Basic Epi

Question 1

epidemiology

Answer 1

study of distribution and determinants of health or disease in a population, and application of this study to control health problems

it is a young science!

Question 2

objectives of epi

Answer 2

1. determine etiology or cause of disease + risk factors that increase risk
2. determine extent of disease in community
3. study natural history and prognosis of disease
4. evaluate existing and new preventive and therapeutic measures and modes of healthcare delivery
5. provide foundation for public policy and decisions on environmental problems

Question 3

3 types of prevention

Answer 3

1. primary
2. secondary
3. tertiary

Question 4

primary prevention

Answer 4

prevent initial development
EX: immunization, limit exposure to risk factor

Question 5

secondary prevention

Answer 5

early detection of existing disease to reduce severity and complications
EX: screen for cancer

Question 6

tertiary prevention

Answer 6

reduce impact of disease
EX: rehab for stroke

Question 7

surveillance

Answer 7

ongoing, systematic collection, analysis, and interpretation of data essential to planning, implementing and evaluating public health practices, and dissemination of info

Question 8

what is surveillance useful for

Answer 8

identify changes in disease
planning
help identify risk factors

Question 9

surveillance methods

Answer 9

passive
active
sentinel

Question 10

passive surveillance

Answer 10

data from doctors, labs, hospitals
cheap, but may have underreporting

Question 11

active surveillance

Answer 11

data actively collected during outbreaks by surveys and medical professionals
expensive and labor intenstive

Question 12

sentinel surveillance

Answer 12

early warning system by focused activities on early detection
cheap and fast, but only works for some diseases

Question 13

prevalence

Answer 13

disease burden
number of cases in pop. at point / period of time
accounts for duration
snapshot of time

Question 14

prevalence =

Answer 14

incidence x duration

Question 15

duration includes

Answer 15

death and cure rate

Question 16

incidence

Answer 16

disease risk
new case / ppl at risk x 1000
measures risk or probability individual will get disease in a given period of time

Question 17

confounding

Answer 17

other risk factors that impact disease

Question 18

how can we control for confounders

Answer 18

in data analysis
in study design

Question 19

bias

Answer 19

any systematic error in design, conduct, or analysis that results in mistake estimate of exposure’s effect on risk of disease

Question 20

endemic

Answer 20

natural/normal occurrence of disease in certain area
EX: malaria in Africa

Question 21

epidemic

Answer 21

occurrence of disease beyond what is expected or considered normal (must measure normal)
EX: smallpox, measles, polio

Question 22

pandemic

Answer 22

epidemic that occurs over wide area
EX: global flu, AIDS, COVID-19

Question 23

if disease occurrence is greater than epidemic level, we investigate

Answer 23

who was attacked (sex, age race)
when did it occur (season, trends overtime)
where did cause arise (clusters? EX: Lyme disease, West Nile Virus, COVID-19)

Question 24

infectious disease 2 types of transmission

Answer 24

direct and indirect transmission

Question 25

direct infectious disease transmission

Answer 25

physical contact, touch, sex, droplets

Question 26

indirect infectious disease transmission

Answer 26

contaminated surfaces/objects:
air, water, food
vectors: mosquitoes, flies, ticks, pests

Question 27

basic reproduction number

Answer 27

R0

Question 28

R0 describes

Answer 28

contagiousness of infectious agents
OR
number of secondary cases 1 case would produce in a completely susceptible population

Question 29

3 parameters for R0

Answer 29

1. duration of contagiousness after a person is infected
2. likelihood of infection per contact btwn. susceptible and infectious person
3. contact rate

Question 30

R0 only applies when…

Answer 30

everyone in population is completely vulnerable

Question 31

what is required for whole population to be vulnerable

Answer 31

no one has been vaccinates
no one had disease before
there’s no way to control spread of disease

Question 32

R0 is NOT:

Answer 32

a biological constant, a rate over time, or a measure of severity

Question 33

can R0 measure severity?

Answer 33

no!

Question 34

incubation period

Answer 34

internal from receipt of infection to time of onset of clinical illness

Question 35

carrier status

Answer 35

individual harbors organism, but isn’t infected by symptoms or serologic studies
CAN infect others
EX: Typhoid Mary (chef infected others for years)

Question 36

herd immunity

Answer 36

resistance of a group to an attack by a disease to which a large proportion of group are immune (EX: polio)