Epidemic Curves and Determinants

Question 1

What is used to represent the number of new cases of disease over time?

Answer 1

Epidemic Curves

Question 2

What factors of disease can we learn from epidemic curves?

Answer 2

Most probable source of outbreak If pathogen is contagious If outbreak is ending or will continue Incubation period (sometimes) Outliers

Question 3

Should outliers in epidemic curves be considered or ignored?

Answer 3

Always consider! Early outliers can be early cases of the disease that weren’t noticed at first, but they can also be unrelated to the current outbreak.

Question 4

Early epidemic curves are based mainly on what?

Answer 4

Clinical signs and symptoms

Question 5

What factors will cause waves of infection to stop?

Answer 5

All susceptibles die or become resistant. Prophylaxis ends disease (vaccines)

Question 6

This curve features exposure followed by waves of secondary and tertiary cases of disease. What type of source is indicated?

Answer 6

Propagated source. Common with contagious diseases.

Question 7

The areas of low # cases between waves of disease indicate what?

Answer 7

Incubation period

Question 8

The following curve indicates what type of exposure to disease?

Answer 8

Common source, single point exposure. All animals are exposed at the same time from the same source.

Question 9

T/F: Epidemic curves such as the one featured are common with contagious disease.

Answer 9

FALSE

Contagious diseases produce a propagated source curve.

Question 10

If we know the point of exposure, can this curve tell us anything about the incubation period?

Answer 10

YES! We can determine the minimum, average, and maximum incubation times.

Question 11

This type of curve indicates what type of exposure?

Answer 11

Common source with intermittent exposure.

All animals are exposed to the same source, but at different times.

Question 12

What can this Common Source/Intermittent Exposure curve tell us about the incubation period?

Answer 12

Not really anything, since everyone is getting infected at different times.

Question 13

Host factors influencing the shape of an epidemiological curve:

Answer 13

Immunity or resistance

Direct transmission

Question 14

Pathogen factors influencing epidemiological curves:

Answer 14

Infectiousness of agent

Latent and incubation periods

Duration of infectivity

Question 15

T/F: Enviromnent doesn’t affect an epidemiological curve.

Answer 15

FALSE

Host factors, agent factors, AND environmental factors incluence the shape of the curve

Question 16

What’s up with endemic stability?

Answer 16

All factors influencing disease are relatively stable, resulting in little fluctuation in disease incidence over time.

Question 17

Factors that help determine the probability, distribution, or severity of a disease in an animal or population.

Answer 17

Determinants

Question 18

Health status is determined by the COMBINED ______.

Answer 18

Determinants of health

Question 19

Which is more important to health status, zip code or genetic code?

Answer 19

Zip code!

Question 20

5 Categories of health determinants for animals

Answer 20

Social environment (animal and human social factors)

Economic

Physical environment (food, water, shelter)

Animal individual characteristics

Etiologic agent

Question 21

If a determinant is a major contributing factor and is usually necessary for disease, it is called a _______ determinant

Answer 21

Primary

Question 22

Predisposing or enabling factors are called _______ determinants.

Answer 22

Secondary

Question 23

Age, breed and sex are examples are examples of ______ determinants

Answer 23

Intrinsic

Question 24

Housing and medical care are ______ determinants.

Answer 24

Extrinsic

Question 25

Spores in the soil and susceptible cattle are what kind of factors for anthrax disease?

Answer 25

Primary determinants, or necessary causes in Rothman’s model of diseases

Question 26

Mutations are agent based disease determinants, and include:

Answer 26

increased infectivity

Ability to infect new species

Aqcuisition of new toxins

Immune system invasion

Question 27

What 3 ways can antimicrobial resistance be obtained?

Answer 27

de novo

mutation

lateral transfer

Question 28

Environmental determinants include:

Answer 28

Demographics

Macroclimate

Microclimate

Housing/Crowding

Diet

Stress

Question 29

Diet is an ______ determinant, while nutrition status and BCS are _______ determinants.

Answer 29

Extrinsic/envorinmental

Intrinsic/host

Question 30

Genetic diseases are ______ determined by genotype, and genetic susceptibilities are ______ determined by genotype.

Answer 30

entirely

partially

Question 31

Why are certain breeds predisposed to certain diseases?

Answer 31

Similar genotypes within breeds

Breed determines size, color, etc