Effects on Individuals and Populations

Question 1

What is who’s definition of health?

Answer 1

A state of complete, physical, mental and social well-being and not merely the absence of disease or infirmity.

Question 2

Definition of disease?

Answer 2

Any impairment that interferes with or modifies the performance of normal functions

Question 3

What are two forms of Costs?

Answer 3

Direct

Indirect

Question 4

Examples of direct costs

Answer 4

Mortality
Injury that has to be repaired
Injury that results in less efficiency
Direct loss of resources
Loss or reproduction

Question 5

Examples of indirect cost

Answer 5

Avoidance
Resistance - Ab production
Increased vulnerability to other harmful factors

Question 6

What is the currency used to measure “cost”

Answer 6

Energy

Question 7

Energy pathway

Answer 7

Ingested Energy –> Assimilated Energy
Assimilated Energy prongs into
- Respiration, maintenance, thermoreg, defense
- Production, growth, reproduction
- Storage - storage can return to assimilated

Question 8

2 basic rules about energy

Answer 8

An animal cannot use more energy than it can assimilate

If an animal uses more energy for one purpose, there is less available for another

Question 9

How can disease affect ingested energy?

Answer 9

Super occupied with disease that they dont eat as often

Question 10

How can chinchilla: dental abnormality affect the chinchilla

Answer 10

Teeth grow funny and cant eat well

Question 11

Cow: Johne’s disease

Answer 11

Malabsorption

Question 12

What is life time success measured in?

Answer 12

Fitness

Question 13

What is fitness determined by?

Answer 13

Combination of survival and fecundity

Question 14

Where does all disease begin?

Answer 14

Cellular level

• interference with cell’s energy or resource supply
• damage to the cell’s membrane

Question 15

4 forms of resistance

Answer 15

Avoidance
Physical barriers
Innate resistance
Acquired resistance

Question 16

Example of avoidance

Answer 16

If sheep are healthy they will not eat lush feed when near or covered in feces
If sheep are sick they will eat lush grass even though feces are present

Question 17

3 physical barriers

Answer 17

Intact skin
Gastric pH
Flow of urine

Question 18

What is the most important component of innate resistance?

Answer 18

Inflammation

Question 19

Two forms of repair

Answer 19

Regeneration - complete return of function

Scarring - Replacement with CT, diminish function

Question 20

What is the cause for most of the actual injury?

Answer 20

Body’s reaction to the agent
~inflammation
~immune response
~Repair and scarring

Question 21

What is a population

Answer 21

A group of individuals of the same species that live together in an area of sufficient size to permit normal dispersal and or immigration behavior and in which numerical changes are largely determined by birth and death processes

Question 22

5 Important features of a pop?

Answer 22

Size
Rate of contact
Spatial distribution
Sex and age composition
Rate of turnover (replacement)

Question 23

How doe effects of disease act at the population level?

Answer 23

Influencing survival or reproduction

Question 24

Two types of survival?

Answer 24

Direct mortality

Indirect mortality

Question 25

3 ways of indirect mortality?

Answer 25

Increased susceptibility to predation
Increased susceptibility to other diseases
Increased susceptibility to physical factors

Question 26

3 ways disease can affect repro

Answer 26

Injury to reproductive organs
Injury to fetus
Interference with reproductive behavior

Question 27

A population consists of 3 types of individuals with respect to any disease caused by a microparasite

Answer 27

Susceptible animals
Infected animals
Resistant animals

Question 28

3 results to infection

Answer 28

Recover and become resistant
Remain chronically infected
Die

Question 29

What is Ro?

Answer 29

The basic reproductive number (rate) of a disease
- the avg # of secondary infections that arise from introduction of one infected individual into a fully susceptible population

Question 30

What is Ro determined by?

Answer 30

Frequency of contacts

Proportion of contacts that result in transmission

Question 31

What must Ro = in order to become established in a pop?

Answer 31

Ro should = at least 1.

On avg, each infected individual has to infect at least on new individual or the disease will not become established

Question 32

Who was the most famous super-shedder?

Answer 32

Typhoid Marry

Question 33

What occurs as disease spreads within the pop?

Answer 33

The proportion of contacts that are with susceptible animals decreases
Ro no longer applies, uses Reff now

Question 34

Of maintenance, spillover and dead-end, which host do you want to target most?

Answer 34

Maintenance

Question 35

2 ways in which we manage or control disease?

Answer 35

Reduce the exposure to the agent or risk factor

Increase resistance