Principles of Disease and Epidemiology

Vocabulary flashcards generated from the Principles of Disease and Epidemiology lecture notes.

Disease

An abnormal state in which the body is not functioning normally.

Infection

Colonization of the body by pathogens.

Pathology

The study of disease.

Pathogenesis

The development of disease.

Etiology

The study of the cause of a disease.

Epidemiology

The study of the distribution and causes of disease in populations.

Normal microbiota

Microorganisms that permanently colonize the host without causing disease under normal conditions.

Transient microbiota

Microorganisms that may be present on or in the host for days, weeks, or months.

Dysbiosis

A microbiota imbalance associated with disease.

Microbial antagonism

Competition between microbes that protects the host by occupying niches pathogens might occupy, producing acids, and producing bacteriocins.

Biome

A reasonably well defined habitat which has distinct bio-physio-chemical properties.

Microbiome

The combination of microbiota and its "theatre of activity", including microbial structural elements, mobile genetic elements, and microbial metabolites.

Communicable disease

A disease that can spread from one host to another.

Contagious disease

A disease that is easily spread from one host to another.

Noncommunicable disease

A disease that is not transmitted from one host to another, arising most often from an individual's normal microbiota or the environment.

Subclinical disease

A disease that has no noticeable signs or symptoms.

Symptom

A change in body function that is felt by a patient as a result of disease.

Sign

A change in a body that can be measured or observed as a result of disease.

Syndrome

A specific group of signs and symptoms that accompany a disease.

Incubation period

The stage of disease between initial infection and the appearance of signs or symptoms.

Prodromal period

The stage of disease characterized by mild signs or symptoms following the incubation period.

Period of illness

The stage of disease when signs and symptoms are most severe.

Period of decline

The stage of disease during which the signs and symptoms subside.

Period of convalescence

The stage of disease recovery during which the host regains strength and returns to health.

Acute illness

A short-term illness because the pathogen is eliminated by host defenses, typically leaving the person immune to reinfection.

Chronic illness

An illness that persists over a long time period.

Latent illness

An illness that may recur after a period of latency if immunity weakens.

Pathogenicity

The ability to cause disease by overcoming the defenses of a host.

Virulence

The extent of pathogenicity of a microorganism.

Primary pathogen

A pathogen that causes disease in an otherwise healthy individual.

Opportunistic pathogen

A pathogen that only causes disease in compromised tissues.

Reservoirs of infection

Continual sources of infection, which can be human, animal, or nonliving.

Carrier

An individual who may have unapparent infections or latent diseases and can transmit the pathogen.

Zoonosis

A disease that occurs primarily in wild and domestic animals but can be transmitted to humans.

Direct contact transmission

Transmission requiring close association between an infected host and a susceptible host.

Indirect contact transmission

Transmission spread by nonliving objects called fomites.

Fomite

A nonliving object involved in the indirect transmission of pathogens.

Droplet transmission

Transmission via airborne droplets over short distances.

Vertical transmission

Disease transmission from mother to fetus or infant.

Horizontal transmission

Disease transmission from person to person via direct or indirect contact.

Vehicle transmission

Transmission of a pathogen by an inanimate reservoir such as food, water, or air.

Vector

An arthropod (such as a flea, tick, or mosquito) that transmits a pathogen.

Mechanical transmission

Vector transmission in which an arthropod carries a pathogen on its feet.

Biological transmission

Vector transmission in which a pathogen reproduces inside the vector.

Healthcare-Associated Infections (HAIs)

Infections acquired while receiving treatment in a healthcare setting such as a hospital, therapy center, urgent care facility, or long-term care residence.

Parenteral route

A portal of entry where pathogens enter the body directly through breaches in skin and mucous membranes, such as punctures or cuts.

Localized infection

An infection restricted to a specific part of the body.

Systemic infection

An infection disseminated throughout the body.

Sepsis

Systemic inflammation due to infection.

Bacteremia

The presence of bacteria in the blood.

Toxemia

The presence of toxins in the blood.

Viremia

The presence of viruses in the blood.

$$ID_{50}$$

Infectious dose for $50\%$ of the test population.

$$LD_{50}$$

Lethal dose (of a toxin) for $50\%$ of the test population.

Attack rate

The percentage of people who become ill in a population after exposure to an infective agent.

Incidence

Fraction of a population that contracts a disease during a specific time.

Prevalence

Fraction of a population having a specific disease at a given time.

Sporadic disease

A disease that occurs occasionally in a population.

Endemic disease

A disease constantly present in a population.

Epidemic disease

A disease acquired by many hosts in a given area in a short time.

Pandemic disease

A worldwide epidemic.

Morbidity

Incidence of disease in a population.

Mortality

Overall death rate in a population.

Case-fatality rate

Percentage of a population that dies from a specific disease.

Chain of Infection

A sequence of steps through which infectious diseases spread, including a reservoir, portal of exit, transmission, portal of entry, and susceptible host.

Case-control study

An analytical epidemiological study that compares individuals with a disease (cases) to individuals without the disease to identify risk factors.

Cohort study

An analytical epidemiological study that examines individuals with known risk factors to observe disease development over time.

Cross-sectional study

An analytical epidemiological study that evaluates disease status and risk factors simultaneously at a single point in time.

Centers for Disease Control and Prevention (CDC)

An organization that provides support for labs in the U.S. and abroad, collects data on over 50 notifiable diseases, and publishes the Morbidity and Mortality Weekly Report (MMWR).

World Health Organization (WHO)

A global organization with 193 member states that sets international standards for health, provides health education, and coordinates responses to epidemics.