence of a virus in the blood. may be free in the blood or in a cell in the blood

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19
Q

passive viremia

A

direct inoculation of the virus into the blood. bite of arthropod, infected syringe

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20
Q

primary viremia

A

initial entry of virus into the blood after infection (1st time virus in the blood)

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21
Q

secondary viremia

A

virus has replicated in major organs and once more has entered the blood

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22
Q

active viremia

A

viremia following initial virus replication in host. release of virions from the initial site of replication.

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23
Q

virus interaction with macrophages (5 things can happen)

A

1- virions are phagocytosed
2- virions replicate inside macrophage, activate macrophages
3- tissue invasion (trojan horse)
4- phagocytosed and transfered to adjacent cells
5- failure to phagocytose, prolonged viremia

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24
Q

virus spread/interaction with endothelial cells

A

fenestrae (small pores), trafficking lymphocytes or monocytes, transcytosis (vesicular transport), replication in endothelial cells

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25
neurotropic virus
viruses that can infect neural cells
26
neuroinvasive virus
viruses that can ender the CNS
27
neurovirulent virus
viruses that cause disease of nervous tissue
28
Herpes simplex virus (neuroinvasiveness, neurovirulence)
low neuroinvasiveness | high neurovirulence
29
Mumps virus (neuroinvasiveness, neurovirulence)
high neuroinvasiveness | low neurovirulence
30
Rabies virus (neuroinvasiveness, neurovirulence)
high neuroinvasiveness | high neurovirulence
31
neural spread of viruses (transport)
via axons, perineural lymphatics, endoneural space, schwann cells
32
retrograde spread
virus travels opposite direction of nerve impulse flow
33
anterograde spread
travel in the same direction as nerve impulses
34
centripetal movement of virus
towards the CNS/brain
35
centrifugal movement of virus
from the CNS to other body locations
36
spread of viruses to the CNS via...
olfactory routes | blood-brain barrier
37
acute infection
usually intensive shedding over a short period of time
38
persistent infection
shed at lower titers for months to years
39
tropism
the specificity/affinity of a virus for a particular host tissue
40
pantropic virus
can replicate in more than one host organ/tissue
41
what determines viral tropism
receptors on host cells, viral attachment proteins, viral enhancers, cell proteases, temperature, acid lability, transcriptional control of tropism, anatomic barriers, host organ response
42
rash
general term applied to any temporary eruption on the skin
43
vesicles
fluid filled cavities
44
ulcer
raw opening in skin due to sluffing of necrotic tissue
45
nodules
growths
46
warts
benign skin growths (papillomavirus)
47
papules
seen in papular stomatitis in cattle
48
erythema
reddening of the skin (hog cholera)
49
DIC (disseminated intravascular coagulation)
complication arising from viral infection of blood vessels. wide spread activation of the clotting cascade that results in the formulation of blood clots in small vessels in the body.
50
teratogenesis
abnormal development or arrest in development of the embryo or fetus
51
porencephaly
holes in the brain
52
BVDV in cattle
cow infected within 2-4mo after conception: calf infected with virus for life
53
viral-infected immunopathology
tissue injury mediated by host immune response to virus infection. the price paid by the host to clear viral infection
54
cytokines
broad and loose category of small proteins that are important in cell signaling. act as mediators and regulators of immune processes but also cause inflammation
55
monokines
cytokines produced by a mononuclear phagocytic cell
56
lymphokines
cytokines produced by activation lymphocytes (Th cells)
57
interleukins
cytokines that act as mediators between leukocytes
58
infectious bursal disease
virus replication causes atrophy of the bursa and a severe deficiency of B lymphocytes resulting in immunosuppression
59
inapparent viral infection
clinical signs an symptoms are not evident, too few cells may be infected, stimulate host immune response, possible source of virus spread
60
acute viral infection
short term infection, rapid clearance from the immune response
61
persistent viral infection
infectious virus is demonstrable continuously, whether or not there is ongoing disease
62
latent viral infection
infectious virus is not demonstrable except when reactivation occurs. ex. Herpesvirus
63
chronic viral infection
virus is continuously shed from or is present in infected tissue. ex. foot and mouth disease
64
slow intention
prolonged incubation period, lasting months or years
65
cytocidal effects
lysis & apoptosis
66
non-cytocidal effects
persistent infection
67
cell transformation effects
tumor cell formation
68
cytopathic/cytopathogenic effects
damage or morphological changes to host cells during virus invasion
69
pyknosis
degenerative condition of a cell nucleus marked by clumping of the chromosomes, hyperchromatism, and shrinking of the nucleus.
70
cell fusion (syncytium or polykaryon formation)
fusion of the plasma membranes of four or more cells to produce an enlarged cell with 4+ nuclei. prone to premature death
71
inclusion bodies
abnormal structures in a cel nucleus or cytoplasm or both, such as aggregates of proteins, having characteristic staining properties and associated with certain viral infections
72
negri bodies
ribonuclear proteins produced by the rabies virus
73
owl's eye inclusion bodies
seen in herpesviruses
74
adenovirus inclusion bodies
crystalline aggregates of virions in adenovirus infections
75
acidophillic staining
recognize/affinity for acid dyes, such as eosin. appear pinkish upon staining
76
basophillic staining
recognize/affinity for basic dyes, such as hematoxylin. appear purple-blue upon staining
77
apoptosis
programmed cell death. a mechanism of cell suicide that the host activates as a last resort to eliminate viral factors before progeny virus production occurs
78
intrinsic (mitochondrial) pathway
activated as a result of increased permeability of mitochondrial membranes subsequent to cell injury, such as that associated with a viral infection
79
extrinsic (death receptor) pathway
activated by engagement of specific cell-membrane receptors, which are members of the TNF receptor family. thus binding of the cytokine TNF to its cellular receptor can trigger apoptosis
80
ADCC
1- antibody binds Ag to surface of target cell 2- Fc receptor on NK cell recognized bound Ab 3- cross-linked Fc receptors signals the NK cell to kill the target cell 4- target cell dies by apoptosis
Virology@RUSVM
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