epi curves & determinants

Question 1

define latent period

Answer 1

when the microbe is replicating but isn’t enough for the host to become INFECTIOUS
*when the latent period is over, the animal is now infectious

Question 2

define incubation period

Answer 2

microbe is replicating but host isn’t symptomatic

-when the incubation period is over, the animal is not symptomatic

Question 3

t or f.

the latent period and incubation period always correlate

Answer 3

false

Question 4

define infectious

Answer 4

disease caused by the invasion and multiplication of a living agent in or on the host

Question 5

define infestation

Answer 5

invasion, but not multiplication, of an organism in or on a host

Question 6

define contagious

Answer 6

diseases transmissible from one human or animal to another via direct or airborne routes

Question 7

define communicable

Answer 7

disease caused by an agent capable of transmission by direct, airborne, or indirect routes from an infected person, animal, plant or inanimate reservoir.

Question 8

what do epidemic curves represent?

Answer 8

number of new cases of diseases over time

Question 9

what do epi curves tell you? (5 things)

Answer 9

1. probable source of the outbreak
2. if pathogen is contagious
3. if outbreak is ending or will continue
4. incubation period (sometimes)
5. about outliers

Question 10

what is each wave on the epi curve separated by?

Answer 10

incubation period

Question 11

define outliers

Answer 11

things the lie outside the normal range

Question 12

if you have a left outlier, what does this mean?

Answer 12

it’s an early case

can be due to: unrelation, short incubation period, person exposed early

Question 13

if you have a right outlier, what does this mean?

Answer 13

it’s a late case

can be due to: unrelation, long incubation period, or person exposed late

Question 14

what does the x and y axis represent on the epi curve?

Answer 14

x: time span
y: number of cases

Question 15

define propagated source epi curve

Answer 15

• exposure followed by waves of secondary and tertiary cases
• deals with a contagious disease

Question 16

define common source single point exposure epi curve

Answer 16

• all animals are exposed at once
• all are exposed to the same source of infection
• NOT contagious
• can determine the minimum, average, and maximum incubation period
• deals with only 1 incubation period!

Question 17

define common source with intermittent exposure epi curve

Answer 17

• animals are exposed at different times
• all are exposed to the same source
• incubation is NOT clearly shown

Question 18

the shape of the epi curve depends on what factors?

Answer 18

1. host
2. agent
3. environment

Question 19

define endemic stability

Answer 19

when all factors influencing disease are stable, resulting in little fluctuation in disease incidence over time

Question 20

give 3 examples of endemic stability

Answer 20

1. new cases occurring at a regular, low level
2. young individuals entering the population
3. old individuals dying or being removed

Question 21

define endemic/enzootic

Answer 21

its a low level disease

only have mild fluctuations

Question 22

define epidemic

Answer 22

its a high level disease

have stark changes

Question 23

define determinant

Answer 23

factors that help determine the probability, distribution, or severity of a disease

Question 24

define primary determinant

Answer 24

• major contributing factor
• MUST be there for disease to occur
• aka necessary causes in rothman’s model of diseases
• satisfy the “gotta have it” test

Question 25

define secondary determinant

Answer 25

factors that make the disease more likely

-predisposing or enabling factors

Question 26

define intrinsic determinants

Answer 26

determinants that are internal to the animal (age, breed, sex)

Question 27

define extrinsic determinants

Answer 27

determinants that are external to the animal (housing, medical treatment)

Question 28

what interactions make a determinant?

Answer 28

1. host (intrinsic)
2. agent (extrinsic)
3. environment (extrinsic)

Question 29

how can antimicrobial resistance be obtained?

Answer 29

1. de novo (starts from the beginning
2. through mutation
3. lateral transfer from another organism

Question 30

define microclimate and give an example

Answer 30

climate of a very small or restricted area

-disease in indoor dogs or cats

Question 31

define macroclimate and give an example

Answer 31

climate of a large area or multiple areas

-heartworm in the USA

Question 32

gentope determines what 2 things?

Answer 32

1. genetic diseases is ENTIRELY determined by genotype (primary determinant)
2. genetic susceptibility is PARTIALLY determined by genotype (secondary determinant)

Question 33

define each as being intrinsic or extrinsic:

1. diet
2. body condition score
3. nutritional status
4. giving a vaccine
5. being immune

Answer 33

1. extrinsic
2. intrinsic
3. intrinsic
4. extrinsic
5. intrinsic

Question 34

T or F

herd immunity protects individuals & the population

Answer 34

false.
it protects the population BUT it doesnt protect the individual. some non-immune individuals will become infected and some will be protected indirectly.