Vocab Flashcards
a factor (e.g., a microorganism or chemical substance) or form of energy whose presence, excessive presence, or in the case of deficiency diseases, relative absence is essential for the occurrence of a disease or other adverse health outcome
agent
any of a variety of proteins in the blood that are produced in response to an antigen as an immune response
antibody
any substance (e.g., a toxin or the surface of a microorganism or transplanted organ) recognized as foreign by the human body and that stimulates the production of antibodies
antigen
any of a group of viruses that are transmitted between hosts by mosquitoes, ticks, and other arthropods
arbovirus
the statistical relation between two or more events, characteristics, or other variables
association
a form of incidence that measures the proportion of persons in a population who experience an acute health event during a limited period (e.g., during an outbreak), calculated as the number of new cases of a health problem during an outbreak divided by the size of the population at the beginning of the period, usually expressed as a percentage or per 1,000 or 100,000 population
attack rate
a measure of the frequency of new cases of a disease among the contacts of known patients
secondary attack rate
systematic difference in the collection of data regarding the participants in a study (e.g., about exposures in a case-control study, or about health outcomes in a cohort study) that leads to an incorrect result (e.g., risk ratio or odds ratio) or inference
information bias
systematic difference in the enrollment of participants in a study that leads to an incorrect result (e.g., risk ratio or odds ratio) or inference
selection bias
having two data peaks
bimodal
a person or animal that harbors the infectious agent for a disease and can transmit it to others, but does not demonstrate signs of the disease
carrier
an instance of a particular disease, injury, or other health conditions that meets selected criteria
case
a set of uniformly applied criteria for determining whether a person should be identified as having a particular disease, injury, or other health condition
case definition
the proportion of persons with a particular condition (e.g., patients) who die from that condition
case-fatality rate
the first case or instance of a patient coming to the attention of health authorities
index case
the case or instance of a patient responsible for transmitting infection to others; the instance of a patient who gives rise to an outbreak or epidemic
source case
the enumeration of an entire population, usually including details on residence, age, sex, occupation, racial/ethnic group, marital status, birth history, and relationship to the head of household
census
the progression of an infectious agent that leaves its reservoir or host through a portal of exit, is conveyed by a mode of transmission, and then enters through an appropriate portal of entry to infect a susceptible host
chain of infection
the medical features (e.g., symptoms, medical examination findings, and laboratory results) that are used in a case definition
clinical criteria
a disease that has been manifested by its symptoms and features
clinical disease
an aggregation of cases of a disease, injury, or other health condition in a circumscribed area during a particular period without regard to whether the number of cases is more than expected
cluster
a range of values for a measure (e.g., rate or odds ratio) constructed so that the range has a specified probability (often, but not necessarily, 95%) of including the true value of the measure
confidence interval
the distortion of the association between an exposure and a health outcome by a third variable that is related to both
confounding
exposure or transmission of an agent from a source to a susceptible host through touching (e.g., from a human host by kissing, sexual intercourse, or skin-to-skin contact) or from touching an infected animal or contaminated soil or vegetation
direct contact
capable of being transmitted from one person to another by contact or close proximity
contagious
a two-variable table of cross-tabulated data
contingency table
the number of deaths attributed to a particular disease, injury, or other health condition during a specified period, divided by the number of new cases of that disease, injury, or condition identified during the same period
death to case ratio
application of quantitative methods to decision-making
decision analysis
personal characteristics of a person or group (e.g., age, sex, race/ethnicity, residence, and occupation)
demographic information
any factor that brings about change in a health condition or in other defined characteristics
determinant
association between an exposure and health outcome that varies in a consistently increasing or decreasing fashion as the amount of exposure increases
dose response
the direct transmission of an infectious agent by means of the aerosols produced in sneezing, coughing, or talking that travel only a short distance before falling to the ground
droplet spread
the constant presence of an agent or health condition within a given geographic area or population; can also refer to the usual prevalence of an agent or condition
endemic
an extrinsic factor (e.g., geology, climate, insects, sanitation, or health services) that affects an agent and the opportunity for exposure
environmental factor
the occurrence of more cases of disease, injury, or other health condition than expected in a given area or among a specific group of persons during a particular period
epidemic
a histogram that displays the course of an outbreak or epidemic by plotting the number of cases according to time of onset
epidemic curve
the traditional model of infectious disease causation having three components: an external agent, a susceptible host, and an environment that brings the host and agent together so that disease occurs
epidemiologic triad
the study of the distribution and determinants of health conditions or events among populations and the application of that study to control health problems
epidemiology
the aspect of epidemiology concerned with why and how a health problem occurs
analytic epidemiology
the application or practice of epidemiology to control and prevent health problems
applied epidemiology
the aspect of epidemiology concerned with organizing and summarizing data regarding the persons affected (e.g., the characteristics of those who became ill), time (e.g., when they become ill), and place (e.g., where they might have been exposed to the cause of illness)
descriptive epidemiology
having come into contact with a cause of, or possessing a characteristic that is a determinant of, a particular health problem
exposure
a negative test result for a person who actually has the condition similarly, a person who has the disease (perhaps mild or variant) but who does not fit the case definition, or a patient or outbreak not detected by a surveillance system
false-negative
a positive test result for a person who actually does not have the condition. Similarly, a person who does not have the disease but who nonetheless fits the case definition, or a patient or outbreak erroneously identified by a surveillance system
false-positive
an inanimate object that can be the vehicle for transmission of an infectious agent (e.g., bedding, towels, or surgical instruments)
fomite
any of a variety of measures (e.g., mortality rate) that indicate the state of health of a given population
health indicator
the observation that employed persons generally have lower mortality rates than the general population, because persons with severe, disabling disease (who have higher mortality rates) tend to be excluded from the workforce
healthy worker effect
a group of persons whose risk for a particular disease, injury, or other health condition is greater than that of the rest of their community or population
high-risk group
HIPAA
the Health Insurance Portability and Accountability Act, enacted in 1996, which addresses the privacy of a person’s medical information as well as postemployment insurance and other health-related concerns
a person or other living organism that is susceptible to or harbors an infectious agent under natural conditions
host
an intrinsic factor (e.g., age, race/ethnicity, sex, or behaviors) that influences a person’s exposure, susceptibility, or response to an agent
host factor
the constant presence at high incidence and prevalence of an agent or health condition within a given geographic area or population
hyperendemic
resistance developed in response to an antigen (i.e., an infecting agent or vaccine), usually characterized by the presence of antibody produced by the host
active immunity
the resistance to an infectious agent of an entire group or community (and, in particular, protection of susceptible persons) as a result of a substantial proportion of the population being immune to the agent
herd immunity
immunity conferred by an antibody produced in another host This type of immunity can be acquired naturally by an infant from its mother or artificially by administration of an antibody-containing preparation (e.g., antiserum or immune globulin)
passive immunity
a measure of the frequency with which new cases of illness, injury, or other health condition occurs among a population during a specified period
incidence
the time interval from exposure to an infectious agent to the onset of symptoms of an infectious disease
incubation period
invasion of the body tissues of a host by an infectious agent, whether or not it causes disease
infection
the ability of an infectious agent to cause infection, measured as the proportion of persons exposed to an infectious agent who become infected
infectivity
the separation of infected persons to prevent transmission to susceptible ones
isolation
a type of epidemiologic database, organized similar to a spreadsheet with rows and columns in which information from cases or patients are listed each column represents a variable, and each row represents an individual case or patient
line listing
a quantified relationship between exposure and a particular health problem (e.g., risk ratio, rate ratio, and odds ratio.)
measure of association
the manner in which an agent is transmitted from its reservoir to a susceptible host (see also transmission)
mode of transmission
any departure, subjective or objective, from a state of physiological or psychological health and well-being
morbidity
a measure of the frequency of occurrence of death among a defined population during a specified time interval
mortality rate
NHANES
The National Health and Nutrition Examination Survey, a representative survey of the civilian, noninstitutionalized US population conducted by the National Center for Health Statistics, designed to (1) estimate the proportion of the US population and designated groups with selected disease and risk factors; (2) monitor trends in selected behaviors, exposures, and diseases; and (3) study the associations among diet, nutrition, and health
a distribution represented as a bell shape, symmetrical on both sides of the peak, which is simultaneously the mean, median, and mode, and with both tails extending to infinity
normal distribution
a disease that, by law, must be reported to public health authorities upon diagnosis
notifiable disease
a measure of association used in comparative studies, particularly case-control studies, that quantifies the association between an exposure and a health outcome; also called the cross-product ratio
odds ratio
the occurrence of more cases of disease, injury, or other health condition than expected in a given area or among a specific group of persons during a specific period
outbreak
an outbreak that results from persons being exposed to the same harmful influence (e.g., an infectious agent or toxin). The exposure period can be brief or can extend over days, weeks, or longer, with the exposure being either intermittent or continuous
common-source outbreak
a common source outbreak in which the exposure period is relatively brief so that all cases occur within one incubation period
point-source outbreak
an outbreak that spreads from person to person rather than from a common source
propagated outbreak
an epidemic occurring over a widespread area (multiple countries or continents) and usually affecting a substantial proportion of the population
pandemic
the ability of an agent to cause disease after infection, measured as the proportion of persons infected by an agent who then experience clinical disease.
pathogenicity
a pathway into the host that gives an agent access to tissue that will allow it to multiply or act
portal of entry
a pathway by which an agent can leave its host
portal of exit
the proportion of cases identified by a test, reported by a surveillance system, or classified by a case definition that are true cases, calculated as the number of true-positives divided by the number of true-positives plus false-positives
predictive value positive
the number or proportion of cases or events or attributes among a given population
prevalence
a set of regulations based on the Health Insurance Portability and Accountability Act to protect the privacy of individually identifiable health information
privacy rule
a general term for measures of association calculated from the data in a two-by-two table, including risk ratio, rate ratio, and odds ratio
relative risk
the habitat in which an infectious agent normally lives, grows, and multiplies, which can include humans, animals, or the environment
reservoir
the probability that an event will occur (e.g., that a person will be affected by, or die from, an illness, injury, or other health condition within a specified time or age span)
risk
a sample of persons chosen in such a way that each one has the same (and known) probability of being selected
random sample
a sample whose characteristics correspond to those of the original or reference population
representative sample
change in physiologic status or in the occurrence of a disease, chronic condition, or type of injury that conforms to a regular seasonal pattern
seasonality
the ability of a test, case definition, or surveillance system to identify true cases; the proportion of people with a health condition (or the proportion of outbreaks) that are identified by a screening test or case definition (or surveillance system)
sensitivity
the ability or a test, case definition, or surveillance system to exclude persons without the health condition of interest; the proportion of persons without a health condition that are correctly identified as such by a screening test, case definition, or surveillance system
specificity
the range of manifestations a disease process can take (e.g., from asymptomatic to mild clinical illness to severe illness and death)
spectrum of illness
a study, usually observational, in which groups are compared to identify and quantify associations, test hypotheses, and identify causes. Two common types are cohort studies and case-control studies
analytic study
an observational analytic study that enrolls one group of persons with a certain disease, chronic condition, or type of injury (case-patients) and a group of persons without the health problem (control subjects) and compares differences in exposures, behaviors, and other characteristics to identify and quantify associations, test hypotheses, and identify causes
case-control study
an observational analytic study in which enrollment is based on status of exposure to a certain factor or membership in a certain group. Populations are followed, and disease, death, or other health-related outcomes are documented and compared
cohort study
a study in which a sample of persons from a population are enrolled and their exposures and health outcomes are measured simultaneously; a survey
cross-sectional study
an analytic study in which participants are enrolled before the health outcome of interest has occurred
prospective study
an analytic study in which participants are enrolled after the health outcome of interest has occurred. Case-control studies
retrospective study
without apparent symptoms
subclinical
public health surveillance in which the health agency solicits reports
active surveillance
monitoring of a person who might have been exposed to an infectious, chemical, radiologic, or other potentially causal agent, for the purpose of detecting early symptoms
medical surveillance
public health surveillance in which data are sent to the health agency without prompting
passive surveillance
a surveillance system that uses a prearranged sample of sources (e.g., physicians, hospitals, or clinics) who have agreed to report all cases of one or more notifiable diseases
sentinel surveillance
the monitoring of the frequency of illnesses with a specified set of clinical features among a given population without regard to the specific diagnoses, if any, that are assigned to them by clinicians
syndromic surveillance
a systematic canvassing of persons to collect information, often from a representative sample of the population
survey
a combination of symptoms characteristic of a disease or health condition; sometimes refers to a health condition without a clear cause
syndrome
any indication of disease noticed or felt by a patient
symptom
transfer of an agent suspended in the air, considered a type of indirect transmission
airborne transmission
indirect transmission by a vector in which the infectious agent undergoes biologic changes inside the vector as part of its life cycle before it is transmitted to the host
biologic transmission
transmission of an agent by a living intermediary; indirect
vectorborne transmission
transmission of an agent by an inanimate object; considered a type of indirect transmission; includes foodborne and waterborne transmission
vehicleborne transmission
an experimental study that uses data from individual persons. The investigator specifies the type of exposure for each study participant and then follows each person’s health status to determine the effects of the exposure
clinical trial
an experimental study that uses data from communities. The investigator specifies the type of exposure for each community and then follows the communities’ health status to determine the effects of the exposure
community trial
a clinical trial in which persons are randomly assigned to exposure or treatment groups
randomized clinical trial
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
virulence
a measure of the impact of premature death on a population, calculated as the sum of the differences between a predetermined minimally acceptable age (e.g., 65 years or current life expectancy) and the age at death for everyone who died earlier than that age
years of potential life lost (YPLL)
an infectious disease that is transmissible from animals to humans
zoonosis
NCHS
The National Center for Health Statistics, the US governmental organization responsible for national vital statistics and multiple national health surveys.
