Modes of Disease Transmission
Case Concepts in Epidemiology
Epidemics, Endemics, and Pandemics
Levels of Prevention
Carriers
100

The direct and immediate transfer of an agent from a host/reservoir to a susceptible host.

What is Direct Transmission?

100

The first disease case in the population.

What is Primary Case?

100

An epidemic affecting or attacking the population of an extensive region, country, or continent.

What is Pandemic?

100

Effort to prevent a disease or disorder before it happens.

What is Primary Prevention?

100

An individual who has been exposed to and harbors a disease-causing organism (pathogen) and who has done so for some time, even though he or she may have recovered from the disease.

What is Active Carrier?

200

Disease that results when an agent is transferred or carried by some intermediate item, organism, means, or process to a susceptible host.

What is Indirect Transmission?

200

The first disease case brought to the attention of the epidemiologist.

What is Index Case?

200

When an increase in the number of cases of disease occurs above what is normally expected for a given time and place.

What is Epidemic?

200

Behavior change on the part of the individual that prevents a disease or disorder before it happens (e.g., exercising, not smoking, reducing dietary fat intake).

What is Active Primary Prevention?

200

Individual who harbors a pathogen and who, although in the recovery phase of the course of the disease, is still infectious.

What is Convalescent Carrier?

300

Transfer of bacteria or viruses on dust particles or on small respiratory droplets that may become aerosolized when individuals sneeze, cough, laugh, or exhale. Transmission allows organisms that are capable of surviving for long periods outside the body and that are resistant to drying to enter the upper and lower respiratory tract. Diseases capable of this type of transmission include influenza, polio, whooping cough, pneumonia, and tuberculosis.

What is Airborne Transmission?

300

A person who becomes infected from contact with the primary case after the disease has been introduced into the population.

What is Secondary Case?

300

The ongoing, usual, or constant presence of a disease in a community or among a group of people.

What is Endemic?

300

Does not require behavior change on the part of the individual to prevent a disease or disorder from occurring (e.g., eating vitamin-enriched foods, drinking fluoridated water).

What is Passive Primary Prevention?

300

An individual who has been exposed to and harbors a pathogen but has not become ill or shown any of the symptoms.

What is Healthy Carrier?

400

transfer of a disease to a human by a vector.

What is Vector-borne Transmission?
400

A standard set of criteria applied in a specific situation to ensure that cases are consistently diagnosed, regardless of where or when they were identified and who diagnosed the case.

What is Case Definition?

400

An epidemic that arises from a specific source.

What is Common-Source Epidemic?

400

Activities aimed at health screening and early detection to improve the likelihood of cure and reduce the chance of disability or death.

What is Secondary Prevention?

400

An individual who has been exposed to and harbors a pathogen; who is in the beginning stages of the disease; who is showing symptoms; and who has the ability to transmit the disease.

What is Incubatory Carrier?

500

Vector-borne disease transmission processes that occur when the pathogen, so as to spread, uses a host (e.g., a fly, flea, louse, rat) as a mechanism for a ride, for nourishment, or as part of t=a physical transfer process.

What is Mechanical Transmission?

500

An individual (or a group of individuals) who has all the signs and symptoms of a disease or condition but has not been diagnosed as having the disease or had the cause of the symptoms connected to a suspected pathogen.

What is Suspect Case?

500

An epidemic that arises from an infection transmitted from one infected person to another.

What is Propagated Epidemic?

500

Efforts to limit disability by providing rehabilitation where disease, injury, or a disorder has already occurred and caused damage.

What is Tertiary Prevention?

500

Individual who has been exposed to and harbors a pathogen and who can spread the disease at different places or intervals.

What is Intermittent Carrier?