Case Concepts
Disease Transmission
Carrier
Modes of Disease Transmission
Prevention
100

A person in a population who has been identified as having a specific disease. 

What is a case?

100

The habitat where an infectious agent lives, grows, and multiples, and on which it depends for its survival in nature.

What is a reservoir?

100

An individual who has been exposed to and harbors a disease causing organism and who has done so for some time, even though the person may have recovered from the disease.

What is an active carrier?

100

The uninterrupted and immediate transfer of an infectious agent from one person to another. 

What is direct transmission?

100

Preventing a disease/disorder before it happens.

What is primary prevention?

200

The first disease case in a population during an epidemic.

What is a primary case?

200

An inanimate object that can harbor an infectious agent and is capable of being a means or transmission. 

What is a formite?

200

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

What is a healthy or passive carrier?

200

Occurs when a agent is transferred, or carried by some intermediate item, organism, mean, or process to a host, resulting in disease.

What is indirect transmission?

200

Aimed as health screening and detection activities used to identify disease.

What is secondary prevention?

300

The first disease case brought to the attention of the epidemiologist, but not always the primary case. 

What is an index case?

300

An invertebrate animals that transmits infection by conveying the infectious agent from one host to another. 

What is a vector?

300

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

What is a convalescent carrier?

300

Occurs when droplets or dust particles carry the pathogen to the host and cause infection.

What is airborne transmission?

300

Requires behavioral change in the indivdual.

What is active primary prevention?

400

An indivdual who becomes infected and ill after the disease is introduced into a population and who is infected as a result of contact with the primary case. 

What is a secondary case?

400

An infectious organism in vertebrate animals that can be transmitted to humans through direct contact, fomite or vector. 

What is a zoonosis?

400

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

What is an incubatory carrier?

400

Occurs when an arthropod conveys the infectious agent 

What is vector-borne transmission?

400

The limitation of any disability by providing rehabilitation when a disease, injury, or disorder has already occurred and caused damage.

What is tertiary prevention?

500

An individual or group who has all the signs and symptoms of a disease but has not been diagnosed or has the cause of the symptoms connected to a suspected pathogen. 

What is a suspect case?

500

An inanimate intermediary that conveys the infectious agent from its reservoir to a susceptible host.

What is a vehicle?

500

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

What is an intermittent carrier?

500

Occurs when the pathogen undergoes changes as part of its life cycle while within the host/vector and before being transmitted to the new host. 

What is biological transmission?

500

Any attempt to restore an afflicted person to a useful, productive, and satisfying lifestyle. 

What is rehabilliation?