State

Confounding: A situation where an external factor is associated with both the exposure and outcome, which may distort the true relationship between them.

Epi curve: A graphical representation of the frequency of cases of a disease over time.

Conditional probability: The likelihood of an event occurring given that another event has already occurred.

Relative risk: The ratio of the risk of an event occurring in the exposed group compared to the unexposed group.

Attribute risk: The difference in the incidence of a disease between an exposed group and an unexposed group.

Attributable fraction: The proportion of a disease in a population that can be attributed to a specific risk factor.

Descriptive epidemiology: The study of the distribution and patterns of health-related conditions in populations.

Analytical epidemiology: The study of determinants of health-related states and diseases, often involving comparisons of different groups.

Determinants: Factors that influence the occurrence and distribution of health-related conditions.

Quantification: The process of measuring or counting the occurrence of health-related events or conditions.

Carrier: An individual who harbors a disease-causing organism but does not show symptoms of the disease.

Etiological agent: The biological agent responsible for causing a disease.

Reservoir: The natural habitat where an infectious agent lives, grows, and multiplies.

Vector: An organism that transmits a pathogen to a host.

Vehicle: An inanimate object or substance that indirectly transmits a pathogen to a host.

Direct horizontal transmission: The spread of a disease directly from one individual to another, without an intermediary.

Direct vertical transmission: The transmission of a disease from a parent to offspring, usually through childbirth or breastfeeding.

Case fatality rate (CFR): The proportion of individuals with a particular disease who die from that disease.

CFR formula: CFR = (Number of deaths from a disease / Number of diagnosed cases of that disease) × 100.

Rate difference formula: Rate Difference = (Rate in exposed group) - (Rate in unexposed group).

Relative risk formula: Relative risk = (Incidence rate in exposed group) / (Incidence rate in unexposed group).

Incidence formula: Incidence = (Number of new cases) / (Population at risk).

Disease transmission: The process by which a disease spreads from one individual to another or through an environment.

Contingency table: A matrix used to organize and analyze categorical data, especially for the comparison of different groups.

Risk factor: Any attribute, characteristic, or exposure that increases the likelihood of developing a disease or health condition.

Field investigation: A process where epidemiologists go into the field to study an outbreak and collect data to understand its cause.

Shoe leather epidemiology: The process of gathering data through direct investigation and contact, often by walking through affected areas.

Formative evaluation: Evaluation done during the development of a program to assess its feasibility and potential effectiveness.

Process evaluation: Evaluation that focuses on how a program is implemented, rather than its outcomes.

Summative evaluation: Evaluation conducted after a program has been implemented to assess its impact and effectiveness.

Linkages: The connections between various factors or organizations that can influence health outcomes.

Secular trends: Long-term patterns or trends in disease occurrence over time.

Experimental study: A study where the researcher actively manipulates an independent variable to observe its effect on a dependent variable.

Cohort study: A type of study that follows a group of people over time to examine how exposures affect the incidence of outcomes.

Prospective cohort study: A cohort study where participants are followed forward in time to see if they develop an outcome.

Retrospective cohort study: A cohort study that looks backward in time, using existing records to investigate exposures and outcomes.

Case-control study: A study that compares individuals with a disease (cases) to those without (controls) to identify potential risk factors.

Case-patient: A person who has been diagnosed with a particular disease during an outbreak or investigation.

Cross-sectional study: A study that examines a population at a single point in time to assess the prevalence of health conditions.

Epidemiological triad: A model describing the interaction between the agent, host, and environment in disease causation.

Agent: The microorganism or factor that causes disease.

Environment: The external factors (physical, social, or economic) that influence the spread and development of disease.

Causal pie: A model representing multiple factors (or "slices") that contribute to the development of a disease.

Necessary cause: A factor that must be present for a disease to occur but is not sufficient by itself to cause the disease.

Spectrum of a disease: The range of manifestations and severity of a disease from mild to severe.

Indirect transmission: The spread of disease through a vector or vehicle rather than direct contact.

Hyperendemic: A situation where a disease is consistently present in a population at a higher-than-expected level.

Outbreak: A sudden increase in the number of cases of a disease above what is normally expected.

Cluster: A group of cases of a particular disease that occur in a specific time or place, but not necessarily in excess of what is expected.

Common source outbreak: An outbreak in which all affected individuals are exposed to a common source of infection.

Point source outbreak: A common source outbreak where the exposure occurs over a brief period of time.

Continuous common source outbreak: An outbreak where the exposure occurs over an extended period, often linked to a single source.

Intermittent common source outbreak: A common source outbreak where exposure occurs in waves, with periods of exposure followed by periods of no exposure.

Propagated outbreak: An outbreak that spreads from person to person, often with multiple waves of infection.

Mixed epidemic: An outbreak that involves both a common source and propagated transmission.

Public health surveillance: The continuous, systematic collection, analysis, and interpretation of health-related data for planning, implementation, and evaluation of public health practices.

Variable: Any factor, trait, or condition that can vary or change across a population.

Attack rate: The proportion of people who become ill after exposure to a specific risk factor or event.

Prevalence rate: The proportion of individuals in a population who have a specific disease at a particular point in time.

Secondary attack rate: The proportion of exposed individuals who become ill during an outbreak.

Point prevalence: The proportion of individuals with a disease at a specific point in time.

Period prevalence: The proportion of individuals with a disease during a specified period.

Proportionate mortality rate: The proportion of deaths in a population that are attributable to a specific cause.

Years of potential life lost: A measure of premature mortality that estimates the number of years lost due to early death.

Measures of association: Statistical measures, such as relative risk or odds ratio, that describe the relationship between an exposure and an outcome.

Null hypothesis: The hypothesis that there is no effect or association between the variables being studied.

Alternative hypothesis: The hypothesis that there is an effect or association between the variables being studied.

Subclinical: A stage of a disease in which symptoms are not yet noticeable but the disease is still present.

Temporality: The concept that an exposure must precede an outcome in order to establish a causal relationship.

Bayes Theorem: A mathematical formula used to update the probability of a hypothesis based on new evidence.

Dose response: A relationship between the dose of an exposure and the magnitude of the response or outcome.

Molecular epidemiology: The study of the role of genetic and molecular factors in disease patterns and causes.

Genetic epidemiology: The study of genetic factors in the occurrence and distribution of diseases in populations.

Smallpox: A contagious and deadly disease caused by the variola virus, eradicated through vaccination.

Minamata disease: A neurological disease caused by mercury poisoning, resulting from industrial pollution in Minamata Bay, Japan.

Proportional mortality: The proportion of deaths in a population attributed to a specific cause.

Impairment: A loss of function or ability in an individual, often due to disease or injury.

Disability: A physical or mental condition that limits a person's ability to perform daily activities.

Handicap: A disadvantage experienced by an individual due to a disability, often related to social or environmental factors.

Health indicator: A measure used to assess the health status of a population, such as mortality rates or life expectancy.

Ecological study: A study that looks at the relationships between exposure and disease at the population level, rather than the individual level.

Thalidomide: A drug that caused birth defects when used by pregnant women, leading to its withdrawal from the market.

Field trials: Studies conducted in real-world settings to evaluate the effectiveness of interventions.

Random error: The variation in results due to chance, not systematic bias.

Selection bias: A bias that occurs when the selection of participants in a study is not random, leading to an unrepresentative sample.

Healthy worker bias: A bias that occurs when the study population consists of workers, who may be healthier than the general population.

Measurement bias: A bias that occurs when there is an error in how data is collected or measured.

Recall bias: A bias that occurs when individuals with a disease or condition remember their exposures differently from those without the disease.

Validity: The extent to which a study accurately measures what it intends to measure.

Infectious disease: A disease caused by microorganisms like bacteria, viruses, fungi, or parasites.

Bacteria: Single-celled microorganisms that can cause diseases such as tuberculosis or pneumonia.

Viruses: Tiny infectious agents that require a host cell to reproduce and can cause diseases like the flu or COVID-19.

Fungi: Eukaryotic organisms that can cause diseases like athlete’s foot or candidiasis.

Protozoa: Single-celled organisms that can cause diseases such as malaria or giardiasis.

Helminths: Parasitic worms that cause diseases such as schistosomiasis or tapeworm infections.

Prions: Infectious proteins that cause neurodegenerative diseases, like Creutzfeldt-Jakob disease.

Nonspecific mechanisms: General defense mechanisms, like physical barriers or inflammation, that the body uses against all pathogens.

Specific mechanisms: Immune responses that target specific pathogens, like antibody production.

Threshold proportion: The proportion of individuals in a population who must be immune for herd immunity to prevent the spread of a disease.

Plasmid: A small, circular piece of DNA in bacteria that can carry genes, including those for antibiotic resistance.

Emerging infectious disease: A disease that is newly identified or rapidly increasing in incidence or geographic range.

Re-emerging infectious disease: A disease that was previously under control but is now increasing in incidence or spreading to new areas.

Biostatistics: The application of statistical methods to biological, medical, or health-related research.

Community health: The health status and health issues affecting a specific population or community.

Environmental health: The study of how environmental factors, such as pollution or toxins, affect human health.

Global health: The health of populations worldwide, focusing on health issues that cross national borders.

Health policy and management: The development and implementation of policies aimed at improving public health and healthcare systems.

Health promotion and communication: Strategies and activities aimed at improving public health knowledge and behaviors.

Maternal and child health: The health of women during pregnancy and childbirth, and the health of children.

Minority health disparities: Differences in health outcomes between different racial, ethnic, or socioeconomic groups.

Social and behavioral health: The study of how social, cultural, and behavioral factors influence health.

The main objectives of disaster epidemiology: To assess the health impacts of disasters and provide evidence for response and recovery efforts.

CASPER: Community Assessment for Public Health Emergency Response, a method for assessing the needs of affected populations during a disaster.

Disaster: An event that causes significant harm or disruption to public health and safety.

Why data should be collected during a disaster: To understand the scope of the event, assess needs, and guide response efforts.

Public health surveillance: The ongoing, systematic collection, analysis, and interpretation of health data.

CDC mission: The mission of the CDC is to protect public health and safety by providing leadership and expertise in disease control and prevention.

CDC role: The CDC leads public health efforts to control infectious diseases, promote health, and prevent health disparities.

Passive surveillance: A surveillance method where health data is reported to health authorities without active solicitation.

Active surveillance: A surveillance method where health authorities actively seek out health data.

Dallas fire study: A study related to the health impacts of a specific event, such as a fire.

Cohort study: A study that follows a group of people over time to examine how exposures affect the incidence of outcomes.

Criteria for casual relationships: The conditions necessary to establish causality between an exposure and an outcome.

Specificity: The ability of a test or measure to correctly identify those without the disease.

Predictive value of positive: The likelihood that individuals with a positive test result truly have the disease.

Predicted value of negative: The likelihood that individuals with a negative test result truly do not have the disease.

Epidemiological ethics: Ethical considerations in conducting epidemiological research, such as informed consent and confidentiality.

Infectious disease: A disease caused by pathogens like bacteria, viruses, fungi, or parasites.

Specific mechanisms of host resistance: Immune responses that specifically target pathogens.

Case definition: A set of standard criteria for classifying whether a person has a particular disease or condition.

Odds ratio: A measure of association used in case-control studies to estimate the odds of exposure among cases compared to controls.

Crude death rate: The total number of deaths in a population divided by the population size.

Infant mortality: The number of deaths of infants under one year of age per 1,000 live births.

Child mortality: The number of deaths of children under five years of age per 1,000 live births.

Maternal mortality: The number of maternal deaths per 100,000 live births.

Ecological fallacy: The error of making inferences about individuals based on group-level data.

Experimental epidemiology: A branch of epidemiology where researchers manipulate variables to observe effects on health outcomes.

Randomized control trials: A study design in which participants are randomly assigned to treatment or control groups to assess the effects of an intervention.

Random error: Variability in data due to chance.

Sample size: The number of participants in a study, influencing the precision of results.

Systematic error: Error that consistently affects results in the same way, leading to bias.

How to control confounding: By using randomization, matching, stratification, or statistical adjustment to account for confounding variables.

Internal validity: The degree to which the results of a study accurately reflect the relationship between exposure and outcome in the study population.

External validity: The degree to which study results can be generalized to other populations or settings.

Probable case: A case that likely meets the clinical criteria for a disease but lacks confirmatory laboratory evidence.

Possible case: A case that is suspected based on symptoms but has limited evidence of the disease.

Confirmed case: A case where the diagnosis has been confirmed through laboratory tests or clinical criteria.

Suspect case: A case where the diagnosis is uncertain but meets the criteria for investigation.

Dose response: A relationship where an increase in exposure to a risk factor leads to a proportionate increase in the likelihood of an outcome.

Biological plausibility: The degree to which a causal relationship is consistent with current biological or medical knowledge.

Stratification: Dividing a population into subgroups to control for potential confounding variables.

Study based on definition of epidemiology: A study designed to investigate the distribution and determinants of health-related events in a population.

Serotyping: The process of identifying microorganisms based on the presence of specific antigens.

What can Epi curves indicate: Epi curves can indicate the pattern of disease spread, such as whether it is common-source or propagated.

Corynebacterium diphtheriae: The bacterium responsible for causing diphtheria.

Streptococcus pyogenes: A bacterium that causes a variety of infections, including strep throat and impetigo.

How do most bacteria reproduce: Most bacteria reproduce through binary fission, where a single cell divides into two identical cells.

What are virus particles composed of: Viruses are composed of a protein coat (capsid) and genetic material (either DNA or RNA).

Why are viruses not considered organisms: Viruses are not considered organisms because they cannot carry out metabolic processes on their own and require a host cell to reproduce.

How does fungi reproduce: Fungi reproduce both sexually and asexually through the production of spores.

Specific defenses: Immune responses that target specific pathogens, such as antibodies.

Nonspecific defenses: General defense mechanisms, like skin and inflammation, that protect against any pathogen.

Inflammatory response: A bodily response to injury or infection involving redness, heat, swelling, and pain.

Vaccine: A biological preparation that provides immunity to a specific disease.

Antimicrobials: Agents used to kill or inhibit the growth of microorganisms.

Bias: A systematic error in data collection, analysis, or interpretation that can lead to incorrect conclusions.

Comparison of rates: A method of comparing the frequency of an event across different populations or groups.

Comparison of rates formula: Comparison of rates is often expressed as a ratio of one rate to another, such as mortality rates between groups.

Primary prevention: Measures taken to prevent a disease or injury before it occurs, such as vaccination.

Secondary prevention: Early detection and intervention to prevent the progression of a disease.

Tertiary prevention: Interventions to reduce the impact of a disease or injury after it has occurred, such as rehabilitation.

Host factors: Characteristics of the individual that affect susceptibility to disease, such as genetics or immune function.

Agent factors: Characteristics of the disease-causing organism, such as its virulence or resistance to treatment.

Requirements for herd immunity: A sufficient proportion of individuals in a population must be immune to a disease, either through vaccination or previous infection, to protect the entire population from its spread.

Incubation period: The time between exposure to a pathogen and the appearance of symptoms.

Natality rates: The number of live births in a population over a given period, often expressed as births per 1,000 people.

Incidence rate: The rate at which new cases of a disease occur in a population.