Disease Detectives Vocab

Common Vocab

Endemic

Constant presence and/or usual prevalence of a disease in a population within a geographic area

Pathogenicity

Proportion (or likelihood) of infected ppl who develop clinical disease

Iatrogenic

Disease caused by medical treatment

Host

A person or organism that can be infected by an agent

Isolation

Limiting movement of people who are ill with a contagious disease

Quarantine

Limiting movement of people who are presumed to have been exposed with a contagious disease

Determinant

Brings about change in a health condition or in other specified characteristic (risk factor)

Etiologic

Relating to the cause or manner of causation of a disease

Antigenic Drift

Minor changes happening within a virus; gradual accumulation of mutations during circulation of virus as a consequence of the high error rate of RNA-dependent RNA polymerase and the selective pressure of immune responses or antivirals

Vector

Any living agent that carries and transmits an infectious pathogen

Vehicle

Inanimate intermediary that can carry and spread disease (food, water, air, and biologic products like blood)

CDC Director

Mandy K Cohen

Efficacy

The ability to produce results under ideal conditions

Efficiency

The ability to produce results with minimal resources

Effectiveness

The ability to produce results in the field

Convalescent Carrier

Recovered from illness but still capable of spreading disease

Incubatory Carrier

Transmit the disease during the incubation pd

Chronic Carrier

Continue to harbor the disease for months/yrs after initial infection

Descriptive Triad:

Person, place, time

Transmission Triad (epidemiological triad)

Agent, Susceptible Host, Environment

Agent

A microbial organism with the ability to cause disease

Incubation Period

Time between exposure and onset of symptoms for infectious diseases

Latency Period

The time from exposure to a causal agent to onset of symptoms of a noninfectious/chronic disease

Outbreak

Sudden inc in cases above normal expectancy w/in a limited geographic area over short pd of time

Epidemic

A greater number of cases than expected (outbreak) over a wide geographical area

Pandemic

An epidemic spread over several countries and continents

Cluster

An aggregation of cases grouped by time/place

Fomite

Inanimate object or surface that can carry and transmit infectious agents

Epizootic

An outbreak of disease among animals

Nosocomial Infection

Infection from a medical setting

Fulminant

Severe onset of disease

External Validity

Ability to generalize results to a population outside the sample

Internal Validity

Ability to attribute an intervention as the cause of the result

Hyperendemic

Persistent high levels of disease among all age groups

Hypoendemic

Persistent low levels of diseases

Holoendemic

Persistent high levels of disease beginning in early life

Control VS Elimination VS Eradication VS Extinction

Control - reduction of disease incidence, prevalence, morbidity or mortality to a locally acceptable/manageable level as a result of deliberate efforts

Eradication - Permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts

Elimination - Reduction to zero of the incidence of a disease in a defined geographical area as a result of deliberate efforts

Extinction - The specific agent no longer exists in nature or the laboratory

Spillover Case

First case where human contracts disease from animal

Recall Bias

Participants in a research study or clinical trial do not accurately remember a past event or leave out details

Survivor Treatment Bias

Patients who live longer are often more likely to receive treatment than patients who die early

Proficiency Bias

Mistakes were made, interventions are not applied equally because of differences in skill/training

Hawthorne Effect

Subjects change or improve their behavior because it is being evaluated or studied

Follow-up/Withdrawal Bias

Subjects who leave the study (drop-outs) differ significantly from those that remain

Observer Bias

Researcher's expectations, opinions, or prejudices influence what they perceive or record in a study

Case Definition

Time, place, person, clinical criteria

Cohort Study

Separate by exposed or not-exposed, see if they develop disease of interest; RISK RATIO

Case-Control Study

Separate by disease status, check their exposures; good for rare diseases, ODDS RATIO

Diseases Eradicated

Smallpox, Rinderpest

Idiopathic

A disease with an uncertain origin

R(0) — Basic Reproductivity Number

Average number of secondary cases from a primary case (contagiousness); influenced by contagiousness of micro-organism and # of susceptible ppl in the pop in contact

Eradication

Permanent reduction to zero of the worldwide incidence of infection

Attrition Bias

Unequal loss of participants throughout study

Contact Tracing

Identifying individuals who have been in the proximity of a infected person, to isolate/test/treat them

Mesoendemic

An endemic disease w/ a moderate rate of infection

John Snow

Father for epidemiology, used descriptive epidemiology to solve a cluster of Cholera in London (Broad Street pump)

Louis Pasteur

Vaccines for rabies & anthrax, confirmed germ theory, disproved theory of spontaneous generation, pasteurization

Joseph Lister

Promoted idea of sterile surgery, antiseptics

Florence Nightingale

Founder of modern nursing, established nursing school @ St. Thomas Hospital

Reverse Zoonosis/anthroponosis

A disease (pathogen) that can be spread from humans to non-humans (animals)

Arbovirus

Viruses transmitted between hosts by mosquitos, ticks, and other arthropods

Prophylaxsis

An action taken to prevent disease

Brian MacMahon

Published the first epidemiologic text w/ a systematic focus on study design

Public Health Surveillance

The ongoing, systematic collection, analysis, and interpretation of health-related data essential to planning, implementation, and evaluation of public health practice

Descriptive Epidemiology

identifying the time, place, and the person involved in the onset of the health-related event.

Analytic Epidemiology

concerned with finding the causes of the health-related event (through studies) and to identify the interventions of the health problem.

Sporadic

a disease that occurs infrequently and irregularly

Risk

The probability that an event will occur

Benefit & Disadvantage of Cohort

Benefits: clear temporal sequence, can study multiple outcomes from one exposure

Disadvantage: expensive, not good for rare diseases

Benefit & Disadvantage of Case-Control

Benefits:

Herd Immunity

If a high enough prop. of the pop is resistant to an agent, then those who are susceptible will be protected by the resistant majority

Berkson’s Bias

Selection bias whereby hospital controls are used in a case-control study

Neyman’s Bias (Prevalence-Incidence Bias)

Selection bias whereby individuals with severe or mild disease (e.g. death) are excluded

Pygmalion Effect

Where someone's high expectations improves a person’s behavior and therefore their performance in a given area

Eradicated Diseases

1st Smallpox – 1980, 2nd Rinderpest

Current CDC Director

Susan Monarez

Infectivity

The proportion (or likelihood) of people exposed who become infected with the disease

Virulence

The proportion (or likelihood) of infected individuals developing severe disease or death

Prevalence

proportion of persons in a pop who have a particular disease/attribute at a given time, regardless of when they first developed the disease

Incidence

the number of new cases that develop in a given pd of time

Zoonotic

A disease or infection transmitted from animals to humans

Antigenic shift

A sudden, major change in the genetic makeup; when two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens

Aseptic Technique

Used to prevent contamination by pathogens during medical procedures (e.g. sterile gloves, washing hands)

Synergistic Effect

When two or more entities are combined, their overall effect is greater than the sum of their individual effects

Viral Tropism

The capability of an infectious virus to infect particular cells (cellular tropism), tissue (tissue tropism) or host species (host tropism)

Biological Transmission

When the pathogen reproduces within the vector and is then transmitted to the new host

Effect Modification

Occurs when the effect of an exposure on an outcome differs depending on the level of a third variable.

Confounding

When an extraneous variable influences both the exposure and the outcome, leading to a distorted association

Surveillance

The close and continuous observation of one or more persons for the purpose of direction, supervision, or control

Lead-Time Bias

Early detection looks like increase in survival; common with improved screening

Koch’s Postulates

criteria to establish a causal relationship btw a causative microbe and disease

Prodrome / (Prodromal Stage of Illness)

An early sign or symptom that often indicates the onset of a disease before more diagnostically significant signs or symptoms

Steps of Surveillance

1. Data Collection

2. Data Analysis

3. Data Interpretation

4. Data Dissemination

5. Link to Action (optional)

Natural History of Disease

The progression of a disease in an individual from exposure to resolution

Framingham Heart Study

Cardiovascular cohort study of residents of the city of Framingham, established risk factors to coronary heart disease

Ecological Fallacy

Occurs when an inference about a group (or population) is incorrectly applied to individuals within that group; i.e. the assumption that because a trait is present in a group as a whole, it must also be present in each individual within that group.

Validity

The ability of the results to represent what they’re supposed to measure

Reliability

The reproducibility of the same results

Undercoverage Bias

Selection bias when a part of the population is excluded from your sample (selection bias)

Volunteer Bias

(Self-selection Bias); participants choose whether they want to be a part of the sample or not

Non-response bias

some selected sample members being unable or unwilling to participate