Pathology - Pathogenesis

Question 1

Infection

Answer 1

Any microbial growth not usually present in the host.

Question 2

Disease

Answer 2

Damage or injury that impairs host function.

Question 3

Why does the host have different levels of susceptibility and resistance to each pathogen variety?

Answer 3

Has the determinants of pathogenicity are different to each pathogen.

Question 4

Oppurtunisitc Pathogens

Answer 4

Pathogens usually harmless in healthy people, but virulent in immunocompromised hosts.

Question 5

How might normal flora cause disease to host.

Answer 5

If the host is immunocompromised

Question 6

What is pathogenicity measured by?

Answer 6

Pathogen virulence

Question 7

Virulence

Answer 7

The relative ability of a pathogen to cause disease

Question 8

How does virulence differ from pathogenicity

Answer 8

Virulence derives from host-pathogen interactions and is influenced by the host, pathogen and the envrionment.

Question 9

Lethal Dose 50

Answer 9

Describes number of pathogens it takes to kill 50% of animals in a test group.

Question 10

How is virulence measured?

Answer 10

LD50

Question 11

Why is it hard to determine LD50 of highly virulent pathogens?

Answer 11

Because highly virulent pathogens show little difference in pathogens it takes to kill 50% compared to 100%.

Question 12

Double Knock Out

Answer 12

Where two genes are knocked out simultaneously in an organism.

Question 13

Attenuation

Answer 13

Decreased or complete loss of virulence of a pathogen

Question 14

What might cause attenuation?

Answer 14

Weakly virulent pathognes in a culture have no selective advantage.

Question 15

Vectors

Answer 15

A living organism transmitting an infectious agent from an infected animal to a human or other animal.

Question 16

How might one deliver a heterogenous antigen to bacteria?

Answer 16

Vectors.

Question 17

How is attenuation artificially achieved?

Answer 17

Employment of recombinant DNA generating live-attenuated bacterial vaccine vectors through deletion of genes involved in virluence.

Question 18

What is an example of artifical attenuation?

Answer 18

Decreased phoP/phoQ system in salmonella.

Question 19

Glycocalyx

Answer 19

A polymer secreted by bcateria and coating its surface.

Question 20

Examples of bacterias adherence capabilities?

Answer 20

Glycocalyx, Fimbraie, Pili and Flagella, capsule and slime layer.

Question 21

Difference between slime layer and capsule?

Answer 21

S-layer are composed of polymers extending from the cell and capsule surround the cell, important in adhesion in most bacteria.

Question 22

Where are capsules most commonly employed?

Answer 22

Protecting pathogens against host defense.

Question 23

What is an example of utilising capsule in host infection?

Answer 23

Steptococcus Pneumonia virulence factor is the capsule.

Question 24

What does the S.Pneumonia capsule allow it to do?

Answer 24

Grow to vast numbers in host tissues with ability to initate host responses leading infection.

Question 25

Why might a capsule be essential in infeciton?

Answer 25

Nonencapsulated strains are often phagocytosed very easily.

Question 26

Where do pili bind specifically?

Answer 26

Host surface glycoproteins.

Question 27

How are Fimbraie used in E.Coli?

Answer 27

Causing Diarrhoea by enterotoxic strains containg genes for fimbriae colonization factor antigens adhering small intestine where E.Coli grow, causing diarrhea.

Question 28

EnteroToxin

Answer 28

A toxin produced that affects the intestine.

Question 29

Why is adherence important?

Answer 29

Provides nutrional acquistional capabilites and protection against envrionmental stress.

Question 30

What is the first stage in infection?

Answer 30

Invasion

Question 31

Invasion

Answer 31

The pathogens ability to enter host cells, spread and cause disease.

Question 32

Where does invasion often occur?

Answer 32

Skin/tissue damage or mucous rich regions.

Question 33

What do pathogens often do upon entry into a host?

Answer 33

Remain local where multireplicaiton and invasion occurs at a singularity.

Question 34

Baceremia

Answer 34

Viable bacteria in the blood.

Question 35

Septicemia

Answer 35

Life threatening reactions to infections.

Question 36

What is an important note in regards to infection?

Answer 36

It does not always cause host damage.

Question 37

What is infection dependent on?

Answer 37

Sufficient nutrients for the bacteria and adherence to surfaces.

Question 38

What is a major limiting growth factor for bacteria?

Answer 38

Iron.

Question 39

In regards to iron, how does a host respond to bacteria?

Answer 39

Transferrins and Lactoferrins are high affinity iron binders, sequestering it from the host.

Question 40

How can bacteria counter host iron sequesteration?

Answer 40

Siderophoresn.

Question 41

What is infection often associated with?

Answer 41

Biofilm formation.

Question 42

What is an example of biofilm formation in infection?

Answer 42

Dental plaques in tooth enamel by streptococci.