Chapter 14 Principles of Disease and Epidemiology

Flashcards covering key vocabulary and concepts from a lecture on the principles of disease and epidemiology.

Pathology

Scientific study of disease, including etiology, pathogenesis, and changes caused by the disease.

Etiology

The cause of a disease.

Pathogenesis

The manner in which a disease develops.

Infection

Invasion or colonization of the body by pathogenic microorganisms.

Disease

Occurs when an infection causes a change from the normal state of health.

Normal Microbiota (Flora)

Microorganisms that colonize the body but do not produce disease under normal circumstances.

Microbial Antagonism

The competition between normal microbiota and potential pathogens.

Bacteriocins

Proteins produced by bacteria that inhibit other bacteria of similar species.

Probiotics

Live microbes applied to or ingested into the body, intended to exert a beneficial effect.

Symbiosis

The host and microbiota living together.

Commensalism

One organism benefits, and the other is neither harmed nor helped.

Mutualism

Both organisms benefit.

Parasitism

One organism benefits at the expense of the other (the host).

Opportunistic Pathogens

Organisms which do not normally cause disease in a healthy person but will cause disease if the person is weakened.

Koch's Postulates

A set of postulates used to prove the cause of an infectious disease.

Symptoms

Subjective changes in body function (e.g., pain, malaise).

Signs

Objective changes that can be observed and measured (e.g., lesions, fever).

Syndrome

A group of signs and symptoms that may always accompany a particular disease.

Communicable Disease

Disease that spreads from one host to another, either directly or indirectly.

Contagious Disease

Disease that spreads easily from person to person.

Noncommunicable Disease

Disease that is not spread from host to host.

Incidence

The fraction of a population that contracts a disease during a particular time period.

Prevalence

The fraction of a population having a disease at a specified time.

Sporadic (Disease)

Occurs only occasionally.

Endemic (Disease)

Constantly present in a population.

Epidemic (Disease)

Many people in a given area acquire a certain disease in a relatively short time period.

Pandemic (Disease)

A worldwide epidemic.

Acute (Disease)

Develops rapidly but lasts only a short time.

Chronic (Disease)

Develops more slowly and is often less severe but can be continual or recurrent.

Latent (Disease)

Inactive for a time.

Emerging Infectious Diseases

New or changing diseases showing an increased incidence in the recent past or a potential to increase in the near future.

Local Infection

Limited to a relatively small portion of the body.

Systemic (Generalized) Infection

Spread throughout the body.

Bacteremia

Presence of bacteria in the blood.

Septicemia

Bacteria multiply in the blood.

Toxemia

Presence of toxins in the blood.

Viremia

Viruses in the blood.

Primary Infection

An acute infection that causes the initial illness.

Secondary Infection

An opportunistic pathogen taking advantage of weakened defenses due to a primary infection.

Reservoir (of Infection)

Source of infection, can be living or non-living.

Carriers

Transmit from person to person; some may not exhibit symptoms.

Zoonoses

Diseases transmitted to humans from animals.

Contact Transmission

Spread of disease by direct or indirect contact, or by droplet transmission.

Indirect Contact (Transmission)

Spread to a susceptible host through a non-living object.

Fomite

A non-living object involved in indirect contact transmission.

Droplet Transmission

Mucus droplets spread a short distance (less than one meter).

Vehicle Transmission

Transmission of disease agents by a medium such as food, water, or air (more than 1 meter).

Vector Transmission

Animals which carry pathogens from one host to another.

Nosocomial Infections

Infections acquired as a result of a hospital stay.

Incubation Period

Time between infection and appearance of symptoms or signs.

Prodromal Period

Short period of mild symptoms in some diseases.

Period of Illness

Exhibits overt signs and symptoms; most acute stage of disease.

Period of Decline

Signs and symptoms diminish, susceptible to secondary infections.

Period of Convalescence

Regains strength and returns to prediseased state.

Epidemiology

Study of when and where diseases occur and how they are transmitted in populations.

Descriptive Epidemiology

Collection of data that describe the occurrence of the disease under study.

Analytical Epidemiology

Analyzes a particular disease to determine its probable cause (risk factors, etc.).

Experimental Epidemiology

Makes hypothesis about a particular disease and experiments to test this hypothesis with a group of people.

Case Reporting

Requires reporting of certain disease cases to the state and national level.

Centers for Disease Control and Prevention (CDC)

Central source of epidemiological information in the U.S.

Morbidity

Incidence of specific notifiable diseases.

Mortality

Number of deaths from these diseases.