Lesson 10.1: Definition of Terms

Direct Contact Transmission

Spread of infectious organisms from the skin of one person directly

to another person

Indirect Contact Transmission

Spread of infectious organisms by coming into contact with a

contaminated object and then bringing the germ into your body

Airborne Transmission

Blood-borne Transmission

Spread of infectious organisms through direct blood-to-blood contact

Droplet Transmission

Spread of infectious organisms from an infected person in tiny droplets of

fluid that can travel small distances (less than one meter)

Sexual Contact Transmission

Spread of infectious agents from an infected person to another

person through sexual contact

Endemic Disease

Constantly present in a population/region with relatively low spread

Epidemic Disease

Sudden increase in cases spreading through a large population

Pandemic Disease

Sudden increase in cases across several countries/continents/the world

Case

A person who has/suspected of having an infection

Infectivity

The organism's ability to enter & replicate in the host depends on the 3 major factors

Nature of the Agent

Organism's pathogenicity/ Capability to cause disease in a host

Nature of the Host

Host's susceptibility to develop the disease caused by the agent

Environment

Factors that inhibit/promote disease transmission

Incubation Period

The period from the time of exposure up to the appearance of the 1st clinical signs & symptoms

Vector

Any agent that carries & transmits an infectious pathogen into another living organism

Environment

Climate, Housing, Healthcare Settings, Travel (Epidemiologic Triad)

Agent

Virus, Bacteria, Fungi, Parasites (Epidemiologic Triad)

Host

Human & Animal (Epidemiologic Triad)

Chain of Infection

Used to visualize the step-by-step process by which communicable diseases spread from an infected person to an uninfected person

Infectious Agent, Reservoir, Portal of Exit, Mode of Transmission, Portal of Entry, Susceptible Host

6 Chain of Transmission Components