Communicable diseases: introduction

Question 1

define: communicable disease

Answer 1

caused by an infectious agent, which is transmitted from one organism to another

Question 2

3 requirements/steps to infection

Answer 2

1. infectious agent must be present
2. infectious agent must be transmitted to the host
3. infectious agent must invade the host and multiply

Question 3

step 1?

Answer 3

infectious agent must be present

Question 4

what are the 4 types of infectious agents

Answer 4

bacteria
virus
parasite (roundworm, nematode)
fungi (and their toxic products)

Question 5

step 2?

Answer 5

infectious agent must be transmitted to the host

Question 6

define host

Answer 6

person/animal that the pathogen can survive and reproduce in, under normal conditions

Question 7

name the 4 modes of transmission

Answer 7

direct transmission
indirect transmission
-vehicle borne
-vector borne
-airborne

Question 8

direct transmission

• define
• examples
• how to control

Answer 8

source –> host
through sex, kissing, touching etc
gloves, condoms

Question 9

vehicle borne transmission

-define

Answer 9

source –> food, clothes, bed, cooking utensils –> individual

Question 10

airborne transmission

• define
• how to control

Answer 10

source –> dust particles/fungal spores –> individual

wear face mask

Question 11

vector borne

• define
• how to control

Answer 11

source –> vector (mosquito, bat) –> individual

clothes, nets, mosquito repellent

Question 12

does the environment play a role in infectious agent transmission?

Answer 12

yes

Question 13

describe some environmental factors

Answer 13

temperature, sanitation, air/water quality, house crowding

Question 14

step3:

Answer 14

the infectious agent must invade the host and multiply

Question 15

describe the first line of defence that must be invaded

Answer 15

skin

mucous membranes - GI and resp tract

Question 16

what happens once inside the body that causes infection

Answer 16

local cellular injury due to

• competitive metabolism
• toxin production
• intracellular replication
• antigen-antibody response

Question 17

what is a way that prevents the infectious agent from having deterious effects even once it’s in the internal environment?

Answer 17

immunisation and vaccination

Question 18

define: vaccination

Answer 18

injection of inactivated/weakened pathogens into person

Question 19

what microorganisms are vaccination effective for? what aren’t they?

Answer 19

bacteria and viruses. not parasites

Question 20

new vaccine being made?

Answer 20

malaria

Question 21

what macro process do vaccines enable?

Answer 21

herd immunity

Question 22

define: immunisation

Answer 22

physical response to the vaccination (injection of pathogens) which results in antibodies being made.

Question 23

define: virulence

Answer 23

strengh of disease

Question 24

define: infection

Answer 24

when an infectious agent invades the body and multiplies. results in local cellular injury - toxin production, competitive metabolism, intracellular replication and antigen-antibody response

Question 25

define: primary pathogen

Answer 25

pathogen itself can cause disease

Question 26

define: opportunistic pathogen

Answer 26

when immune system is weakened, then pathogen can cause disease

Question 27

acute vs chronic disease/

Answer 27

last for short or long time

Question 28

in relation to disease course | -what two terms relate to the person being able to SPREAD the disease (rather than show symptoms?)

Answer 28

period of latency | period of communicability

Question 29

define: period of latency

Answer 29

having infection, but not being able to spread

Question 30

define: period of communicability

Answer 30

having infection and being able to spread

Question 31

in relation to disease course | -what two terms relate to the person showing SYMPTOMS of the disease (rather than spreading it?)

Answer 31

incubation period | disease period

Question 32

define: incubation period

Answer 32

has infection but doesn't show symptoms

Question 33

define: disease period

Answer 33

has infection and shows symptoms

Question 34

define: source of infection

Answer 34

site from which pathogen is transmitted to host (eg food)

Question 35

define: reservoir of infection

Answer 35

site where pathogen can survive and multiply (eg. gut mucosa)

Question 36

notifiable diseases: what is the name of the scheme

Answer 36

national notifiable diseases surveillance scheme

Question 37

what does the national notifiable diseases surveillance scheme require

Answer 37

for particular communicable diseases to be reported and monitored by law

Question 38

``` what are they? 2xC 2xH 3xM 2 miscellaneous ```

Answer 38

``` cholera chicken pox hiv hepatitis measles mumps malaria tetanus infuenza/avian flu ```

Question 39

candidates for eradication must fit what 3 requirements

Answer 39

- effective intervention to interrupt transmission must exist - tests for it much be accurate (high sensitivity and specificity) - there must be no animal reservoir