Epidemiology Exam 1

What is epidemiology?

A quantitative data-driven scientific discipline

What does epidemiology rely on?

Relies on a systematic and unbiased approach to the collection, analysis, and interpretation of data

Epidemiology is dependent on a working knowledge of probability, _________, and sound research methods?

statistics

What do we use to measure Epidemiology?

rates and ratios

_________/disroders

diseases

_________/activities that positively or negatively impact health

behaviors

epidemiology examines health related state or events on an ____________ (or community) level

aggregate

_________ frequency and patterns of health related state or events.

distribution

What are new cases of a disease/health event?

incidence

What are all cases of a disease/health event?

prevalence

What is disease/health event occurrence by person, place & time characteristics?

Descriptive Epidemiology

What causes and other factors influence the occurrence of health-related states or events?

Determinants

_________ uses epidemiological findings to propose and implement appropriate and practical public health interventions.

Application

What are examples of Application?

• policy changes

• awareness campaigns

• programming

What are examples of Determinants?

• Risk Factors

• Protective Factors

What is the ongoing, systematic collection, analysis, interpretation, and dissemination of the distribution and determinants of health related states or events?

Public Health Surveillance

_____ and ______ disease ______ (suspected outbreaks)

detect, report, clusters

What does Outbreak investigation/field epidemiology do?

respond to a report of a disease cluster (suspected outbreak)

What type of control is keeping the outbreak at bay and preventing additional cases?

Purpose

What is the process of determining the relevance, effectiveness, efficiency, and impact of (epidemiological) activities (especially surveillance and field investigation).

Evaluation

When you design an analytic study you want to…

study with a valid comparison group

What is policy development?

Develop policies based on evaluation findings

When did John Graunt publish the first report quantifying patterns of:

• birth

• death

• disease occurrence

1662 (London)

What did William Farr do in 1800’s London?

Systematically collect and analyze Britain’s mortality statistics

Who is the father of field epidemiology?

John Snow (1840/50’s - London)

What did John Snow do?

Studied cholera outbreaks

What is the purpose of outbreak investigation?

Control the outbreak and prevent additional cases

What was the first study of Epidemiology?

Determined 1 of 3 water pumps was causing a cholera outbreak.

• removal of the pump handle ended the outbreak

What was the 2nd study of Epidemiology?

(Re-examination of the first study), Examination of water supply companies, found significantly higher rates of cholera among residents served by the water supply company located downstream from the Thames River

Surveillance data is used to identify patterns among populations based on…

person, place, and time

Patterns are used to _______ hypotheses?

develop

what are person characteristics?

• Inherent (age, sex, race)

• biologic (immunity, vaccination status, co-morbidity)

• acquired (marital status)

What does co-morbidity mean?

• More than one disease/disorder is present in the same person at the same time

• usually chronic conditions

• coexisting or co-occurring conditions

• Co-morbid diseases are correlated, but they do not necessarily have a causal (cause and effect) relationship

How do we measure SES?

education achievement, occupation, family income

What does descriptive epidemiology do?

Develop create a hypothesis

what does analytic epidemiology do?

tests a hypothesis

what is a comparison group?

tells us how one study is different from another

what are the 2 types of analytic studies?

• Experimental (clinical trials)

• Observational (cohort, case control, cross-sectional)

What study is most often observed in a clinical setting?

experimental

how are participants grouped in experimental designs?

random (experimental and control group)

what study is tracked over time?

cohort

how are participants grouped in a cohort study?

exposure status

what study is comparing a group of ‘cases’ and ‘controls’?

case-control

how are participants grouped in case-control studies?

disease status

what study is a sample of individuals from a population that is enrolled in the study of their exposures and health outcomes?

cross-sectional

how are cross-sectional studies measured?

simultaneously

how are participants grouped in cross sectional cases?

they are not initally grouped

what type of study would take the most resources (time/money)?

1. cohort

2. cross-sectional

3. experimental

What is incubation period?

Stage of sub-clinical disease extending from the time of exposure to onset of disease symptoms

What are carriers?

Individuals who are infectious but have sub-clinical disease

What is Virulence?

The proportion of clinically apparent cases that are fatal

how would you calculate virulence rate?

numerator/denominator = dead cases/total cases

How would you calculate the virulence rate of COVID in Pitt County?

deaths from COVID in Pitt County/All COVID cases in Pitt County

How would you calculate the mortality rate of COVID in Pitt County?

deaths from COVID in Pitt County/Total population in Pitt County

How does transmission occur?

The infectious agent leaves its host through a portal of exit, is conveyed by some mode of transmission, and enters through a portal of entry to infect a susceptible host.

What are the 2 modes of transmission?

• Direct Contact

• Indirect Contact

What are the 3 types of Indirect Contact?

• Airborne - agents are carried by dust or droplets suspended in the air

• Vehicles - food, water, blood

• Vectors - mosquitoes, fleas, and ticks

What are the 3 types of Reservoirs?

• Human - may or may not know they are infectious

• Animal - carrier of rabies, trichinosis

• Environmental - plants, soil, and water

What is Public Health implications when referring to chain of infection?

Control or eliminate the agent and mode of transmission at its source (isolating those infected, promoting hand washing, filtering air, spraying for mosquitoes, vaccinations, masks)

What is sporadic disease?

occurs infrequently and irregularly (Ebola, Avian Flu)

What is an endemic?

the amount of disease that is usually present in the community (baseline level of disease)

What is a cluster?

an aggregation of cases grouped in time and place that are suspected to be greater than the number expected

What is an epidemic?

An increase, often sudden, in the number of cases of a disease above what is normally expected in that population

What is an outbreak?

Same definition as epidemic (increase in disease cases), but often used for a more limited geographic area

What is a pandemic?

An epidemic that has spread over several countries or continents, usually impacting a large number of individuals (COVID)

what are examples of portal of exit?

urine, feces, skin, legions, skin cuts (bodily fluids)