HMB342 Lecture 1 Introduction to Epidemiology

What is epidemiology?

the study of the determinants and distribution of disease in populations

What is an exposure?

defined as the cause of a health outcome

What is a risk factor?

defined as a factor which increases the risk for a health outcome to occur

What is the BEINGS model with respect to risk factor categorization?

Biologic & Behavioral

Environmental

Immunologic

Nutritional

Genetic

Services & Social/Spiritual

What are the five objectives of epidemiology in terms of a disease/outcome?

1) identify causes and risk factors

2) determine the spread

3) review the natural history and prognosis

4) evaluate existing and new strategies

5) develop public policy

What are some forms of primary prevention?

immunization ( process by which a person becomes protected against a disease)

vaccination ( act of administering the vaccine, usually via injection)

What are the two strategies for prevention in epidemiology?

1) population based approach

2) high-risk approach

What are the stages of disease

1) Normal- no disease, before disease starts

2) Preclinical phase- where disease is present, biologic onset of the disease but likely an asymptomatic period

3) Clinical phase- symptoms first appear, diagnosis given, and treatment/therapy given

4) clinical outcome

Which stages of disease are primary, secondary, and tertiary prevention associated with?

1) primary- no disease stage

2) secondary - pre-clinical stage

3) tertiary - after onset of symptoms/clinical phase

What is active immunity?

an individual's immune response where the body produces its own antibodies in response to a pathogen

What is passive immunity?

the transfer of antibodies to one person produced by another person

What is direct transmission?

mode of transmission where there is direct contact between an individual infected with a pathogen (agent) and a susceptible person (ie. HIV, HPV)

What is indirect transmission?

mode of transmission involving an agent being transmitted via an intermediate (ie. airborne transmission, vehicle transmission- drinking water, vector-borne transmission ie. ticks)

What is carrier status?

individuals who have the causative organism without clinical disease

What is the concept of herd immunity?

idea that if there is a large proportion of vaccinated/immune individuals, then there would be a small probability that a person infected with the disease encounters a susceptible individual