IDT231 Flashcards
is the study of the distribution and determinants of health-related states or events in specified population, and the application of this study to control of health problems.
Epidemiology
describes the distribution of diseases and health conditions – person, place, time
Descriptive epidemiology
finds out ‘causes’ or determinants – the three most common types of analytic study are: cohort studies, case-controlled studies and cross-sectional or prevalence studies.
Analytical epidemiology
is concerned with the prevention and control of health problems. The investigator controls an exposure of individuals in a population to a suspected factor, exposure randomly allocated to comparable groups, minimize confounding factors and outcome monitored, i.e. antibiotic clinical trial
Experimental (interventional) epidemiology
is the number of new infections divided by the number of those exposed – also known as incidence rate and case rate
attack rate
the difference between the true value and that established in the study – three types: selection, information, confounding
Bias
an individual who harbors a microorganism (agent) without clinical evidence of disease. Carriers may shed organisms into environment intermittently or continuously and shedding may lead to transmission
carrier
an individual who is recognized as having the condition of interest based upon the “case definition”.
case
a grouping of relatively uncommon events or diseases in time and/or space in numbers that are believed to be greater than those numbers expected by chance alone.
cluster
the multiplication of a microorganism at a body site or sites without evidence of infection. Colonization may or may not be a precursor for infection. Colonization may be a form of carriage and is a potential source of transmission
Colonization
the time in the natural history of an infection during which transmission may occur.
Communicable Period
an exposed individual who might have been infected through transmission of an infectious agent from another colonized or infected individual.
contact
having the potential for transmission
contagious
the presence of an agent on a surface or in a fluid, therefore, a potential source of transmission.
Contamination
Endemic
the usual level or presence of an agent/disease in a defined population during a given period
an unusual, higher-than-expected level of disease by an agent in a defined population in a given period – an increase over baseline rates
Epidemic
a graphic representation of the distribution of defined cases by the time of onset of their disease
Epidemic Curve
the time period over which the excess number of cases occurred
Epidemic Period
the level of an agent or disease which is consistently present at a high incidence and/or prevalence rate
Hyperendemic
All new cases
incidence
resistance of an individual to a specific agent, characterized by measurable and protective antibody or by cell-mediated immune response. Immunity may result from specific previous exposure with the agent. Immunity to some agents remains lifelong whereas for others it is short-lived.
Immunity
ratio of number of new infections or disease in a defined population to the number of individuals at risk in the population, in a given period of time.
Incidence Rate
the period between exposure to an agent and the first appearance of evidence of disease in a susceptible person
Incubation Period
the first case to be recognized in the series of transmissions of an agent in a susceptible population
Index Case
the successful transmission of a microorganism to a susceptible person with subsequent colonization, multiplication, and invasion. Infection may be clinically apparent or subclinical (no identifiable disease or symptoms
Infection
the physical separation of an infected or colonized individual (including contaminated body fluids and environmental materials) from the remainder of the at-risk population in an attempt to prevent transmission of a specific agent within the at-risk population
Isolation
disease
morbidity
death
mortality
all cases of disease including new (incident) and established cases
Prevalence
An animate or inanimate niche in the environment in which an infectious agent may survive and multiply to become the source of transmission to a susceptible individual
Reservoir
changes in measurable events over an extended period of time, also known as temporal trend.
Secular trend
Occurring irregularly or usually infrequently over a period of time
Sporadic
the ongoing systematic collection, analysis and interpretation of health care data essential to the planning, implementation and evaluation of health care practice.
Surveillance
routine reporting of special health events (notifiable diseases) to health authorities by health institutions and practitioners as mandated by law.
Passive surveillance
resource-intensive, more complete. Involves searching out various sources to solicit information on a regular basis
Active surveillance
– A condition of the person that indicates absence of protection against infection by an agent; often absence of specific antibodies.
Susceptibility
The method by which any potentially infecting/infectious agent is spread to another person.
Transmission
touching between people, projection of large droplets in coughing and sneezing before they fall to the ground (usually considered to be within one metre of the mouth).
Direct Transmission
vehicle-borne, airborne or vector-borne:
Indirect Transmission
water, food, syringes, which may act as an intermediate source of the infectious agent from a reservoir
Vehicle-borne
aerosols containing small (1-5 microns) particles may be suspended in air for long periods and inhaled into the lower respiratory tract.
Airborne
arthropods or other invertebrates may carry or transmit microorganisms usually through inoculation by biting
Vector-borne
If observation period begins as present time and continues into the future or until the appearance of disease
Prospective Study
Study starts today but assemble cohort based on exposure data collected sometime in the past (smoking according to survey done in 1980). By reviewing medical records between 1980 and today, the disease status can also be determined.
Retrospective Cohort Study (Historical Cohort):
