Micro Final - Chapter 35

Front 1

host (definition)

Back 1

a larger organism that supports the survival and growth of a smaller organism

Front 2

parasites are organisms that...

(2 points)

Back 2

1. live on or within a host organism and are metabolically dependent on the host

2. cause disease

Front 3

infection is caused by...

Back 3

a parasite growing and multiplying within a host

Front 4

an infection may or may not result in

Back 4

overt infectious disease

Front 5

pathogen (definition)

Back 5

any parasitic organism causing infectious disease

Front 6

primary (frank) pathogen (definition)

Back 6

causes disease by direct interaction with a healthy host

Front 7

opportunistic pathogen (definition)

Back 7

may be part of normal flora and causes disease when it has gained access to other tissue sites or when the host is immunocompromised

Front 8

pathogenicity (definition)

Back 8

the ability of a parasite to cause disease

Front 9

the chain of events for a successful infection

(5 points)

Back 9

1. agent identity

2. virulence of agent

3. dose of agent

4. means of exposure to agent

5. susceptibility of host to agent

Front 10

the source of a pathogen can be _______ (human or other animal) or _________ (water, soil, food)

Back 10

animate, inanimate

Front 11

zoonoses (definition)

Back 11

infections passed from animals to humans

Front 12

reservoir (definition)

Back 12

a natural environment in which a pathogen normally resides

Front 13

a pathogen must ______ a host and ______ within it to cause _______

Back 13

contact, survive, disease

Front 14

to survive, a pathogen needs 3 things:

Back 14

1. a suitable environment

2. a source of nutrients

3. protection from harmful elements

Front 15

_________ allow a pathogen to outcompete host cells and resist their defences

Back 15

virulence factors

Front 16

5 pathogen survival strategies

Back 16

1. adhesions

2. enzymes

3. toxins

4. invasions

5. autoinducers

Front 17

toxigenicity (definition)

Back 17

the ability for microbes to produce toxins

Front 18

toxin (definition)

Back 18

a specific substance that damages the host

Front 19

intoxication (definition)

Back 19

diseases that result from entry of a specific preformed toxin into host

Front 20

toxemia (definition)

Back 20

a condition caused by toxins in the blood of the host

Front 21

infectious disease (definition)

Back 21

infection with viruses, bacteria, fungi, protozoa, and helminths

Front 22

signs (definition)

Back 22

objective changes in the body that can be directly observed

Front 23

symptoms (definition)

Back 23

subjective changes experienced by the patient

Front 24

disease syndrome (definition)

Back 24

set of characteristic signs and symptoms

Front 25

course of infectious disease

(5 points)

Back 25

1. initial exposure to microbes

2. incubation period

3. prodromal stage

4. illness

5. convalescent period

Front 26

incubation period

1. definition

2. intensity of symptoms

Back 26

1. period after pathogen entry, before signs and symptoms occur

2. low

Front 27

prodromal stage

1. definition

2. intensity of symptoms

Back 27

1. onset of signs and symptoms but not clear enough for diagnosis

2. increasing

Front 28

period of illness

1. definition

2. intensity of symptoms

Back 28

1. disease is most severe, death can occur in this period

2. increasing and peaks

Front 29

convalescent period

1. definition

2. intensity of symptoms

Back 29

1. signs and symptoms begin to disappear

2. decreasing

Front 30

infectious dose 50 (ID50) (definition)

Back 30

the number of pathogens that will infect 50% of an experimental group of hosts in a specified time. It varies with each pathogen

Front 31

lethal dose 50 (LD50) (definition)

Back 31

the dose that kills 50% of an experimental group of hosts in a specified time

Front 32

cytopathology (definition)

(2 points)

Back 32

1. cellular changes

2. can be used to observe cells in tissue culture for death rates rather than entire organisms

Front 33

the 2 main factors that effects host susceptibility

Back 33

1. defense mechanisms of host

2. pathogenicity of pathogen

Front 34

_____, ________, and _______ also play a role in host susceptibility to infection

Back 34

nutrition, genetic predisposition and stree

Front 35

extracellular pathogens (definition)

Back 35

grow outside cells in the blood or tissue fluids

Front 36

intracellular pathogens (definition) plus the 2 types

Back 36

grow and multiply within cells

also...

1. facultative intracellular pathogens can grow within or outside of cells

2. obligate intracellular pathogens can only grow inside cells

Front 37

pathogenicity islands (definition)

Back 37

major virulence factors on large segments on chromosomal and plasmid DNA

Front 38

pathogenicity islands ______ bacterial virulence

Back 38

increase

Front 39

pathogenicity islands are absent in ______

Back 39

nonpathogenic members

Front 40

pathogenicity islands: common sequence characteristic

(3 points)

Back 40

1. insertion-like sequences for mobility

2. G + C content different from bacterial genome

3. several open reading frames

Front 41

pathogenicity islands can be spread through...

Back 41

horizontal transfer of virulence genes to bacteria

Front 42

virulence factors are determined by:

(2 points)

Back 42

1. adherence and colonization

2. invasion

Front 43

the 1st step in disease is _____ and ______

Back 43

entrance and attachment

Front 44

the portal of entry can be...

(9 points)

Back 44

skin, respiratory system, gastrointestinal system, urogenital system, conjunctiva of eye, vector born, sexual contact, blood transfusion, or organ transplant

Front 45

adherence is mediated by special molecules called ______

Back 45

adhesions

Front 46

the site of microbial reproduction on or within a host is...

Back 46

colonization

Front 47

colonization does not necessarily result in tissue ______ or ______

Back 47

invasion or damage

Front 48

adherence structures

Back 48

fimbriae (adhesion molecules on bacteriums cell surface) bind complementary receptors sites on host cell surface

Front 49

infectivity (definition)

Back 49

ability to create a discrete point of infection

Front 50

invasiveness (definition)

Back 50

ability to spread to adjacent tissues

Front 51

penetration can be ______ or _______

Back 51

active or passive

Front 52

active penetration occurs through...

Back 52

lytic substances

Front 53

active penetration: mechanism

(3 points)

Back 53

1. attack the extracellular matrix and basement membranes of integuments and intestinal linings

2. degrade carbohydrate-protein complexes between cells

3. disrupt host cell surface

Front 54

passive penetration (ex. skin lesions, insect bites, wounds)

Back 54

spread to deeper tissues involves production of specific products and/or enzymes that promote spreading

Front 55

once in the ______ system, bacteria have access to all ______ and _______

Back 55

circulatory, organs, systems

Front 56

bacteremia (definition)

Back 56

presence of viable bacteria in the blood

Front 57

septicemia (definition)

Back 57

pathogens or their toxins in the blood

Front 58

invasion ______ among pathogens

Back 58

varies

Front 59

exotoxins (definition)

Back 59

soluable, heat-labile, proteins

Front 60

exotoxins are secreted into _____ as the pathogen ______

Back 60

surroundings, grows

Front 61

most exotoxin producers are _____

Back 61

Gram-negative

Front 62

exotoxins often travel from the _____ to other _____ or ______ where they exert their effects

Back 62

site of infection, tissues, cells

Front 63

exotoxins are usually synthesized by specific _____ that have ______ in their plasmids or prophage DNA

Back 63

bacteria, toxin genes

Front 64

exotoxins are among the most _____ substances known to man

Back 64

lethal

Front 65

_____ are highly immunogenic

Back 65

exotoxins

Front 66

exotoxins stimulate the production of _____

Back 66

neutralizing Ab (antitoxins)

Front 67

exotoxins are chemically _____ to form ______

Back 67

inactivated, immunogenic toxoids

Front 68

4 types of exotoxins

Back 68

1. AB exotoxins

2. specific host site exotoxins

3. membrane-disrupting exotoxins

4. superantigens

Front 69

AB exotoxins are composed of 2 subunits

Back 69

1. A subunit: responsible for toxic effect

2. B subunit: binds to specific target cell

Front 70

superantigens stimulate ~30% of _____ of the immune system

Back 70

T cells

Front 71

superantigens stimulate T cells by causing the T cells to _____ and release _____

Back 71

overexpress, ctyokines

Front 72

superantigens stimulate T cells resulting in failure of multiple ______ allowing time for the microbe to ______

Back 72

host organs, disseminate

Front 73

an example of an endotoxin is...

Back 73

lipopolysaccharide (LPS)

Front 74

LPS in ______ cell wall can be ____ to specific hosts

Back 74

Gram-negative, toxic

Front 75

LPS is called an ______ because it is an ________ part of the bacterium and released when organisms _______. Some is also released during ______

Back 75

endotoxin, endogenous, lyses, multiplication

Front 76

endotoxins are...

(3 points)

Back 76

1. heat stable

2. toxic

3. weakly immunogenic

Front 77

general system effects of endotoxins

Back 77

fever, weakness, diarrhea, inflammation, intestinal hemorrhage

Front 78

endotoxins bring about these effects _____

Back 78

indirectly

Front 79

endotoxins interact with host _____ and _____, activating host _____

Back 79

molecules, cells, systems

Front 80

endotoxin interaction with ______ causes the release of endogenous pyrogen which induces _______

Back 80

macrophages, fever

Front 81

endotoxin binding to LPS-binding protein causes the release of ______ leading to _____ or _____

Back 81

cytokines, tumor necrosis, septic shock

Front 82

mycotoxins are _____ metabolites of _____

Back 82

secondary, fungi

Front 83

mycotoxins are common _____ of food crops

Back 83

contaminants

Front 84

biofilm growth is _______ different from planktonic growth

Back 84

physiologically

Front 85

biofilm development...

1. may cause ____ infection

2. _____ virulence

3. become ____ sensitive to antibiotics

4. make cells in biofilm ____ resistant to host defences

Back 85

1. chronic

2. increases

3. less

4. more

Front 86

most microbes are ______ before they can cause _____ due to the immune system

Back 86

eliminated, disease

Front 87

______ pathogens evade the immune system

Back 87

successful

Front 88

resisting host defenses:

capsules _____ phagocytosis

Back 88

prevent

Front 89

resisting host defenses:

infection of _____ cells, ______ their function

Back 89

immune system, diminishing

Front 90

resisting host defenses:

____ with adjacent cells to prevent _____ to antimicrobial proteins in the _____

Back 90

fuse, exposure, host

Front 91

resisting host defenses:

mutations change ______ site or ____ expression of _______ through ______ or ______

Back 91

antigen, alter, antigens, downregulation, phase variation

Front 92

resisting host defenses:

produce _____ that resemble host _____

Back 92

substances, tissue

Front 93

resisting host defenses:

produce _____ that degrade host _____

Back 93

proteases, proteins

Front 94

resisting host defenses:

production of ____ proteins to bind available neutralizing ______

Back 94

decoy, antibodies

Front 95

resisting host defenses:

_____ O-chains to prevent host _____ or _____

Back 95

lengthened, detection, lysis

Front 96

some survive inside host cells by ____ themselves from cell to cell using host _____

Back 96

ejecting, actin

Front 97

there are 5 main modes of transmission

Back 97

1. airborne

2. contact

3. vehicle

4. vector borne

5. vertical

Front 98

evidence suggest a _____ between mode of transmission and degree of virulence

Back 98

correlation

Front 99

direct contact is ____ virulent

Back 99

less

Front 100

vector borne is ____ virulent in human host but relatively ____ in vector

Back 100

highly, benign

Front 101

transmission alone is not enough for _____ to occur

Back 101

infection

Front 102

tropism (definition)

Back 102

pathogen must make contact with the appropriate host tissue

Front 103

transmission of infection can be _____ or _____

Back 103

direct, indirect

Front 104

4 modes of direct infection:

Back 104

1. horizontal contact (kissing, sex)

2. airborne droplets

3. vertical contact (pregnancy)

4. vector (insect)

Front 105

3 modes of indirect contact (vehicles):

Back 105

1. fomites

2. food, water, biological products

3. airborne (droplet nuclei)

Front 106

airborne transmission (definition)

Back 106

pathogen suspended in the air and travels about 1 meter

Front 107

droplet nuclei (definition)

Back 107

small particles that can remain airborne for a long time and can travel long distances. They are usually propelled from the respiratory tract of source organism by sneezing, coughing or vocalization

Front 108

_____ are also important route of airborne transmission

Back 108

dust particles

Front 109

contact transmission (definition)

Back 109

the coming together or touching of source/reservoir and host. It can be direct or indirect

Front 110

vector-borne transmission: external transmission (definition)

Back 110

passive carriage of pathogen on body of vector; no growth of pathogen during transmission

Front 111

vector-borne transmission: internal transmission (definition)

Back 111

carried within a vector. There are 2 types of internal transmission: harborage and biological

Front 112

harborage transmission (definition)

Back 112

pathogen does not undergo changes within the vector

Front 113

biological transmission (definition)

Back 113

pathogen undergoes changes within the vector

Front 114

vertical transmission (definition)

Back 114

occurs when the unborn child acquires a pathogen from an infected mother

Front 115

vertical transmission is ___ as common as horizontal transmission

Back 115

not

Front 116

babies born with an infectious disease are said to have a ______

Back 116

congenital infection

Front 117

examples of congenital infections acquired through vertical transmission

(4 points)

Back 117

1. gonorrhea (especially in the eyes)

2. herpes

3. german measles

4. toxoplasmosis