SCIOLY Disease Detectives: cumulative review

Epidemiology

the study of the origin and causes of diseases in a community, the scientific method of investigation problem-solving used by disease detectives (epidemiologists, laboratory scientists, statisticians, physicians, and other healthcare professionals) to get to the root of health problems and outbreaks in a community

The Role of Epidemiology in Public Health

understanding disease patterns and frequencies in order to more efficiently analyze future epidemics

Subclinical

incubation period, in the system but not taking effect

Clinical

past the incubation period, in the system and attacking the body

Incubation Period

in the body system but not taking effect

Stage of Susceptibility

a disease is not in the system but is during an outbreak

Point of Exposure

the moment when the disease is contracted

Pathologic Changes

early symptoms that indicate the disease is in the body

Usual Time of Diagnosis

right after the onset of symptoms, not immediate

Stage of Recovery, Disability or Death

the final stage of the disease process

Health Approaches: Clinical Health Approach

individual health issues and treating the individual person

Public Health Approach

public health from a statistical or government standpoint, reduce "overall" exposure

Bradford-Hill Criteria

a set of criteria that are used to establish cause-and-effect relationships based on observational studies (that is, the criteria used when randomized experiments are not feasible or ethical)

Casual Relationship

correlation to casualties

Strength of Association

the relationship is clear and the risk estimate is high

Consistency

observation of association must be repeatable in different populations at different times, must be a consistent correlation across all groups

Specificity

a single cause produces a single effect

Alternate Explanations

considering of multiple hypotheses before making conclusions about whether an association is causal or not

Temporality

cause/exposure must precede the effect or outcome

Dose-Response Relationship

an increasing amount of exposure increases the risk

Biological Plausibility

the association agrees with currently accepted understanding of biological and pathological processes, it makes sense

Experimental Evidence

the condition can be altered, either prevented or accelerated, by an appropriate experimental process, keep in mind current technology around the disease

Coherence

the association should be compatible with existing theory and knowledge, including knowledge of past cases and epidemiological studies

Epi-Curve

a graph with date (x-axis) and a number of cases (y-axis) for a certain outbreak of a disease

Point Source Epi-Curve

the shape of the curve commonly rises rapidly and contains a definite peak and then a gradual decline

Continuous Common Source Epi-Curve

Occur when the exposure to the sources is prolonged over an extended time period of time and may occur over more than one incubation period. The downslope is usually a sharp decline

Propagated Epi-Curve

When a case of disease serves as a later source of for subsequent cases

Line List

an organized, detailed list of each record entered

Cluster Maps

a diagram using bubbles to map out an idea

Subdivided Tables

a graphic that has subjects tethered to the main square (similar to a cluster map)

Chain of Transmission

a cluster map that shows the progression of an epidemic or outbreak

Experimental Epidemiology

a type of epidemiology where the medical professional alters a case and then proceeds to observe

Randomized Controlled Trial

typically used for a new medicine or drug testing in a closed, secure environment

Field Trial

conducted in an environment that includes those at high risk of contracting a disease

Community Trial

research is conducted on an entire community or neighborhood

Observational Epidemiology

a type of epidemiology where the medical professional does not alter a case and simply observes

Classical Epidemiology

population oriented, studies community origins of a health problem related to nutrition, environment, human behavior, and the psychological, social, and spiritual state of a population

Clinical Epidemiology

studies patients in health care settings in order to improve the diagnosis and treatment of various diseases and the prognosis for patients already affected by a disease

Infectious Disease Epidemiology

heavily dependent on laboratory support

Chronic Disease Epidemiology

heavily dependent on complex sampling and statistical methods

Analytical Epidemiology

concerned with the search for causes and effects, or the why and the how. Epidemiologists use analytic epidemiology to quantify the association between exposures and outcomes and to test hypotheses about causal relationships

Frequency

the number of cases in a specific region and the relationship to the size of the population (the rate allows epidemiologists to compare disease occurrence across different populations)

Pattern

refers to the occurrence of events by time, place, and person in a particular period of time (ex: a disease occurs only in a specific environment like schools, or with people with certain characteristics)

Outbreak

More cases of a particular disease than expected in a given area or among a specialized group of people over a particular time

Epidemic

large numbers of people infected over a wide geographical area

Pandemic

an epidemic that is occurring over several countries or continents and effecting a large proportion of the populations

Surveillance

the systematic and ongoing collection, analysis, interpretations, and dissemination of health data

Plague

a serious potentially life-threatening infectious disease that is usually transmitted to humans by rodent fleas

Majo Forms of Plague

Bubonic, Septicemic, and Pneumonic

Vector

an animal that transmits disease

Fomite

a physical object that serves to transmit disease from person to person

Diagnosis

the identification of the nature of illness by examination of the symptoms

Prognosis

the likely course of a disease or ailment

Latency Period

between exposure and infection, without any clinical symptoms (similar to the incubation period, between exposure and clinical symptoms)

Infectivity

capacity to cause infection in a susceptible host

Pathogenicity

capacity to cause disease in a host

Virulence

the severity of disease that the agent causes to a host

Mortality Rate

the measure of the number of deaths per population in a given time period

Morbidity

the condition of being diseased

Virus

an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host

Fungi

any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as mushrooms

Protozoa

single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris

Natality

the ratio of the number of births to the size of the population (birth rate)

Herd Immunity

the resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, especially through vaccination

Prevalence

the proportion of a particular population found to be affected by a medical condition

Cluster

an aggregation of cases of a disease or another health-related condition, such as a cancer or birth defect, closely grouped in time and place

Antigens

a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies

Antibodies

a blood protein produced in response to and counteracting a specific antigen

Prion

the infectious agent responsible for several neurodegenerative diseases found in mammals. It causes Antitoxin, an antibody to a microbial toxin. An antitoxin binds specifically with the toxin, neutralizing it

Creutzfeldt-Jakob Disease

a chronic, progressive, fatal disease of the central nervous system caused by a prion

Arenavirus

a type of RNA virus (cause of Lassa virus)

Bactericide

an agent that kills bacteria

Biologic Transmission

disease transmission in which an infectious organism undergoes some morphologic or physiologic change during its passage through the vector

Carrier

an infected individual who is a potential source of infection for other people

Acquired Immunity

specific immunity that develops after exposure to a particular antigen or after antibodies are transferred from one individual to another (used in vaccines)

Fungicide

an agent that kills fungi

Intermediate Host

a host that serves as a temporary but essential environment for the completion of a parasite's life cycle

Pathogen

a disease producing agent

Superinfection

a bacterial or fungal infection that is resistant to the drug(s) being used to treat it

Toxin

microbial product or component that at low concentrations can injure a cell or organism

Sporadic

a disease that occurs infrequently and irregularly

Distribution

the spread of who, when, and where

Determinants

Agents, causes, risk factors, and sources

Cross-Sectional Study

uses different groups of people who differ in the variable of interest but who share other characteristics such as socioeconomic status, educational background, and ethnicity

Cohort Study

peer review and learning process from an observational, separated standpoint looking back onto the past

Advantages of Cohort Study

subjects in cohorts can be matched, which limits the influence of confounding variables - standardization of criteria/outcome is possible - easier and cheaper than a randomized controlled trial (RCT)

Case-Control Study

a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute

Disadvantages of Cohort Study

cohorts can be difficult to identify due to confounding variables - no randomization, which means that imbalances in patient characteristics could exist - blinding/masking is difficult - an outcome of interest could take time to occur

Advantages of Case-Control Study

good for studying rare conditions or diseases - less time needed to conduct the study because the condition or disease has already occurred - lets you simultaneously look at multiple risk factors - useful as initial studies to establish an association - can answer questions that could not be answered through other study designs

Disadvantages of Case-Control Study

retrospective studies have more problems with data quality because they rely on memory and people with a condition will be more motivated to recall risk factors (also called recall bias) - not good for evaluating diagnostic tests because it's already clear that the cases have the condition and the controls do not - it can be difficult to find a suitable control group

Observational Study

attempt to understand cause-and-effect relationships from afar

Etiology

the study of the physiologic cause of a disease

Longitudinal Study (or longitudinal survey, or panel study)

a research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time (i.e., uses longitudinal data). It is often a type of observational study, although they can also be structured as longitudinal randomized experiments

Ecological Study

studies of risk-modifying factors on health or other outcomes based on populations defined either geographically or temporally

Host Factors

genetic susceptibility, resiliency, nutritional status, immune system

Agent Factors

infectivity of a pathogen, addictive qualities of a substance of abuse

Environmental Factors

sanitary conditions, social context, availability of healthcare

Time

when the outbreak takes place, considering current conditions

Place

the physical location of the epidemic situation

Person

the individual needs and conditions of the people infected