Section 7: Epidemiology Flashcards
What are the types of epidemiological studies
- descriptive
- analytical
- experimental
What is epidemiology
study of the distribution and determinants of health-related states or events in specified populations and the application of this study to control of health problems
What is etiology
the study of why things occur, the study of causation
Who is Edward Jenner
he made the observation that cowpox and smallpox are closely related
-prevention of smallpox by vaccinating with cowpox
Who is John Snow
made the observation that outbreak of cholera was linked to public water pump
-ended the epidemic by removing pump handle
What are the factors necessary for disease transmission
- pathogenic organism
- reactive host
- environmental conditions
What are the methods of transmission
- Direct
- indirect
- vector
What is direct transmission
person to person contact
-person can have clinical disease or subclinical
What is a carrier
individual that does not exhibit symptoms but harbors organism causing disease
What is indirect transmission
- contaminated food or water
- contact with inanimate objects (fomites)
What is vector transmission
- insects=notably mosquitos, flies
- arachnids=ticks
What are the patterns of host/pathogen relationships
- mutualistic
- commensal
- parasitic
What is a mutualistic relationship
type of symbiosis in which both organisms benefit
What is a commensal relationship
type of symbiosis in which there is no obvious benefit for organisms involved
What is a parasitic relationship
type of symbiosis in which only one partner benefits at the expense of the other partner
What is a reservoir for infection
long term host of pathogen of an infectious disease, usually without injury to itself and serves as a source from which other individuals can be infected
What is a primary reservoir
inanimate
- microbes are viable and multiply
ie: food, soil
What is a secondary reservoir
inanimate
- microbes are viable, but do not multiply
- air. soil
What is zoonosis
any infectious disease that can be transmitted from animals, both wild and domestic, to humans
What are the risk factors for disease
- age
- gender
- ethnicity
- nutrition
- pre-existing disease
- occupation
- food and water
What are patterns of disease
- endemic
- epidemic
- outbreak
- pandemic
What is a endemic
infection is maintained in the population without the need for external inputs. Constantly present in the population
What is an epidemic
disease that appears as new cases in the population in a period of time at a rate that substantially exceeds what is expected. Higher incidence
What is an outbreak
small and localized epidemic
What is a pandemic
global epidemic of an infectious disease that affects people or animals over an extensive geographical area
What is herd immunity
when a critical portion of a population is immune to a disease, either through natural immunity or vaccination, a phenomenon called herd immunity develops
-results in inability of an infectious disease to spread due to the lack of a critical concentration of susceptible host
What is morbidity
measurement of the incidence of a disease
- measures new events, so is also measure of risk
- calculate morbidity to determine how fast the disease develops in a population
What is prevalence
prevalence of a disease is the number of individuals affected at a specific time
What is attack rate
The attack rate is the proportion of people who are exposed to the disease during the outbreak who do become sick
What is mortality
death rate due to a given disease
-gives information about the severity of the disease
