Important terms Flashcards
learn terms (146 cards)
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2
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What is epidemiology?
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The study of what causes disease, how disease is distributed, and how we can control the spread of disease.
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What are the two main classifications of epidemiology?
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- Classical vs clinical
- Descriptive vs analytic
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What does classical epidemiology focus on?
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Population-oriented health problems related to nutrition, environment, and human behavior.
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What is the focus of clinical epidemiology?
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Studies patients in health care settings to improve diagnosis, treatment, and prognosis.
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What type of epidemiology is heavily dependent on laboratory support?
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Infectious Disease Epidemiology.
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What does descriptive epidemiology examine?
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Time, place, and person data on a disease to determine trends.
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What is the objective of analytic epidemiology?
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Hypothesis testing to determine the cause of disease.
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Define ‘disease’ in epidemiological terms.
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Infection that results in signs (objective) and symptoms (subjective).
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What is an opportunistic disease?
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A disease that causes sickness when given the opportunity of a damaged or weakened immune system.
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What is a nosocomial disease?
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An infection that is acquired in a hospital.
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What does ‘iatrogenic disease’ refer to?
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An illness caused by medication or a physician.
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What is the incubation period?
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Time between exposure to an agent of disease and the first symptoms or signs.
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What is a latent infection?
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An infection where the agent is continuously present but can remain dormant before reactivation.
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What does asymptomatic mean?
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Displays no signs or symptoms but is infected and can carry the disease.
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What is susceptibility in epidemiology?
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To what extent a member of a population is able to resist infection.
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Define pathogenicity.
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The property of causing disease following infection.
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What is virulence?
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The property of causing severe disease.
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What is morbidity?
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The rate of disease in a population.
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What does mortality refer to?
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The rate of death in a population.
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What is the case fatality rate?
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The rate of death due to a disease in the diseased population.
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What does prevalence measure?
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The number of existing cases of disease in a given population.
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What is the difference between point prevalence and period prevalence?
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- Point prevalence: existing cases at a given point in time
- Period prevalence: total cases over a period of time
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What is incidence?
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The rate of new cases of disease in a given population over a period of time.
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What is the attack rate?
The number of people infected divided by the total sample.
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Define person-time.
The sum of the time during which each individual in a population was at risk for a disease.
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What is an index case?
The first case of a disease in a specific setting.
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What is etiology?
The cause of a disease.
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What does pathology study?
The science of the study and diagnosis of disease and injury.
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What is herd immunity?
A critical proportion of a population is immune to a disease, protecting the entire population.
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What is the purpose of outbreak investigation?
To identify and control the spread of disease outbreaks.
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List the first three steps of outbreak investigation.
* Prepare for field work
* Establish the existence of an outbreak
* Verify the diagnosis
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What is the purpose of constructing a working case definition?
To determine who has the disease or condition using standard criteria.
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What are confirmed cases in outbreak investigation?
Cases with lab confirmation combined with signs and symptoms.
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What is PulseNet?
A network of labs that helps identify foodborne, waterborne, and zoonotic disease outbreaks.
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What is the role of the public health laboratory in PulseNet?
To determine the type of bacteria and produce a DNA fingerprint.
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What is the significance of Whole Genome Sequencing (WGS) in PulseNet?
Provides a precise DNA fingerprint of the whole genome, distinguishing between different serotypes.
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What is the purpose of surveillance in public health?
To gain knowledge of patterns of disease for prevention and control.
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List the five steps of the surveillance process.
* Data Collection
* Data Analysis
* Data Interpretation
* Data Dissemination
* Link to Action
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What is passive surveillance?
Diseases are reported by healthcare providers.
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What is active surveillance?
Health agencies contact health providers seeking reports.
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What is syndromic surveillance?
Monitoring signs of disease as a proxy for the disease itself.
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What are Hill's Criteria for Causation?
* Strength of Association
* Consistency
* Specificity
* Alternative Explanations
* Temporality
* Dose-Response Relationship
* Biological Plausibility
* Experimental Evidence
* Coherence
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What are Koch's Postulates?
* Microbe present in abundance in disease cases
* Microbe isolated and grown in pure culture
* Cultured microbe causes disease in healthy organism
* Microbe reisolated from inoculated diseased host
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What are Evan's Postulates?
* Higher disease prevalence in exposed individuals
* More frequent exposure in diseased individuals
* Higher incidence in exposed individuals in prospective studies
* Normal distribution of incubation periods after exposure
* Spectrum of host responses following exposure
* Measurable host response after exposure
* More frequent disease in exposed individuals in experiments
* Reduction of risk with elimination of exposure
* Findings should make biological and epidemiological sense
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Define convalescent carriers.
Humans capable of spreading disease following a period of illness, thinking themselves cured.
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What are incubatory carriers?
Individuals who transmit pathogens immediately following infection but before symptoms develop.
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What is the Chain of Transmission Triad?
An external agent, host, and environment.
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What does 'Genetic' refer to in the context of disease traits?
Has inherited a disease trait but shows no symptoms
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What is meant by 'Transient/Temporary' in infectious disease transmission?
Someone who can transmit an infectious disease for a short amount of time
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What are the components of the Epidemiological Triad?
* Person
* Place
* Time
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What are the components of the Chain of Transmission Triad?
* An external agent
* A susceptible host for the disease
* The environment where the host comes into contact with the agent
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What is the purpose of Epidemiological Studies?
To investigate disease patterns and causes
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What distinguishes an Ecological study?
Looks for differences between groups of people with a shared characteristic rather than individuals
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What is a Cross Sectional study?
A survey or health questionnaire providing a 'snapshot in time'
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What does a Case-Control study compare?
People with and without disease to find common exposures
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What is the difference between a Cohort study and a Case-Control study?
Cohort studies compare people with and without exposures, while Case-Control studies compare people with and without disease
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What defines a Randomized Controlled Trial?
A human experiment that randomly assigns participants to an experimental or control group
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What are Quasi Experiments in epidemiological studies?
Research that lacks random assignment to treatment/control; participants are assigned based on non-random criteria
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List some advantages of a Trial study design.
* Most scientifically sound
* Best measure of exposure
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What are some disadvantages of a Cohort study?
* Time consuming
* Expensive
* Bad for rare diseases
* Possible loss of follow-up
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What is a 2x2 Table used for?
To show the number of people with or without exposure and with or without disease
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How is the Odds Ratio used in epidemiological studies?
It is used in case-control studies
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What does Relative Risk measure?
It is used in cohort studies
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Define Attack Rate.
The rate that a group experienced an outcome or illness equal to the number sick divided by the total in that group
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What is the Chi-Square used for in epidemiology?
To determine the statistical significance of the difference indicated by the relative risk or odds ratio
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What is an epi-curve?
A histogram that shows the course of an outbreak by plotting the number of cases according to the time of onset
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What characterizes a Point Source epidemic?
Occurs when people are exposed to the same exposure over a limited, well-defined period of time
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What distinguishes a Continuous Common Source epidemic?
Exposure to the source is prolonged over an extended period of time
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How does a Propagated epidemic differ from other types?
A case of disease serves later as a source of infection for subsequent cases
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What is Selection Bias?
Bias pertaining to how participants are chosen or retained in a study
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What is Performance Bias?
When researchers or participants alter their behavior, affecting data accuracy
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Define Measurement Bias.
Bias stemming from error in data collection
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What is Information Bias?
Bias stemming from errors in accuracy or lack of completeness in data
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What does External Validity measure?
The extent to which study results can be generalized to other settings
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What is Internal Validity?
The degree to which results are due to the intervention or treatment itself
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What is the Chain of Infection?
The process by which an agent leaves its reservoir, is transmitted, and enters a susceptible host
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What is an Agent in the context of disease?
A microbial organism with the ability to cause disease
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What is a Reservoir in infectious disease?
A place where agents can thrive and reproduce
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List the common Portals of Exit for pathogens.
* Skin
* Gastrointestinal tract
* Respiratory tract
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What are the three general categories of Mode of Transmission?
* Contact
* Vehicle
* Vector
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What is Contact Transmission?
Transmission through direct, indirect, or droplet contact
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How is Airborne Transmission characterized?
Occurs via droplets that remain suspended in the air
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What is Vector Transmission?
Transmission by an organism that does not enter the host
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What defines a susceptible host?
A person who cannot resist a microorganism invading the body
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What is the difference between Direct and Indirect Transmission?
Direct occurs through immediate contact; Indirect involves vehicles or vectors
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What are the types of direct transmission in infectious disease?
Kissing, biting, and contact with soil containing infectious agents.
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What is droplet spread?
An 'in your face sneeze or cough' that involves close and immediate exposure.
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What are the three types of indirect transmission?
Airborne, Vehicles, and Vectors.
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Define airborne transmission.
Transmission involving dust or droplet nuclei that remain suspended in the air.
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What is meant by biological vector?
A vector in which the infectious agent multiplies or changes life stage.
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What is a mechanical vector?
A vector that simply carries the infectious agent from one place to another.
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What is primordial prevention?
Intervention at the very beginning to avoid the development of risk factors.
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What is primary prevention?
Early intervention to avoid initial exposure to the agent of disease.
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What is secondary prevention?
Screening and treatment during the latent stage of disease.
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What is tertiary prevention?
Intervention during the symptomatic stage to slow or reverse disease progression.
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What is quaternary prevention?
Health activities to mitigate unnecessary or excessive intervention consequences.
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What is active immunity?
Immunity developed through exposure to a live pathogen or vaccination.
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What is passive immunity?
Short-term immunization by injection of antibodies not produced by the recipient's cells.
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What is innate immunity?
The body's natural, nonspecific defense system present from birth.
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Define herd immunity.
Protecting a community by immunizing a critical mass of its populace.
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What does the acronym FAT TOM stand for?
* Food * Acidity * Time * Temperature * Oxygen * Moisture
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What is the temperature danger zone (TDZ) for foodborne pathogens?
41 to 135 °F (5 to 57 °C).
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What are some prevention tactics for foodborne illnesses?
* Cook meat thoroughly * Don't cross-contaminate * Chill leftovers promptly * Clean produce * Report suspected illnesses
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What are the main causes of environmental quality-related illnesses?
Biological, chemical, and physical factors including pollution.
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What is the role of ground-level ozone in health problems?
Causes issues like asthma and worsened lung function.
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What are the characteristics of distributions in statistics?
Center, shape, and spread.
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Define central tendency.
A typical or middle value for a distribution.
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What is the mean?
The average of all values in a data set.
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What is the median?
The middle value that separates data into two halves.
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What is the mode?
The most frequently occurring value in a data set.
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What does skewedness refer to in a distribution?
The direction in which a distribution leans due to extreme values.
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What is the interquartile range (IQR)?
The difference between the 75th and 25th percentiles of a data set.
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What does standard deviation (SD) measure?
The spread of a data set in the same units as the original data.
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What is the 68-95-99.7 rule?
States that 68% of values fall within 1 SD, 95% within 2 SD, and 99.7% within 3 SD of the mean in a normal distribution.
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What is the infant mortality rate?
The ratio of deaths to births, typically expressed per 1000 or per million.
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What is statistical inference?
The process of inferring characteristics about a population from a sample.
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What are confidence intervals used for?
Estimating population attributes based on sample statistics.
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What does the infant mortality rate represent?
The ratio of deaths to births.
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How is the infant mortality rate expressed in epidemiology?
As a per-1000 or per-1 million ratio.
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What is statistical inference?
The process of inferring something about a population given a sample.
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What are confidence intervals used for?
To estimate population attributes given statistics from a sample.
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What does a confidence level of 95% indicate?
I am 95% certain that the interval captures the true population proportion/mean.
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What is a z table used for?
To contain common values for z-star.
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What is a t table used for?
To contain common values for t-star.
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What is the null hypothesis?
The default statement that there is no effect or association.
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What is the p-value in hypothesis testing?
The probability that the observed result occurred by chance if the null hypothesis were true.
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What threshold is generally used for significance in hypothesis testing?
0.05.
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What is a Type I error?
Rejecting the null hypothesis when it is true.
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What is a Type II error?
Failing to reject the null hypothesis when it is false.
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What does the power of a test represent?
The probability that the null hypothesis is rejected if it is false.
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What is sensitivity in disease testing?
The chance of testing positive if you do have the disease.
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What is specificity in disease testing?
The chance of testing negative if you do not have the disease.
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What is the purpose of a chi-square test?
To determine the difference between an expected value and an observed value.
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What is the formula used in a chi-square test?
(O−E)²/E for each cell.
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What does a t-test compare?
The means of two groups.
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What does a z-test compare?
Sample and population means or proportions with a known population variance.
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What is a paired t-test used for?
To compare multiple sets of data.
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What is Fischer's Exact Test used for?
To search for non-random associations between two categorical variables.
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What is the McNemar Test?
Similar to a Chi-Square but uses matched paired data.
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What is the purpose of the Cochran-Maentel-Haenszel Test?
To find the association between variables while controlling for confounding.
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What does ANOVA stand for?
Analysis of variance.
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What is ANOVA used for?
To compare variances of two or more samples.
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What is Artificial Immunity
A means by which the body is given immunity to a disease by intentional exposure to small quantities of it.
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What is Sufficient cause
In Rothman's Causual Pies, it is the whole pie.
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Fulminant
Severe and sudden onset of disease
