Science Olympiad Disease Detectives Vocab

Incubation period

The stage of subclinical disease (from the time of exposure to onset of disease symptoms) in infectious diseases

Latency period

The stage of subclinical disease (from the time of exposure to onset of disease symptoms) in chronic diseases.

Spectrum of disease

The range of signs and symptoms associated with a particular disease, which can vary in severity and presentation.

Infectivity

The proportion of exposed people who become infected.

Pathogenicity

The proportion of infected people who develop clinically apparent disease or the property of causing disease after infection

Virulence

The proportion of clinically apparent cases that are severe or fatal.

 Carrier

People who are infectious but have subclinical disease; a person or animal that doesn’t show apparent disease who has a specific infectious agent and is able to give the agent to others. 

Prion

An infectious protein that are transmitted either by inheritance or by eating or receiving contaminated food; they are a type of infectious pathogen that doesn’t contain a nucleus or RNA.

Outbreak

A localized epidemic; more cases of a specific disease than expected in a given area or among a certain group of ppl over a specific time period

Epidemic

Large numbers of people over a wide geographic area (such as over one region/area of one continent) are affected

Pandemic

An epidemic occurring over an extremely wide area (many countries or continents) & often affecting a large part of the population.

From smallest to largest, what are the categories of disease occurrence/levels of disease?

Endemic, epidemic, and pandemic.

Cluster

An aggregation of cases over a specific period (especially cancer & birth defects) closely grouped in time & space regardless of whether the number is more than the expected number (often the expected number of cases is unknown).

Sporadic

A disease that occurs infrequently and irregularly.

Zoonosis

An infectious disease that can be given from animals to humans.

Holoendemic

A disease that basically the entire population has, but mainly among an entity that carries or transmits an infectious pathogen (like a parasite).

Active Immunity

When one is exposed to a live pathogen, develops the disease, and becomes immune because of the primary immune response.

Active Immunity gained through Infection

Catching the disease firsthand and gaining resistance to it.

Active immunity gained through vaccination

The body is given an inactive form of the disease.

Passive immunity

Immunity gained from the infection of antibodies that aren’t naturally made by the recipient’s cells.

Maternal passive immunity

Antibodies are passed through the placenta either during or before childbirth.

Artificial passive immunity

Monoclonal antibodies are injected into the bloodstream through an IV tube

Innate immunity

The body’s natural nonspecific defense system that’s present from birth.

Fulminant

A sudden or severe effect.

Chain of Infection

A process that begins when an agent leaves its reservoir or host through a portal of exit, and is moved by some mode of transmission, then enters through an appropriate portal of entry to infect a susceptible host.

Prevalence

The proportion of individuals in a population who have a specific disease or condition at a particular point in time or within a specified period.

Risk

The chance that someone will be affected by, or die from, an illness or injury within a stated time or age span.

Secular Trend

A long term change in morbidity/mortality occurring over many years or decades.

Rate

Number of cases during a specific period

Incidence

The number of new cases of a disease occurring in a population over a specified period.

Airborne transmission

Transmission that occurs via droplets (usually mucous droplets) where droplets are liquids that remain airborne whether as aerosols (very small droplets) or associated with dust particles.

Person-time

Almost anything an infected person or reservoir can touch, upon which can be left a residue of contagious pathogens.

Fomite

A physical object (usually solid) that transmits an infectious agent from person to person.

Droplet Transmission

The consequence of being coughed, sneezed, or spit on. Mucous droplets must still be moving with the speed imparted upon it leaving the mouth.

Portal of Entry

An opening allowing the microorganism to enter the host; the route a pathogen takes to enter a host.

Nosocomal Disease

An infection that is acquired in a hospital.

Asymptomatic

Shows no signs or symptoms but is infected and can carry the disease.

Vector

Any living agent (like an animal) that carries or transmits an infectious pathogen (like a parasite).

Vehicle

A nonliving object that transmits disease (which includes biological products like blood, food, water, and etc.)

Herd Immunity

The minimum percentage of people within a community who need to be immune to a disease to prevent an outbreak.

R₀/(R-nought)

The average number of people one infected person will spread the infection to during the course of the disease.

Index Case

The first patient in an epidemiological study.

Case

A countable instance in the population or study group of a specific disease, health disorder, or condition under investigation; sometimes a person with the specific disease

Confidence Interval

A range of values for a variable of interest, like rate, constructed so that this range has a specified probability of including the true value of the variable.

Confidence level

The specified probability of a confidence interval.

Confidence limits

The end points of the confidence interval.

Crude mortality rate

The mortality rate from all causes of death for a population.

Direct transmission

The immediate transfer of an agent from a reservoir to a susceptible host by direct contact or droplet spread.

Epidemiology triad

The traditional model of an infectious disease causation that includes 3 parts: an external agent, a susceptible host, and an environment that brings the host & agent together, so that disease occurs.

Exposed

A group whose members have been exposed to a supposed cause of disease or health state of interest, or has a characteristic that’s a determinant of the health outcome of interest.

Indirect Transmission

The transmission of an agent carried from a reservoir to a susceptible host by suspended air particles or by animate (vector) or inanimate (vehicle) intermediaries.

Measure of Association

A quantified relationship between exposed and disease.

What are some examples of a Measure of Association?

Relative Risk, Rate Ratio, and Odds Ratio

Morbidity

Rate of disease in a population.

Mortality rate

A measure of the frequency of occurrence of death in a defined population during a specific interval of time.

Reservoir

The habitat in which an infectious agent usually lives, grows and multiplies; can include human reservoirs, animal reservoirs, and environmental reservoirs.

Risk factor

A part of personal behavior or lifestyle, an environmental exposure, or an inborn or inherited characteristic that’s associated with an increased occurrence of disease or other health-related event or condition.

Seasonality

Change in physiological status or in disease occurrence that conforms to a regular seasonal pattern.

Sensitivity

The ability of a system to detect epidemics and other changes in disease occurrence; the proportion of people with disease who are correctly identified by a screening test or case defined as having disease.

Specificity

The property of people without disease who are correctly identified by a screening test or case defined as not having disease.

Validity

The degree to which a measure actually measures or detects what it’s supposed to measure.

Variance

A measure of the dispersion shown by a set of observations.

Surveillance

Gain knowledge of disease patterns, injury, or other health problems for prevention and control.

Confounding

When the effects of 2 risk factors are mixed in the occurrence of the health-related event under study; when an extraneous factor is related to both disease and exposure.

Confounding variable

A variable that can cause the disease being studied and is also associated with the exposure.

Epi(demic) curve

A histogram showing the course of the disease or outbreak to find the source of the expsoure.