Lecture 7.1: Pathogenesis and Virulence

Question 1

what makes a disease reportable?

Answer 1

highly transmissible

Question 2

what is a self limiting pathogen?

Answer 2

only affects the person its in; does not spread to others

Question 3

what is a transmissible pathogen?

Answer 3

can be spread between individuals

Question 4

for what 3 reasons are diseases reported?

Answer 4

1. containment
2. lower transmission
3. reduction of exposure to others

Question 5

what is listeria/listerosis?

Answer 5

food borne infection

Question 6

what causes listerosis?

Answer 6

L. monocytogens

Question 7

listerosis can take the form of ____ pathogens, causing diseases such as: (5)

Answer 7

1. septocaemia
2. meningitis
3. gastroenteritis
4. encephalitis
5. mother to fetus transmission

Question 8

what is septocaemia?

Answer 8

blood borne infection

Question 9

what is meningitis caused by?

Answer 9

bacteria entering the CSF

Question 10

where does encephalitis occur?

Answer 10

in the brain

Question 11

listerosis is a threat for mother-fetus because it is able to __, making it highly virulent

Answer 11

cross central barrier

Question 12

listeria has mechanisms to interact with host cell during infection; what are some examples?

Answer 12

InlB, ActA LLO

Question 13

what is InlB?

Answer 13

protein made by bacteria

Question 14

InlB allows bacteria to be ____ (with respect to host cell)

Answer 14

internalized

Question 15

how does InlB help bacteria get internalized?

Answer 15

binds to MET and takes over to use clathrin to promote endocytosis

Question 16

what is MET?

Answer 16

tyrosine kinase

Question 17

MET is normally the receptor for ____

Answer 17

hepatocyte growth factor (HGF)

Question 18

in normal cell function, membrane __ is used to promote endocytosis

Answer 18

clathrin

Question 19

clathrin mediated endocytosis is used to ___ and ___

Answer 19

get nutrients and recycle the membrane

Question 20

what is listerlysin O? (LLO)

Answer 20

a pore forming toxin

Question 21

the expression of LLO is ___ regulated so that it is produced ___

Answer 21

tightly; at the exact moment the bacteria needs it

Question 22

listeria cannot replicate in ____ and must do so in ___

Answer 22

phagosome; host cell cytoplasm

Question 23

LLO is active at pH ___ (pH of __) and stops at pH ___ (pH of ___)

Answer 23

6 (phagosome); 7(host cytoplasm)

Question 24

once listeria is endocytosed, it is packaged in a ___

Answer 24

phagosome

Question 25

in order to replicate, what must happen to the engulfed listeria?

Answer 25

it has to escape the phagosome

Question 26

activity of LLO is critical to ____ in listeria

Answer 26

replication in host

Question 27

LLO functions by

Answer 27

dissolving the phagosome that contains listeria

Question 28

can listeria survive without LLO?

Answer 28

no

Question 29

disseminating pathogens are able to

Answer 29

spread out to other areas

Question 30

dissemination results in ____ pathogenesis

Answer 30

increased

Question 31

disseminating pathogens are associated with

Answer 31

many different diseases

Question 32

dissemination is made possible by ___ protein

Answer 32

Acet A

Question 33

what is Acet A?

Answer 33

host actin (f actin) modulating protein

Question 34

how does Acet A help in dissemination?

Answer 34

hijacks host actin to provide push for intra and intercellular movement

Question 35

the listeria that travels through cell membranes of adjacent cells while aided by actin is called ___

Answer 35

listeriopod

Question 36

dissemination causes the literiopod to have a ____ membrane

Answer 36

double

Question 37

upon invasion of listeriopod into adjacent cell, ___ is activated again

Answer 37

LLO

Question 38

what causes tuberculosis?

Answer 38

mycobacterium tuberculosis

Question 39

infection rates of M TB are climbing in ___ countries

Answer 39

developing

Question 40

M TB is endemic in areas with __ and ___

Answer 40

high population and reduced health care / medicine

Question 41

the infectious dose of M TB is ____ (around ___bacteria)

Answer 41

extremely low (1-10 bacteria)

Question 42

reasons why M TB is such a threat

Answer 42

1. drug resilient strains 2. treatment is long and expensive 3. many asymptic carriers 4. co-infection can be deadly (HIV) 5. existing vaccine is only for short term

Question 43

treatment of TB can take ___ months

Answer 43

3

Question 44

it is estimated that ____ people have TB (around ___ of the global population)

Answer 44

2 billion (1/3)

Question 45

TB is particularly deadly in a co-infection with ___

Answer 45

HIV

Question 46

what is the vaccine for TB?

Answer 46

bacillus calmate-guerin (BCG)

Question 47

what is the tubercule?

Answer 47

mass of cells involved in immune response that wall-in bacteria

Question 48

what is at the core of the tubercule?

Answer 48

macrophages

Question 49

the mass of cells that forms the tubercule is called a ___

Answer 49

granuloma

Question 50

the tubercule exists after ____ has occured

Answer 50

M TB replicates within a phagosome

Question 51

a tubercule develops ____ cells, which are dead

Answer 51

necrotic

Question 52

some of the bacteria in the tubercule surivive in a ___ form and can ___ in the presence of stress or another pathogen

Answer 52

latent; activate

Question 53

what is a benefit for the bacteria by being in a tubercule?

Answer 53

avoids active immune response

Question 54

what is a disadvantage for the host of keeping a bacteria in a tubercule?

Answer 54

can be exposed to sub-lethal conditions, gaining resistance and then later become active

Question 55

when TB replicates in a phagosome ___ and ___ are recruited

Answer 55

t cells and macrophages

Question 56

there are ___ within the M TB genome

Answer 56

pathogenicity islands

Question 57

mycobacteria are highly equipped with

Answer 57

virulence factors

Question 58

there are ___ pathogenicity islands in M TB required for its pathogenesis

Answer 58

6

Question 59

the __ strain is ___ components of the PAI and causes it to be ___ virulent

Answer 59

delta RDI BCG; missing; less

Question 60

in lowered virulence of the delta RDI BCG strain of M TB highlights

Answer 60

the importance of specific PAI for virulence of wild-type (normal) MTB