Disease and Epidemiology Flashcards

Flashcards covering key vocabulary and concepts from the Disease and Epidemiology lecture notes.

Epidemiology

The study of the geographical distribution and timing of infectious disease occurrences and how they are transmitted and maintained in nature, with the goal of recognizing and controlling outbreaks.

Etiology

The study of the causes of disease.

Etiologic agent/Causative agent

The agent/source of the disease.

Morbidity

The state of being diseased; can be expressed as the number of individuals without reference to the size of the population.

Morbidity Rate

The state of being diseased expressed as a percent of the population.

Prevalence

The number, or proportion, of individuals with a particular illness in a given population at a point in time.

Incidence

The number or proportion of NEW cases in a period of time.

Mortality

The incidence and prevalence of death; may be expressed as a percentage of the population that has died from a disease or as the number of deaths per 100,000 persons (or another number).

Sporadic diseases

Diseases that are seen only occasionally, and usually without geographic concentration.

Endemic diseases

Diseases that are constantly present (often at a low level) in a population within a geographic region.

Epidemic diseases

Diseases for which a larger number of cases occurs in a short time within a geographic region; signals the breakdown of an equilibrium in disease frequency.

Pandemic disease

An epidemic that happens on a worldwide scale – multiple countries or continents.

Centers for Disease Control and Prevention (CDC)

The main national public health agency of the U.S., charged with protecting the nation from disease and injury.

National Notifiable Disease Surveillance System (NNDSS)

Works with regional, state, and territorial public health departments to monitor diseases important to public health on a national scale.

Notifiable diseases/Reportable diseases

Diseases considered important to public health on a national scale that must be reported to the CDC when encountered.

Morbidity and Mortality Weekly Report (MMWR)

A weekly report, published by the CDC, that provides information regarding public health issues and the latest data pertaining to notifiable diseases to physicians and health-care workers.

World Health Organization (WHO)

The main international public health agency; part of the United Nations (UN); monitor and report infectious diseases and develop and implement prevention strategies.

John Snow

British physician, father of epidemiology, determined the etiologic agent of a cholera outbreak by tracing the outbreak back to a water pump using a “ghost map.”

Common source spread

A single source that infects all affected persons in an outbreak; often leads to large-scale but localized outbreaks of short duration.

Point source spread

A common source that operates for a short period of time.

Continuous common source spread

A common source which occurs for a longer period of time (longer than the incubation period).

Intermittent common source spread

A common source which occurs for a period, then stops, then begins again.

Propagated spread

Occurs through direct or indirect person-to-person contact; no single source for infection; each infected person becomes a source for subsequent infections.

Florence Nightingale

Nurse during the Crimean War; her record keeping demonstrated that most soldier deaths were a result of preventable infectious diseases due to poor sanitation and lack of access to hospital facilities.

Joseph Lister

Provided early epidemiological evidence leading to good public health practices in clinics and hospitals, including hand washing, instrument cleaning, and disinfection protocols.

Robert Koch

Established the Koch postulates, determining the causative agent of a particular disease to a particular microbe; established that B. anthracis causes anthrax.

Observational study

Studies where researchers observe the effect of a risk factor, diagnostic test, treatment or other intervention without trying to change who is or isn't exposed to it.

Retrospective studies

Gather data from the past on present-day cases. Data may include medical history, age, gender. Examines association between factors chosen or available to researchers.

Prospective studies

Follow individuals and monitor their disease state during the course of the study.may look for associations between disease state and variables that were measured

Experimental study

Use of laboratory or clinical studies in which a variable is manipulated on study subjects to study the connections between diseases and potential causative agents or to assess treatments.

Reservoir

Organisms or nonliving sites where a pathogen can reside.

Carrier

An individual or animal capable of transmitting a pathogen.

Passive carrier

Contaminated with the pathogen and can mechanically transmit it to another host but is infected itself.

Active carrier

Is infected by the pathogen, may or may not show symptoms, and is capable of transmitting the infection.

Asymptomatic carrier

An active carrier that does not show symptoms and is capable of transmitting the disease.

Zoonoses

A pathogen that may have more than one living reservoir; animal acts as reservoirs of human disease and transmit the pathogen to humans.

Definitive host

The preferred host of a parasite and where the parasite reaches sexual maturity.

Intermediate host

The host where the parasite goes through several immature life cycle stages or reproduces asexually.

Direct contact transmission

Person-to-person transmission via touching, kissing, sexual intercourse, or droplet sprays.

Vertical direct contact

Transmission of pathogens from mother to child during pregnancy, birth, or breastfeeding.

Horizontal direct contact

Mucous membrane contact or in some cases skin to skin contact; sexual activity.

Droplet transmission

When a person coughs or sneezes, small droplets which may contain pathogens are ejected, and may be transferred to a host within one meter.

Airborne transmission

Transmission over distances greater than one meter.

Indirect contact

Transmission using fomites which become contaminated by pathogens from an infected individual or reservoir.

Fomites

Nonliving objects that facilitate the indirect transmission of pathogens, like doorknobs, towel etc.

Vehicle transmission

The transmission of pathogens through vehicles such as water, food, and air; often caused by poor sanitation.

Vector transmission

Disease transmitted via an animal (often an arthropod) that carries disease from one host to another.

Mechanical transmission

Uses a mechanical vector, carried on the outside of the animal without causing infection to the vector. (Fly that lands in feces then on person or food)

Biological transmission

Uses a biological vector, carried inside the animal; the vector is infected with the pathogen.

Emerging infectious disease

New to the human population or has shown an increase in prevalence in the previous twenty years.

Reemerging infectious disease

Disease that is increasing in frequency after a period of decline.

Contact transmission

Transmitted via physical contact, direct or indirect

Girolamo Fracastoro

First to propose germ theory of disease