Chronic carrierLong period of being a carrierCaseinstance of a particular disease, chronic condition or type of injuryCase-patientA person in a case control study who has the disease or health condition under investigationCase definitionSet of standard criteria for determining whether a person has a particular disease or health condition. A case definition specifies clinical criteria and details of time, place and personCase-fatality rateThe proportion of people with a particular condition (case-patients) who die from that condition. In calculating case-fatality rates, the numerator is the number of people who die from the condition , and the denominator is the total number of people with the conditionCause of diaseaseA factor that directly influences the occurrence of a disease. Reducing such a factor in a population should reduce occurrence of the diseaseCensusThe enumeration of an entire population, usually including details on residence, age, sex, occupation, ethic group, marital status, birth history and relationship to head of householdChain of infectiona process that begins when an agent leaves its sourcec through a portal of exit, is conveyed by some mode of transmission and then enters through an appropriate portal of entry to infect a susceptible hostClassgrouping of observation of values of a variable. they are created for convenincce in analyzing frequencyClass boundariesthe values determining the upper and lower limits of classclass intervalThe span of values of a continues variable that lies between the class boundariesClinical criteriaThe symptoms and features of a diseasethat would be detected by physician analysisClinical diseaseA disease that has been manifested by its symptoms and featuresClusterAggregation of cases of a disease or other condition that are closely grouped in time and placec. The number of cases may or may not exceed the number expected and frequently the expected number is unknown.CohortWell-defined group of people who have had common experience or exposure and are then followed up as in a cohort study or prospective study to determine the incidence of new diseases or health conditionsCohort- birthgroup of people born during a particular period or yearConfidence intervalRange values for variable (e.g., a rate)confidence levelthe proportion of similarity constructed confidence intervals that include the parameter of interestConfidence limitsThe end points (min-max values) of a confidence intervalContagiousCapable of being transmitted from one person to another by contact or close proximityContingency tableTable cross-tabulated data allows for calculating associations. The 2-by-2 tables with case tabulated by exposure and outcome is the contingency table most commonly used in epiControlThe group of ppl without health problem under study in a case-control study a person in that group. For controls investigators choose people who are as similar as possible to the cases but without the health problem under study. In a case-control study the control group is compared with the case group to determine associations between exposure and outcomes and to test hypothesisCumulative frequencyIn a frequency distribution the number of proportion of case with a particular value or lessCumulative frequency curvea plot of the cumulative frequency rather than the actual frequency for each class interval of a variable. This type of graph is useful for identifying medians and quartiles and other percentilesDeath-to-case rationumber of deeaths attributed to a particular disease chronic condition or type of injury during a specified period divided by the number of new cases of that disease or injury identified during the same pdDemographic infopersonal charachteristics of age, sex, race residnce and occupation. Demographic info is used in descriptive epi to define the pop at riskdenominatorthe lower protion of a fraction. Epidemiologist use fractions to calculate rates, ratios. the denominator is usually the pop at risk although it may also be a measure such as person-time that quantifies the pop exposureDeterminantany factor that brings about change in a health condition or in other defined characteristicsDistributionthe complete summary of the frequency and pattern of health related characteristics and events in a popDot plotA visual display of the specific data points of a variableDroplet nucleithe residue of dried droplets that is easily inhaled and exhaled and may remain suspended in air for long periods and be blown over great distancesDroplet spreadThe direct transmission of an infectious agent by means of the aerosols produced in sneezing, coughing or talkingEndemic Health ConditionA disease, chronic condition or type of injury that is constantly present in a given geographic area or pop group, may also refer to the usual prevalence of a disease or conditionEnvironmental factorAn extrinsic factor, such as geology climare insects sanitation or health services that affects an agent and the opportunity for exposureEpidemicThe occurrence of more case of a particular type of disease chornic condition or injury than expected in a given area or among a specific group of people over a particular period of timeEpidemic curvea histogram that shows the course of an outbreak or epidemic by plotting the number of cases of a disease, chronic condition or injury according to time of onsetEpidemic periodthe time span of an epidemicEpidemiologic triadThe traditional model of infectious disease causation which has 3 components: External agent, susceptible host, environmentEpidemiologythe study of the distribution and determinants of health conditions or events in pop. and the application of this study to control health problemsEpi. analyticThe aspect of epi concerned with why and how a health problem occurs. Analytic epi uses comparison groups to provide baseline data so that associations between exposures and outcomes can be quantified and hypotheses about the cause of the prob can be testedEpi applied (field)The application or practice of epi to control and prevent health problemsEpi descriptiveThe aspect of epi concerned with gathering organizing and summarizing data on person time and placeEvaluationSystematic and objective examination of activities to determine how relevant and effective they areExposed groupGroup whose members have had contact with a cause of or possess a characteristic that is determinant of a particular health problemExposureComing onto contact with a cause of a disease, chronic condition injury or other attributes or events in a pop.Frequencyamount of occurrences of disease chronic ocndition injury or other attribute or event in a popFrequency distributionComplete summary of the frequencies of the values or categories of a variable. Often displayed in 2 column table with the individual values or categories in the left column and the number of observations in each category in the right columnFrequency polygongraph of frequencies distribution in which values of the variable are plotted on the horizontal axis and the number of observations are plotted on the vertical axis. Data points are plotted at the midpoints of the intervals and are connected with a straight lineGraphVisual display of quantitative data arranged in a system of coordinatesHealthState of complete physical, mental and social well being and not merely the abcence of disease or other infirmityHealth indicatorAny of a variety of measures that indicate the state of health of people in a defined popHealth info systemcombination of health statistics from various sources. Data from these systems is used to learn about health status, health care, provisions and use of services and the impact of services and programs on healthHigh Risk GroupGroup of people whose risk for a particular disease , health condition or type of injury is higher that that of the rest of their community or popHistogramVisual representation of the frequency distribution of continuous variable.The class intervals of the variable are grouped on a linearscale on the horizontal axis, and the class frequencies are on the vertical axis. Rectangles are drawn so that their bases equal the class intervals and their heights correspond to the class frequencies.HostPerson or other living organism that is susceptible to an infectious agent under natural conditionshost factoran intrinsic factor that influences an individuals exposure, susceptibility or response to an agentHyperendemic health problema disease, chronic condition or type of injury that is constantly present at a high incidencec and or prevalencehypothesisA supposition arrived at from observation or reflection that leads to refutable predictions any conjencture cast in a form that will allow it to be tested and refutedHypothesis alternativethe supposition that an exposure is associated with the health conditions under study. the alternative is adopted if the null hypothesis proves implausibleNull HypothesisThe supposition that an exposure is not associated with the health condition under study. the null hypothesis is the basis for most parametric tests for stat significanceActive immunityResistance developd in response to an antigen and usually characterized by the precence of antibody produced by the hostHerd immunityThe resistance of a group to an infectious agent. This group resistance exits because a high proportion of people in the group are immune too the agent. based on the # of people who are susceptible and the probability that they will come into contact with an infected person. By vaccinating large # of people in a pop to protect them from small pox health officials used herd immunity to control and eradicate the diseasePassive immunityConferred by an antibody produced in another host. This type of immunity can be acquired naturally by an infant from its mother or artificially by admin of an antibody-containing preparationIncidencea rate that measures the frequency with which a health problem such as a new injury or case of illness occurs in a pop. In calculating the numerator is the number of new cases occuring in the pop during a given period of time and the denominator is the total pop at risk during the timeincubation periodThe period following exposure, when pathologic changes are not apparent and ending with the onset of symptoms of an infectious diseaseIndividual dataData that have not been put into a frequency distributionInfectivitythe proportion of people who are exposed to an agent and become infectedInterquartile rangeThe central portion of a distribution calculated as the difference between the third quartile and and the 1st quartile. this range includes middle one-half of the observation is the set leaving one quarter of the observations on each sideLatency periodthe period following exposure when pathologic changes are not apparent and ending with the onset of symptoms of a chronic diseaseArithmetic meanmeasure of central tendency called the avg. the arithmetic mean is calculated by adding all the values in a group of measurements and dividing by the # of values in the groupGeometric meanthe mean or average of a set measured on a logarithmic scale