Descriptive Epidemiology Flashcards
adjusted mortality rates
mortality rates that take the weighted average of the specific mortality rates to eliminate distributions among different populations.
attack rate/incidence proportion
the proportion of the population that develops an illness during an outbreak.
case definitions
a set of standard criteria for classifying whether a person has a particular disease, syndrome or health condition. Ensures every case is equivalent.
case fatality rate
the rate/proportion of persons with a disease who die from it.
cause-specific morbidity rate
the morbidity rate from a specified cause for a population. # cases from cause/population at midpoint of time period.
cause-specific mortality rate
mortality rate from a specififed cause for a population. # deaths from cause/population at midpoint of time period.
cause-specific survival rate
survival rate from a specified cause for a population. # survivors from cause/population at midpoint of time period.
CDC
center for disease control;
cluster
aggregation of cases in a given area over a particular period without regard to whether the number of cases is more than expected.
common source outbreak
an outbreak that is continuous, but is not repeated or propagated. Does not include person to person contact, and all persons receive disease from a common source.
crude morbidity rate
morbidity rate from all causes of morbidity for a population. morbidity/total population.
crude mortality rate
mortality rate from all causes of death for a population. mortality/total population.
cumulative incidence
synonym for incidence proportion; is the proportion of an initially disease-free population that develops a disease over a period of time. # new cases during period/size of population at start of period.
disease registries
databases that contain demographical and health information of persons with a particular disease.
endemic
the normal rate of a disease for a particular population, which may be higher than other populations.
epidemic
sudden spread/occurrence of disease clearly in excess of normal expectancy. The community is defined, and the goal is to capture the disease as early as possible.
fertility rate
estimated average number of children per woman; the number of live births during a specified time interval.
frequency
used to identify disease occurrences; is counts in relation to size of the population.
incidence
the number of new and developing cases over a period of time.
incidence density
of new cases/total person time of population at risk
incidence rate
of new cases/person-time at risk for the disease.
incubation period
the time from exposure of an infectious agent to the onset of symptoms of an infectious disease.
infant mortality rate
deaths
infectivity
the ability of an infectious agent to cause infection, measured as the proportion of persons exposed to an infectious agent who become infected.
latency period
the time from exposure to a causal agent to onset of symptoms of a (usually noninfectious) disease.
live birth rate
also called natality; are population based measures of birth. # of live births/(total population/# people)
maternal mortality rate
ratio that measures mortality associated with pregnancy; # of deaths among women while pregnant or within 42 days of termination/# of live births in same time period.
MMWR
morbidity and mortality weekly report.
morbidity
departure, subjective or objective, from a state of psychological well-being.
mortality
measure of frequency of occurrence of death in a defined population during a specified interval. Midpoint of time period is often used.
neonatal mortality rate
birth up to but not including 28 days/# of live births during same period.
outbreak
an epidemic limited to a localized increase in the occurrence of disease; sometimes interchangeable with cluster.
pandemic
epidemic that spreads across continents.
pathogenicity
ability of an agent to cause disease after infection; proportion of persons infected by an agent who then experience clinical disease.
period prevalence
the amount of a particular disease, chronic condition, or type of injury present among a population at any time during a particular period.
person-time
the amount of time a person in a cohort study is observed and disease-free, often summed to provide the denominator for a person-time rate.
propagation outbreak
an outbreak that spreads from person to person rather than from a common source.
NNDSS
National notifiable diseases surveillance system
point source outbreak
outbreak that occurs at a specific time, often a specific date. All cases occur within one incubation period.
postnatal mortality rate
mortality rate for children from 28 days - 364 days. # deaths in a time period/# live births during same period.
prevalence
the amount of cases during a period in time.
prevalence rate
proportion of a population that has a particular disease, injury other health condition or attribute at a specified point in time or during a specific period.
point prevalence
proportion of the population that has a particular disease at a specified point in time.
proportion
ratio in which numerator is included in the denominator.
proportional mortality rate
proportion of deaths among a population attributable to a particular cause during a selected period. Each cause is represented as a percent. Denominator is all deaths, not just population among whom the deaths occurred.
rate
the relative frequency that an event occurs among a defined population per unit of time. # new cases or deaths during a time period/person-time or average population.
risk
the probability that an event will occur
secondary attack rate
a measure of the frequency of new cases of a disease among the contacts of known patients.
sentinel/index case
the first case of a disease.
active surveillance
going into a community and gathering information.
passive surveillance
waiting for reports from the community to be sent.
syndromic surveillance
looking for symptoms of a particular disease among patients.
virulence
the ability of an infectious agent to cause severe disease, measured as the proportion of persons with the disease who become severely ill or die.
WHO
world health organization.
