infectious disease epidemiology

Question 1

non-clinical disease state

Answer 1

pre-, sub- persistent carrier

Question 2

clinical disease state

Answer 2

signs and symptoms present

Question 3

T/F you can tailor intervention based on reservoir

Answer 3

true

Question 4

what are 4 methods of transmission?

Answer 4

horizontal direct
horizontal indirect
horizontal aerosol
vertical

Question 5

infectivity

Answer 5

• the ability of an agent to enter, survive and multiply in a host

Question 6

infectiousness

Answer 6

• the relative ease with which an agent (disease) is transmitted to other hosts
• function of portals of exit/entry, ability to survive away from host

Question 7

pathogenicity

Answer 7

-ability of the microorganism to induce disease

Question 8

virulence

Answer 8

-severity of the disease that occurs

Question 9

pre-clinical disease progresses to what?

Answer 9

clinical disease

Question 10

what is subclinical disease?

Answer 10

the disease is not clinically apparent, and will not become apparent

Question 11

what is persistent (chronic) disease?

Answer 11

failure to “shake-off” infection

-(previously clinical now subclinical)

Question 12

what is a carrier?

Answer 12

individual that harbors an agent, but does not respond immunologically or become clinically ill *but is infectious to others

Question 13

what are tools for temporary (transient) reservoirs?

Answer 13

temp. quarantine
vaccination
risk-group segregation

Question 14

what is a transient carrier?

Answer 14

clinical

non-clinical: pre/sub clinical

Question 15

what are tools for persistent carriers

Answer 15

test and removal
vaccinations
chemical prophylaxis (clear carrier state)

Question 16

what is a persistent carrier?

Answer 16

subclinical
chronic
long-term shedder

Question 17

all hosts will eventually one of what 2 things?

Answer 17

clear the infection or die

Question 18

method of transmission: horizontal direct

Answer 18

animal to animal

• droplet (secretions/excretions)
• fecal/oral
• venereal

Question 19

method of transmission: horizontal indirect

Answer 19

• fecal-oral contaminated vehicle
• vector
  
  • mechanical (fomite)
  • biologic - living organism with multiplication
• intermediate host (insect or snail, etc)
  
  • matures and changes in intermediate host

Question 20

method of transmission: horizontal air-borne

Answer 20

aerosol - smaller than droplets and travel more than short distances

Question 21

method of transmission: vertical

Answer 21

parent-to-offspring

• transovarian
• in utero
• colostral/milk

Question 22

transmissible

Answer 22

move to another animal

- may be direct or indirect

Question 23

non-transmissible: infectious agents

Answer 23

• do not move from one animal to the next

- environmental sources

Question 24

non-transmissible: noninfectious agents

Answer 24

do not move from one animal to the next

-toxins/poisons, immunologic dz, metabolic dz, nutritional deficiency

Question 25

antigenicity

Answer 25

-the degree to which an agent induces an immune response (antibodies or cell-medicated)