Lecture 6

Question 1

What is the difference between an infection and disease?

Answer 1

an infection is when a pathogen colonizes and begins to grow on a host

Question 2

What is the difference between an ectoparasite and an endoparasite?

Answer 2

ecto - lives on the surface of host

endo - lives inside of host

Question 3

What is the difference between a primary and opportunistic pathogen?

Answer 3

primary - causes disease in healthy hosts

opportunistic - causes disease only in immunocompromised patients

Question 4

How does the amount of lethal dose effect it’s virulence?

Answer 4

a lower lethal dose will mean that less of the microbe is needed to cause disease; more virulent

Question 5

What is biosafety level 1?

Answer 5

normal sterile techniques

Question 6

When is biosafety level 2 used?

Answer 6

for agents with little risk of aerosol transmission

Question 7

When is biosafety level 3 used?

Answer 7

in negative air pressure labs when working with virulent and inhalation transmitted agents

Question 8

When is biosafety level 4 used?

Answer 8

in complete isolation for agents that are highly virulent

Question 9

What is horizontal transmission?

Answer 9

transmission from one species to another via food, inhalation, contact, or vectors

Question 10

What is vertical transmission?

Answer 10

from parent to child

Question 11

What is accidental transmission?

Answer 11

a host who is not part of the normal infectious cycle unintentionally encounters that cycle

Question 12

What is immunopathogenesis?

Answer 12

the process of an immune response to a pathogen contributing to a cause of pathology and disease

Question 13

What is the difference between, an endemic, an epidemic and a pandemic?

Answer 13

endemic - disease is always present at low frequencies
epidemic - a sudden rise in disease over a short period of time
pandemic - an epidemic that occurs over a wide geographic area

Question 14

What are the traits the a pathogen needs to cause disease?

Answer 14

• gain host access
• find niche and colonize
• overcome host defences
• obtains nutrients and multiply
• exit

Question 15

What are the molecular koch’s postulates?

Answer 15

used to look at virulence gene
1 - phenotype is associated with pathogenic species
2 - inactivate of the gene should lead to loss of virulence or pathogenicity
3 - replacement of mutated gene should restore pathogenicity

Question 16

Where are virulence genes found?

Answer 16

on the pathogenicity islands in the chromosome

Question 17

What is the difference between exo and endo toxins?

Answer 17

exo - secreted to bacteria surroundings

endo - cell associated

Question 18

What mechanisms do bacterial exotoxins use?

Answer 18

damage cellular membrane, inhibit protein synthesis, and activate second messenger pathways

Question 19

What is the role of the B subunit in the AB toxin?

Answer 19

to bind to host cell

Question 20

What is the role of the A subunit in the AB toxin?

Answer 20

to have toxic activity